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Annual Report2010 - 2011

Raman Research InstituteBangalore

“”

Scientific research is first and

foremost an expression of the

resurgence of the human spirit in its

search for self-expression.

It represents the response of the mind

of man to the marvellous and ever-

changing panorama of Nature.

Sir C V Raman

contents

IntroductionIntroductionIntroductionIntroductionIntroduction From the Director 6

About the InstituteAbout the InstituteAbout the InstituteAbout the InstituteAbout the Institute History 7RRI at a Glance 9

Areas of RAreas of RAreas of RAreas of RAreas of Researchesearchesearchesearchesearch Astronomy and Astrophysics

Overview 13Ongoing Research 19

Light and Matter Physics


Soft Condensed Matter


Theoretical Physics


FFFFFacilitiesacilitiesacilitiesacilitiesacilities 73

Academic ProgramsAcademic ProgramsAcademic ProgramsAcademic ProgramsAcademic Programs 78

PPPPPeople at RRIeople at RRIeople at RRIeople at RRIeople at RRI 80

PublicationsPublicationsPublicationsPublicationsPublications 90

Other ActivitiesOther ActivitiesOther ActivitiesOther ActivitiesOther Activities 91

AppendicesAppendicesAppendicesAppendicesAppendices 94

Statement of AccountsStatement of AccountsStatement of AccountsStatement of AccountsStatement of Accounts 149

directorfrom the

includes the guidance of students for the conferment of PhD degrees

as part of the PhD programme of the Institute, as well as the active

Visiting Students Programme under which a number of students from

all over the country visit the Institute for stays ranging from a few

weeks to several months and participate in the many research activities

of the Institute. Communications of the ongoing research and also a

sharing of knowledge of current research – in professional talks given

by members of the Institute in conferences and in external institutions

as well as journal review talks at the institute – is another aspect of

our knowledge diffusion. A cultural function of a premier research

institute is the upholding and promotion of academic traditions and

this includes the conduct of specialized seminars on technical topics

targeted at specialized audiences as well as colloquia in a wider

range of topics that are delivered in a style that strives to make current

advances intelligible to a wider community. Additionally, outreach

activities include writings intended for a lay and discerning audience

as well as the delivery of motivational talks at educational institutions.

Included in this report are lists of publications in refereed journals,

conference proceedings as well as in monographs, books and in

popular periodicals, PhD degrees awarded during the period 01

April 2010 to 31 March 2011 as well as seminars and review meetings

focused on current research, which were held at the Institute. The

report also lists the scientists who have visited the Institute from

within India and from overseas during the period.

Bangalore Ravi Subrahmanyan

August 31, 2011 Director

T he annual report of the Raman Research Institute for the year 2010-11 is a summary of the

research and academic activities of the Institute during the year.

The annual report presents synopses of the ongoing knowledge creation activities in the different

research groups, many of which have outcomes in the form of publications in refereed scientific

journals. The Institute considers the transmission of knowledge an important activity; this also

B

history

efore jumping to the next pages in search of thecurrent exciting research activities conducted at theInstitute, take a few moments to read about its history. Inbetween the collection of historical facts you’ll discovera story about the power of basic human curiosity – theinvisible foundation on which the Raman Research Institutewas built and managed by its founder Sir C V Raman andsubsequently by his successors.

In 1934, while still the director of the Indian Institute ofScience (IISc), Raman started the Indian Academy ofSciences and attracted most of the best young scientistsof that time, who published their work in world renownedjournals of physics and chemistry. The same year theMaharajah of Mysore gifted to the Academy 11 acres ofland in the north side of Bangalore. A few years later, Ramanproposed that an independent research institute be builton that premises and an agreement with the Academywas signed.

Raman embarked on a number of long journeys throughoutthe country to raise funds for the new institute. In 1943,the collected sum, along with his personal savings, wasallotted for the construction of the first building. Its initialcompletion coincided with the retirement of Sir C V Ramanfrom IISc in 1948 and in the beginning of 1949 he shiftedall his activities there. The new centre was named after itsfounder – Raman Research Institute.

From the very first moment of its foundation Raman

a brief

8

undertook the management of his new institute withimmense vigour and enthusiasm. He not onlydesigned the main building with the help of anarchitect, but also took great interest in thearrangement of the whole premises. He planted trees,decorative bushes and flowers turning the barrenland around into a beautiful garden. A walk in thatgarden was an indispensable part of his daily life.The initial staff in the new institute consisted of fourpeople including Raman himself. The lack of electricityduring the first two yearsdidn’t affect Raman’s thirstfor knowledge andunderstanding thewonders of Nature. Greatscientific work was carriedout during these yearsusing a few lenses and amanually operatedheliostat. In order tosuppor t his staff andexpand the scientif icactivities at RRI, Raman whowas unwill ing to takemoney from theGovernment, started a couple of chemical industriesalong with one of his former students. He used theprofit to pay his staff and equip his laboratories. Inthe years to come, the institute kept expanding –soon there was a new library, few other buildingsand a museum holding Raman’s personal collectionof gems, crystals and minerals. Until his death inNovember 1970, Raman kept working tirelessly forthe development and growth of the Raman ResearchInstitute.

After his death, the Academy created a publiccharitable trust: the Raman Research Institute Trust.The lands, buildings, deposits, securities, bankdeposits, moneys, laboratories, instruments, and allother movable and immovable properties held bythe Academy for the Raman Research Institute weretransferred to the RRI Trust. The foremost function of

the RRI Trust was to maintain, conduct and sustainthe Raman Research Institute. In 1972, the institutestarted receiving funds from the Department ofScience and Technology of the Government of Indiawhich, since then, has been its main funding source.The same year, Venkatraman Radhakrishnan wasinvited to be the director of RRI. A renowned scientisthimself, Radhakrishnan not only fulfilled C V Raman’sdesire to build an observatory at RRI but formed astrong group in Astronomy and Astrophysics whose

research work today is regarded highly worldwide.Until the mid 90s, the two main areas of researchwere Liquid Crystals and Astronomy andAstrophysics. The constant growth of the Instituteand the expansion of the research interests of itsmembers led to the establishment of two newgroups – Theoretical Physics and Light and MatterPhysics. The Liquid Crystal group was renamed toSoft Condensed Matter which conveys moreaccurately the diverse research activities of itsmembers.

Today, RRI research faculty, scientific staff and studentsconduct active research in the above mentioned fourscientific fields inspired by the example of thefounder – Sir C V Raman.

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GlanceRRI At a

MissionRRI is engaged in fundamental research in the areas ofAstronomy, Astrophysics, Light and Matter physics,Soft Condensed Matter and Theoretical Physics as apart of the global endeavor of humanity to increaseour knowledge and understanding of the world.

DirectorThe current director ofthe Raman ResearchInstitute is RaviSubrahmanyan.

OrganizationRRI is an autonomousresearch institute. Thesupreme body of RRI isthe RRI Trust. Thedirector is the chiefexecutive and

academic officer. The Governing Council is theexecutive body responsible for the administration andmanagement of the Raman Research Institute. TheFinance Committee helps the Council with financialmatters.

LocationRRI is located on a 20 acre plot in the north side ofBangalore City, the IT capital of India. It offers a quietrecluse from the bustling megapolis and a naturalenvironment which is highly conducive to creativescientific work.

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Research AreasAstronomy and Astrophysics



Theoretical Physics

Facilities1. LABORATORIES

A&AA&AA&AA&AA&ARadio Astronomy Labs:

a. Digital Signal Processing (DSP) Labb. RF and MM Wave Labc. X-ray Astronomy Lab

LLLLLAMPAMPAMPAMPAMPQuantum Optics LabLaser Cooling and Light Propagation LabQuantum Interactions LabNon Linear Optics LabLaser-induced Plasma Lab

SCMSCMSCMSCMSCMChemistry LabPhysical Measurements LabLiquid Crystal Display LabRheology and Light Scattering LabX-Ray Diffraction LabBiophysics LabElectrochemistry and Surface Science Lab

MECHANICMECHANICMECHANICMECHANICMECHANICAL ENGINEERINGAL ENGINEERINGAL ENGINEERINGAL ENGINEERINGAL ENGINEERINGMechanical WorkshopGlass Blowing Facility

2. LIBRARY

3. COMPUTER FACILITIES

4. CAMPUS

EducationRRI offers the following academic programs:

– PhD Program– Post Doctoral Fellowship Programs– Visiting Student Program

FundingRRI is funded by the Department of Science andTechnology, Government of India.

Research, Scientific/Technical,Administrative Staff and PhDStudentsResearch Faculty 43

Scientific/Technical 52

Administrative 27

PhD Students 53

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organisation chart

A&A

TP

SCM

LAMP

Administration

Library

Head, Research Facilities

Accounts

Purchase

Stores

Security

Horticulture

Canteen & Catering

Public Relations

Buildings

Maintenance

Electrical

Waste Management

Subramanya

Ramamurthy

B Murthy

Ganapathy

Sasidharan

Narayanappa

Ram

Suresh

R Sasidharan

AS Rao

R Sasidharan

Udaya Shankar

Sanjib Sabhapandit

Sandeep Kumar

Sadiq Rangwala

KrishnamarajuRaghunatha

B Meera

Hema Ramachandran

Computer

Workshops

RAL/Electronics Lab

Nanda Kumar

Ateequlla

RAL CoordinationComm Chairperson - Srivani

GBD Field StationAswathappa

RRI Council Director

RRI Trust

Governmentof India

JourJourJourJourJournal Clubnal Clubnal Clubnal Clubnal Club Supurna Sinha

ColloquiaColloquiaColloquiaColloquiaColloquia Joseph Samuel, Pramod Pullarkat, Sadiq Rangwala

Hostel WHostel WHostel WHostel WHostel Wardenardenardenardenarden Biman Nath

Admissions CoordinatorAdmissions CoordinatorAdmissions CoordinatorAdmissions CoordinatorAdmissions Coordinator Arun Roy

SASASASASAAAAAACCCCC Madan Rao

In-House MeetingIn-House MeetingIn-House MeetingIn-House MeetingIn-House Meeting PhD students

JAP RJAP RJAP RJAP RJAP Rep of RRIep of RRIep of RRIep of RRIep of RRI Shiv Sethi

Complaints CommitteeComplaints CommitteeComplaints CommitteeComplaints CommitteeComplaints Committee KS Srivani (Chairperson), Marisa D’silva, Vrinda J Benegal, K Raghunatha, Madan Rao

Chairpersons ofChairpersons ofChairpersons ofChairpersons ofChairpersons of Reji Philip, Abhishek DharPhD InterPhD InterPhD InterPhD InterPhD Interview Committeesview Committeesview Committeesview Committeesview Committees

Overseas TOverseas TOverseas TOverseas TOverseas Travel Committeeravel Committeeravel Committeeravel Committeeravel Committee Sandeep Kumar (Chairman), Udaya Shankar, Madan Rao

Evaluation CommitteeEvaluation CommitteeEvaluation CommitteeEvaluation CommitteeEvaluation Committee Joseph Samuel, Hema Ramachandran, Biman Nath, Abhishek Dhar, VA Raghunathan

Senior Management TSenior Management TSenior Management TSenior Management TSenior Management Teameameameameam Ravi Subrahmanyan, TN Ruckmongathan, Udaya Shankar, Joseph Samuel, K Krishnamaraju,K Raghunatha

Coordinator ofCoordinator ofCoordinator ofCoordinator ofCoordinator of Supurna SinhaVisiting Students ProgrammeVisiting Students ProgrammeVisiting Students ProgrammeVisiting Students ProgrammeVisiting Students Programme

Coordinator ofCoordinator ofCoordinator ofCoordinator ofCoordinator of Abhishek DharSummer Students ProgrammeSummer Students ProgrammeSummer Students ProgrammeSummer Students ProgrammeSummer Students Programme

ASTRONOANDASTROPH

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overview

OMY

HYSICS

The Astronomy and Astrophysics (A&A) group at RRI comprises 30motivated researchers who study the universe from its creation to itspresent state. The main areas of research include theoreticalastrophysics, observational astronomy, astronomical instrumentationand signal processing.

Theoretical astrophysics concentrates on the development ofanalytical models and computational numerical simulations that try todescribe the dynamics, physical properties and underlyingphenomena of celestial objects (such as stars, planets, galaxies andinterstellar medium, among others) as well as answer fundamentalquestions about the formation and evolution of the universe.

Observational astronomers use numerous telescopes built across theglobe to study the radiation from space covering the entireelectromagnetic spectrum – which ranges from low frequency (longwavelength) radio waves to very high frequency (short wavelengthand extremely energetic) gamma rays. These observations form partof the information that is used to test existing theoretical models andoffer new directions of study. Such studies have been the basis ofour collective knowledge of the universe.

Telescopes have been used since the 17th century to study theuniverse. Today’s highly sophisticated telescopes allow scientists tostudy celestial bodies in different frequency bands of theelectromagnetic spectrum, and answer questions about the universeand its creation. RRI’s astronomical instrumentation engineers areinvolved in the construction and operation of such telescopes aroundthe world.

The following pages summarize the major areas of research for theA&A group as well as each member’s individual work during the lastyear. This section will give the reader a more detailed and technicaldescription of the members’ respective research activities.

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ASTROPHYSICSDevelopment of Cosmological Models: Development of Cosmological Models: Development of Cosmological Models: Development of Cosmological Models: Development of Cosmological Models: Cosmologyis concerned with developing and testing physicalmodels that try to explain the formation andevolution of the universe. Researchers at RRI areworking on developing such models that describeradiation from the Epoch of Reionization (EOR). EORrefers to the period in the early history of the universeduring which the emergence of the first luminoussources (such as stars and galaxies) ionized thepredominantly neutral intergalactic medium. Thesemodels can provide important information aboutthe process of structure formation in the universeand answer questions as to whether such radiationcan be detected with existing telescopes.

Magnetohydrodynamic (MHD) TMagnetohydrodynamic (MHD) TMagnetohydrodynamic (MHD) TMagnetohydrodynamic (MHD) TMagnetohydrodynamic (MHD) Turbulence:urbulence:urbulence:urbulence:urbulence:Turbulence in electrically conducting fluids is a rarelyobserved phenomenon here on Earth. However, ingalaxies, clusters of galaxies and the interstellarmedium, where matter is ionized, it is a widespreadphenomenon. Researchers at RRI are actively workingtowards the development of a comprehensivetheoretical formulation of MHD turbulence.

Dynamo TheorDynamo TheorDynamo TheorDynamo TheorDynamo Theory: y: y: y: y: The astrophysics community at RRIconducts theoretical work to understand the originsof large magnetic fields around cosmic objects (stars,planets and galaxies) and the processes that sustainthem. It is such magnetic fields that protect the Earthfrom the solar wind of particles that would otherwisedestroy life on our planet.

Gravitational Dynamics: Gravitational Dynamics: Gravitational Dynamics: Gravitational Dynamics: Gravitational Dynamics: RRI researchers are alsoinvolved in the construction of models that describethe structure of the orbits of cosmic bodies aroundblack holes. One of the ways of understandinggravitational lensing (the gravitational bending of light),which was predicted by Einstein, is by observingand studying the orbits of stars close to massive blackholes.

OBSERVATIONAL ASTRONOMYHalo and RHalo and RHalo and RHalo and RHalo and Relic Radio Sources: elic Radio Sources: elic Radio Sources: elic Radio Sources: elic Radio Sources: Clusters of galaxiesare the largest structures of matter in the universe.An understanding of their formation, structure anddynamics can bring important insights about theirevolution. Halos and relics are structures within agalaxy cluster that emit strong radiation in the radioportion of the electromagnetic spectrum. Variousmodels exist that attempt to explain the origin ofthis radiation. Currently, researchers at RRI compareobservational data from the radiations of radiogalaxies with AGN have shown that some are slowlydying out. How many such galaxies stay invisible tous because of the limitations posed by the sensitivityof today’s telescope receivers and what bringsabout the end of AGN are some of the questionsthat concern researchers at RRI.

HI RHI RHI RHI RHI Regions in the Milkegions in the Milkegions in the Milkegions in the Milkegions in the Milky Wy Wy Wy Wy Way Interstellar Medium:ay Interstellar Medium:ay Interstellar Medium:ay Interstellar Medium:ay Interstellar Medium: Afterthe Big Bang, some 13.7 billion years ago, hydrogenwas created in great quantities in the universe makingit the basic building block of stars. The spacebetween stars is filled with neutral hydrogen atextremely low densities compared to the air webreathe on Earth. The emissions from these hydrogenregions – called HI regions – carry information aboutthe conditions before star formation. Researchers atRRI look at the formation and structure of such HIregions using observational data from various radiotelescopes in India and abroad.

Pulsars: Pulsars: Pulsars: Pulsars: Pulsars: The detection of pulsars was a serendipitousdiscovery. Pulsars are neutron stars that originate insupernovae and spin very fast due to theconservation of angular momentum and periodicallyemit radio waves. Because of their periodic emission,pulsars are often called “the lighthouses of theuniverse”. We can only observe pulsars that beam inthe direction of Earth. Pulsar emissions provide insightabout their structure and distance. They are also awonderful experimental platform to test generalrelativity. Today, millisecond pulsars are one of the

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most accurate clocks that have been found in theuniverse. RRI continues to conduct active researchon pulsars and develop receivers that could revealfurther details about their nature.

Lifecycle of Radio Galaxies: Lifecycle of Radio Galaxies: Lifecycle of Radio Galaxies: Lifecycle of Radio Galaxies: Lifecycle of Radio Galaxies: As radio telescopesbecome increasingly sensitive and of greaterresolution, intricate features and morphologies of andwithin radio galaxies can be observed. A particulartype of galaxy, called restarting radio galaxies, hascaptured the interest of researchers at RRI. It isbelieved that activity in the nucleus of the galaxyhad stopped and then started again fresh. Such ascenario would explain the observations made andprovide a useful input to our understanding of the

evolution and lifecycle of radio galaxies. Why didthe nucleus die, how long was it dead before itrestarted its activity, what are the mechanisms thattriggered its rebirth – those are some of the questionsRRI astronomers are trying to answer in collaborationwith Indian and international colleagues.

Radio Galaxy Morphologies: Radio Galaxy Morphologies: Radio Galaxy Morphologies: Radio Galaxy Morphologies: Radio Galaxy Morphologies: In recent years, X-shaped radio galaxies have caught the interest ofthe astronomy community, and members of the A&Agroup at RRI are active participants in this researchfield. In X-shaped radio galaxies, the typical two

lobes are accompanied by two others to form aradio galaxy whose lobes look like the letter X. Twoof the lobes are active while the other two are dead.Theories compete to explain how the two additionallobes are generated. Current observations at RRI areused to test these theories and deepen ourunderstanding of X-shaped radio galaxies.

INSTRUMENTATION – DESIGN ANDDEVELOPMENTRRI is involved in the design and development ofseveral telescopes across the world.

Most current antenna systems are based on largereflectors with a single or a small number of feeds.The Murchison Widefield Array (MWA) and LOFARprototypes have heralded a paradigm shift in thedesign of next generation of radio telescopes.Science projects like EOR and transients have pushedthe interesting range of frequencies for many nextgeneration radio telescopes to less than a GHz withsignif icantly improved sensit ivity with largebandwidths and large field of view. This can berealized with a phased array or Aperture Array (AA),where the number of beams depends only on theavailable processing power and availablecommunications.

RRI has accumulated expertise in this field with itsinvolvement in Guaribidanur Radio telescope,Mauritius Radio Telescope, MWA and developmentof broadband feed for Greenbank Radio Telescope.

With this background, the institute has embarked ona programme to develop the Aper ture Arraytechnology in the frequency range 50 to 1000 MHzand has initiated design process for an RRI ApertureArray telescope prototype. With this motivation, RRIhas initiated development of

1. A broadband antenna capable of operating overthe frequency range 50 to 1000 MHz.

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2. A low noise signal conditioner chain withsufficient amplification to digitize signals from abroadband antenna.

3. A high speed digitizer (10 data bits with a 2GHz sampling rate) and a data aggregationboard.

To facilitate design, RRI carried out on a small scaleinterference monitoring campaign in GBD andBangalore, and initiated discussion with TexasInstruments to design a single chip signal conditionerfollowed by a high speed analogue to digitalconverter. The present status has been summarisedin two short technical reports. The design anddevelopment of high speed A to D converter anddata aggregation cards are under progress.

Mauritius Radio TMauritius Radio TMauritius Radio TMauritius Radio TMauritius Radio Telescope (MRT): elescope (MRT): elescope (MRT): elescope (MRT): elescope (MRT): MRT was built inthe late 1990s in Bras d’Eau at the north-east side ofMauritius, as a joint effort by RRI, Indian Institute ofAstrophysics and University of Mauritius. It is a T-shaped 2x1 km aperture synthesis ar ray thatobserved the sky at 151.6 MHz in the declinationrange of -70° to -10°. The scientific objectives ofMRT are to produce radio surveys of the southernsky, observe and study pulsars, solar radio emission,extragalactic radio sources, supernova remnants andsteep spectrum sources. In the new phase of MRTdata analysis, the group had re-established the arraygeometry (an error of 1mm/m was established)which weeded out systematics in the position ofsources in the MRT images, generated new calibrationtables and new PSFs for deconvolution and alsodeveloped field-of-view calibration. With these newdevelopments the group has been able to completeimaging of an additional steradian of the sky coveringthe declination range -70° to -10° and the siderealhour range 00hr to 06hr. Imaging the sidereal hourrange 07 hr to 18 hr is under progress.

The data analysis for the RA range 07 to 18 hr hasmet with certain difficulties. The problems faced aretwofold: At the first level the quality of data for theseRA ranges are very poor. This leads to incomplete

(uv) coverage and leads to very poor dynamic rangeimages, especially in regions close to the galacticplane. In addition, a good consistent flux densitycalibration for the four delay zones has not beenpossible. Work is in progress to overcome theseproblems.

In the mean time, the Institute has started cataloguingextended sources seen in MRT survey. Crossidentification of around 300 sources listed asextended in the 843 MHz images made using theMolongo Observatory Synthesis Telescope (MOST),reported by Jones and McAdam has been carriedout. More than 100 common sources have beenidentified. Similarly along the galactic plane around

thirty and odd extended SNRs have been identifiedusing Green’s catalogue. A thorough investigation offlux-calibration and positions of these features isunderway.

Giant MeterGiant MeterGiant MeterGiant MeterGiant Meterwave Radio Twave Radio Twave Radio Twave Radio Twave Radio Telescope (GMRT): elescope (GMRT): elescope (GMRT): elescope (GMRT): elescope (GMRT): GMRT isthe largest low frequency telescope in the world.The collaboration between Tata Institute ofFundamental Research (TIFR), Mumbai, which currentlyoperates the telescope, and RRI has been a longtradition. RRI has previously developed receivers inthe 20-cm band as well as specialized receivers forpulsar observations that have been installed in GMRT

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to improve its observational capabilities. Currently,researchers and students at RRI are developing 50MHz high sensitive receivers for the telescope. Suchreceivers have been installed on four of GMRT’santennas. After extensive testing, a proposal has beensubmitted for the fabrication and installation of thesereceivers on all 30 antennas to carry out an all-skysurvey at 50 MHz with unprecedented sensitivity andresolution in the low frequency regime. Lowfrequency surveys allow for statistical analysis ofastronomical objects with high redshifts and alsoprovide foreground information crucial for studiesof the EOR.

WWWWWideband Rideband Rideband Rideband Rideband Receivers on the Green Bank Teceivers on the Green Bank Teceivers on the Green Bank Teceivers on the Green Bank Teceivers on the Green Bank Telescope:elescope:elescope:elescope:elescope:Researchers at RRI have developed a wideband multi-channel receiver for pulsar observations that wasrecently installed in the largest single dish telescopein the world – the Green Bank Telescope in WestVirginia, USA. The receivers allow for high-time andspectral resolution of pulsar emissions. Data from theobservations is currently being analyzed.

Decameter WDecameter WDecameter WDecameter WDecameter Wave Radio Tave Radio Tave Radio Tave Radio Tave Radio Telescope at Gauribidanur:elescope at Gauribidanur:elescope at Gauribidanur:elescope at Gauribidanur:elescope at Gauribidanur:The decameter wave radio telescope at Gauribidanur(80 km north of Bangalore) was built and is operatedby RRI and Indian Institute of Astrophysics. This is a1.4 km (E-W wing) by 0.5 km (South wing) T-shapedarray consisting of 1,000 dipole antennas. Radioemissions from the sun’s corona and various radiosources at 34.5MHz have been observed using thetelescope. RRI researchers are currently analyzingpulsar data collected using the E-W wing of thetelescope.

Murchison WMurchison WMurchison WMurchison WMurchison Widefield Aridefield Aridefield Aridefield Aridefield Array (MWray (MWray (MWray (MWray (MWA): A): A): A): A): MWA project isan international effort to design and build a novellow-frequency radio telescope to observe signalsfrom the Epoch of Reionization, measure theheliospheric plasma and conduct a high sensitivitysurvey of the dynamic radio sky. The MWA will consistof 8,000 dual-polarization dipole antennas

optimized for the 80-300 MHz frequency range,arranged as 512 “tiles”, each a 4x4 array of dipoles.A test bed of 32 tiles have already been deployedin the radio-quite zone near the town of Geraldtonin Western Australia, providing the first sets of datafrom the instrument. RRI is a full partner in this projectalong with US and Australian institutions. Engineersand scientists from the A&A group have designed,built and tested the digital receivers and dataprocessing electronics for the MWA telescope.Currently, they are looking at data collected with the32-tile test bed in an attempt to understand theefficacy of different observing, calibrating, and data

processing strategies for the detection of signals fromthe EOR.

3m submm wave telescope prototype (3mST3m submm wave telescope prototype (3mST3m submm wave telescope prototype (3mST3m submm wave telescope prototype (3mST3m submm wave telescope prototype (3mSTeP):eP):eP):eP):eP):Members of the A&A group are currently involvedin the hardware development of a 3m submm wavetelescope which would serve as a prototype forthe development of a 30m telescope. Theconstruction of a telescope at this frequency wouldallow researchers to study interstellar clouds anddust, where stars and galaxies are formed and wheremm and submm waves travel unabsorbed.Observations would also bring valuable information

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about the cosmic microwave background (CMB),the afterglow of the enigmatic gamma ray burst, starformation processes at high redshift and many more.

However, the major problem at these frequencies isthe Earth’s atmosphere which is opaque for most ofthe band. That requires telescopes to be deployedat high altitudes in order to minimize the travel ofsubmm waves through the atmosphere. Membersof the A&A group are currently involved in thehardware development of a 3m submm wavetelescope which would serve as a prototype forthe development of a 30m telescope. They havealready resolved challenges in the mechanical designof the dish and the development of an energyefficient motor system needed for the remotedeployment where power grid doesn’t reach. Thegroup is currently working on the construction ofvery broadband 8GHz spectrometers needed forthe telescope receiver system.

XXXXX-ray P-ray P-ray P-ray P-ray Polarimeter: olarimeter: olarimeter: olarimeter: olarimeter: The A&A group has expanded itsobservations beyond radio and mm waves to theX-ray region of the spectrum. RRI has built a fullyequipped lab for fabrication and testing of X-raydetectors and currently, researchers are working onthe development of an X-ray polarimeter sensitive inthe energy range of 5-30 keV. The instrument will belaunched in to space in collaboration with ISRO. ThePI of the project says: “The X-ray astronomicalresearch and in a broader context, high-energyastrophysics research will be strongly enriched fromX-ray polarisation measurements of many kinds ofastrophysical objects. In absence of any X-raypolarisation mission presently approved anywherein the world, the proposed experiment will be thepathfinder of future, more sensitive experiments arerequired.” Earth’s atmosphere completely absorbsphotons in the X-ray and gamma-ray band. Therefore,observations of X-ray sources can be carried outonly from space platforms like balloons, rockets, orsatellites. To achieve a reasonable sensitivity, the

proposed experiment requires very longobservations of bright X-ray sources that are onlypossible from a satellite.

ASTROSAT is the name given to Indian SpaceResearch Organization’s (ISRO) satellite mission formulti-wavelength astronomy scheduled to belaunched in a 650 km near equatorial orbit in 2011.Its major scientific goals include:

(i) simultaneous multi-wavelength monitoring ofintensity variations in a broad range of cosmicsources;

(ii) broadband spectroscopic studies of X-raybinaries, AGN, clusters of galaxies and stellarcoronae;

(iii) sky surveys in the hard X-ray and UV bands;

(iv) studies of periodic and non-periodic variabilityof X-ray sources and more. ASTROSAT willcarry five astronomy payloads for simultaneousmulti-band observations. RRI is currentlyinvolved in the development of Large Area X-ray Proportional Counter (LAXPC) for X-raytiming and low-resolution spectral studies overa broad energy band. One of the payloadson ASTROSAT will consist of three LAXPCs.

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ongoingresearch

The areas of scientific exploration for N Udaya Shankar include skysurveys, detection of EOR, aperture arrays and instrumentationand signal processing for radio astronomy.

Udaya Shankar Udaya Shankar Udaya Shankar Udaya Shankar Udaya Shankar manages the Murchison Wide Field Array (MWA)project, both in his capacity as Member of the MW Board and asDeputy Project Manager (India). One of the main science goals ofthis array is to detect signal from the EOR. In collaboration withHarish Vedantham and Ravi Subrahmanyan, he studied imagingmodes and strategy for MWA to detect EOR. As a first step,appreciating that limiting the confusion from galactic andextragalactic foregrounds is critical to the success of MWA, thefrequency structure of the three dimensional point spread function(PSF) of MWA is being studied. The 3D PSF has the peculiar propertythat structures in the two angular dimensions get coupled tofrequency axis, which maps the Line of Sight (LOS) distance. Aformalism to estimate the foreground contamination alongfrequency, or equivalently LOS dimension, and establish arelationship between foreground contamination in the image planeand visibility weights on the Fourier plane is being estimated. Twodominant sources of LOS foreground contamination have been

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identified by Udaya Shankar and his collaborators –“PSF contamination” and “gridding contamination”.Their research showed that a judicious choice ofthe frequency window function can minimizecoupling of angular structures in PSF to the frequencyaxis. They are also looking at the role of imagingalgorithms in minimizing the stochastic noise in the3D PSF due to gridding.

Udaya Shankar is also working on the developmentof aperture array technology and prototyping foran RRI Aperture Array telescope in collaboration withAA Deshpande, Ravi Subrahmanyan, Srivani,Somashekar, and members of RAL. Udaya Shankarand his collaborators from RRI and RAL are alsodeveloping Aperture Array technology in thefrequency range 50 to 1000 MHz and have initiateddesign process for an RRI Aperture Array telescopeprototype.

Work continued on the previous year’s all-sky surveyat 150 MHz using the Mauritius Radio Telescope(MRT). In the new phase of MRT data analysis, UdayaShankar and his collaborators re-established the arraygeometry (an error of 1mm/m was established)which weeded out systematics in the position ofsources in the MRT images, generated new calibrationtables and new PSFs for deconvolution and alsodeveloped field-of-view calibration. These newdevelopments have enabled the complete imagingof an additional steradian of the sky.

The cataloguing of extended sources seen in theMRT survey has also begun. Cross identification ofaround 300 sources listed as extended in the 843MHz images made using the Molongo ObservatorySynthesis Telescope (MOST), reported by Jones andMcAdam has been carried out. More than 100common sources have been identified. Similarlyalong the galactic plane, around 30 extended SNRshave been identified using Green’s catalogue. Athorough investigation of flux-calibration andpositions of these features is underway.

KS DwarakanathKS DwarakanathKS DwarakanathKS DwarakanathKS Dwarakanath’s research interests lie in the fieldsof extragalactic astronomy, clusters of galaxies, haloand relic radio sources, the galaxy and interstellarmedium. His work during the year has been largelyfocused on halo and relic radio sources.

Radio halos and relics are believed to be associatedwith cluster mergers, although not all merging clustershost them. The X-ray surface brightness distributionsof merging clusters typically exhibit non-concentriciso-intensity contours, small-scale structures, multiplepeaks and/or poor optical and X-ray alignments. Theaim of the MAssive Cluster Survey (MACS) is tocompile a statistically complete sample of very X-ray luminous (and therefore massive) distant clustersof galaxies in the redshift range of 0.3 to 0.6. Alongwith Siddharth Malu and Ruta Kale, Dwarakanath hasimaged six of the hottest and most luminous clustersselected from the MACS at 230 MHz and 610 MHzusing the GMRT. All the clusters chosen had disturbedX-ray morphologies, implying that they may haveundergone mergers. Of the six cluster fields, fourexhibited diffuse and filamentary radio emissions likelyto be of cluster origin. The most spectacular radiohalo was discovered in the second brightest clusterin the sample: this radio halo extended along theNorth-West, similar to the morphology of the X-rayemission confining the halo emission. The 1400 MHzradio luminosity of the halo is in agreement with thevalue expected from the Lx-Lr correlation for clusterhalos. Dwarakanath and his colleagues are studyingthe implications of these detections.

Dwarakanath and Ruta KaleRuta KaleRuta KaleRuta KaleRuta Kale, in collaboration withJoydeep Bagchi and Surajit Paul of the Inter-UniversityCentre for Astronomy and Astrophysics (IUCAA),Pune, have also been studying ring-like double radiorelics in the merging, rich galaxy cluster A3376 tobetter understand non-thermal phenomena at clusteroutskirts. This study has produced the first lowfrequency (330 and 150 MHz) images of the doublerelics using the GMRT. With the help of the GMRT

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330 MHz map and the existing VLA 1400 MHz map,the distribution of spectral indices over the radiorelics have been constructed and analyzed. Theresearchers found flat spectral indices at the outeredges of both the relics and a gradual steepeningof spectral indices toward the inner regions, therebysupporting the model of outgoing merger shockwaves. The eastern relic showed a complexmorphology and complex spectral index distributiontoward the inner region. This is an area of study thatis being looked into in the context of the effect oflarge scale accretion flows on the outgoing mergershocks as per recent simulations.

Radio relics in galaxy clusters can be produced byelectrons accelerated at cluster merger shocks orby adiabatically compressed fossil radio cocoonsor by dying radio galaxies. The spectral evolution ofradio relics is affected by the pressure of thesurrounding thermal plasma. Dwarakanath and RutaKale also presented a low frequency study of threeradio relics present in the environments of densecluster core (A4038), in the cluster outskirts (A1664)and in the filaments (A786). Multi-frequency – threeor more frequencies in the range 150-1400 MHz –imaging of these relics indicates the following:

• The spectral indices of the relics progressivelysteepen as the environment becomes denser,i.e., relics in rarer environments have flatterspectra compared to relics at the cluster centre.Similarly the sizes of the relics range from _ 200kpc to _ 1.6 Mpc as one goes from denser torarer environments. This is consistent with theexpectation of steepening of the spectral indexdue to the confinement of the relativistic plasmaby the intra-cluster medium.

• Low frequency images from GMRT of the relic inA4038 led to the discovery of steep spectrumemission much larger in extent than was knownfrom 1400 MHz images.

• Best fits to the integrated spectra of these relicsin the framework of the adiabatic compressionmodel were obtained. The spectrum of A4038relic can be best fit by a model of adiabaticallycompressed plasma. The spectra of relics inA1664 and in A786 are best fit by a model of afossil radio galaxy.

• Spectral index maps of all the three relics donot show any obvious gradients indicating theabsence of shocks in these systems.

Biman NathBiman NathBiman NathBiman NathBiman Nath’s research interests lie in the field ofcosmology, structure formation and extragalacticastronomy. X-ray observations of intracluster medium(ICM) gas have shown that there is a universalpressure profile of the gas. Nath’s research activitiesduring the year included using this gas pressureprofile to determine the entropy injected into theICM, with the aim of shedding light on the possibleevolution of the entropy injection. The gas profilewas compared with the profile expected in theabsence of any entropy injection. With datacollected by S Majumdar of TIFR, it was found thatthere exists a simple scaling of the entropy injectionwith the cluster mass. The results of this studyindicate, for the first time, that the entropy injectiondecreases with increasing redshift. This paper hasbeen accepted in MNRAS.

Nath has continued his research work on galacticoutflows with radiation pressure. It has beenobserved that the maximum speed of cloudsembedded in galactic outflows is 2-3 times therotation speed of disc galaxies. In collaboration withPhD student Mahavir Sharma and Y. Shchekinov ofSouthern Federal University in Russia, Nath explainedthis phenomenon analytically by calculating theterminal speed of winds from disc galaxies that aredriven by radiation pressure on dust grains. Thispaper has been published in ApJ Letters.

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AAAAAvinash A Deshpandevinash A Deshpandevinash A Deshpandevinash A Deshpandevinash A Deshpande’s activities during the yearincluded further analysis of the 12-hour synthesis OH-line data in the direction of W49N from VLBA tobetter understand the significant scattering due tothe intervening interstellar medium. Detailed highangular-resolution images at 1612, 1665 and 1667MHz revealed scattered broadened OH spots (afew tens of milli-arc-seconds in size), indicating notonly anisotropic scattering (axial ratios between 1.5to 3) with the position angles of the spot imagesoriented perpendicular to the galactic plane andangular broadening being much smaller thanreported by earlier studies, but also significantdifferences in scatter broadened images for the twohands of polarization. These differences suggest thatthere might be significantly different scatteringscreens sampled by the two polarizations, as wouldbe expected in principle, in the presence ofmagnetic field along the sightline. This work was incollaboration with W. M. Goss from NRAO, R.Ramachandran from San Jose, Jose E. Mendoza-Torres from Instituto Nacional de Astrofisica, Opticay Electronica (Mexico), and Tanmoy Laskar fromHarvard University.

Also being analyzed are pulsar observations madein 2009 using the multi-band receiver with GBT.Related developments includes implementingsecond phase firmware to enable online spectraland Stokes parameter computation and integration,and exploring/testing alternative solutions for animproved method to record data, aimed to reducepossible slips (missing packets), as well as testing alog-periodic array element for use in the GBT multi-band feed. People involved include C Vinutha,Jayanth Channamagalam of University of West Virginia,Durai Chelvan, and project students S. G. Sahanaand Nandan Roy.

Attempts were made to extract large-scaledistribution of cold HI in the Milky Way incollaboration with Gauri Kulkarni of Pune, John Dickey

of the University of Tasmania and SnezanaStanimirovic of the University of Wisconsin-Madison.

In the estimated structure functions for both HIemission and optical depth, the galactic spiralstructure shows its imprint, and the emission dataserves as a reference set in revealing that signatureexclusively, wherein the correlations between thespiral arm and inter-arm regions, and arm-to-armresult in significant modulation. Similar modulationwas also seen in the structure function for the opacity(optical depth). However, it seems to significantlylevel-off beyond a few 100 pc, if not around 100-pc scale. This is suggestive of an outer-scale forcoherent structure in opacity on the scales of shelland super-shells.

In collaboration with Richard Dodson from ICRAR(Australia) and Dave McConnell of ATNF (Australia)the radio nebula that surrounds the X-ray PWNemission imaged by Chandra Observatory wasstudied some years ago at high frequencies usingthe ATCA. As a follow-up, full-Stokes imaging of theradio nebula using GMRT at 610 and 1420 MHz wasproposed to study its evolution with frequency. Thedata for the first run of these observations (madeby the team including Richard Dodson and WasimRaja) are being analyzed using a DiFX correlator setupwith cluster computing at ICRAR, including off-linebinning of the data on the pulsar phase.

Development of a suitable spectral analysis pipelineto process time-sequences from X-ray binaries, as apreparatory step to study QPOs, is undertaken. Thesoftware, on which initial tests are being conducted,allows flexible extraction, calibration and reductionof data, usually acquired with several detectors. Thisstudy is in collaboration with Harsha Raichur of IUCAAand Nishant Singh.

Ravi SubrahmanyanRavi SubrahmanyanRavi SubrahmanyanRavi SubrahmanyanRavi Subrahmanyan’s research during the year wasfocused on the epoch of reionisation.

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He studied the mechanisms by which foregroundradio sources on the sky contaminate attempts toimage the red-shifted 21-cm signals from the EOR.The contamination was shown to be separable intoa PSF contamination component that originated viathe leakage of sources through side-lobes of thesynthetic point spread function of the interferometertelescope, and a gridding contamination componentthat was caused by the imaging algorithm commonlyused in Fourier synthesis imaging. The study led todevising methods by which confusion-free regimesmay be created via a transformation to a domain

where the contamination may be confined andseparated from the EOR signals. Numerical simulationsof the effects of contamination supported theanalytic work and the efficacy of the proposedmethods was demonstrated. This work was incollaboration with Harish Vedantham and N UdayaShankar.

Subrahmanyan, along with A Raghunathan, NipanjanaPatra and Udaya Shankar, is developing systems forthe measurement of all-sky averaged radio spectrumin the frequency range 87.5-175 MHz so as tomeasure the all-sky signatures from the EOR. Bothinterferometer methods and single element systems

have been deployed at the Gauribidanur field stationand the system performance is being analysed anddeveloped further.

Biswajit PBiswajit PBiswajit PBiswajit PBiswajit Paulaulaulaulaul’s research activities during the yearincluded developmental work for an X-raypolarimeter and ASTROSAT and the investigation ofvarious aspects of compact X-ray sources.

He has been working on developing an X-raypolarimeter for a future small astronomy satellitemission. X-ray polarisation measurement is a still-unexplored area and has strong potential forunderstanding several impor tant high energyastrophysics problems.

X-ray polarisation measurement is a unique tool thatmay provide crucial information regarding theemission mechanism and the geometry of variousastrophysical sources, like neutron stars, accretingblack holes, pulsar wind nebulae, AGNs, andSupernova Remnants, and can help probe matterunder extreme magnetic fields and extremegravitational fields. Although the three other domainsof X-ray Astronomy – timing, spectral and imaging –are well developed, there has been very littleprogress in X-ray Polarimetry with only one definitivepolarisation measurement and a few upper limitsavailable so far. A proposal for a scatteringpolarimeter has been submitted to the Indian SpaceResearch Organization (ISRO) for a dedicated smallsatellite mission and a laboratory unit has been built.

The work carried out at RRI includes the following:

• Fabrication of an engineering model of the X-raypolarimeter; the detector and collimator designhas been completed.

• A mechanical analysis of the engineering modelof the detector system has been carried out.

• Fabrication of two detector units has started.Assembly of one of these detectors is in progress.

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• Position determination of the X-ray events by thecharge division method has been accomplished.This technique has been tested successfully in arectangular detector and a cylindrical detector.

• Design and test of the front end electronics hasbeen completed. Engineering model fabricationof the front end electronics is to start soon.

• Design and development of the processingelectronics and the common electronics units arein a very advanced stage.

PV Rishin, MR Gopalakrishna, R Duraichelvan, CMAteequlla and members of RAL and MES havecontributed to these progresses.

In collaboration with ISAC, Bangalore, and SAC,Ahmedabad, Paul worked on the development ofthe ASTROSAT-LAXPC data reduction software. Heis also LAXPC representative in the ASTROSATGround Segment Committee that will take care of allASTROSAT activit ies other than hardwaredevelopment and Astrosat Calibration Committee.

The year gone by has seen significant contributionsin the areas of orbital evolution studies of X-raybinaries; quasi-periodic oscillations in accretingpulsars and black holes; and complex pulse phaseand orbital phase dependence of broadband X-ray spectrum in accreting pulsars, among others. Asummary of these studies follows.

Radiation from accreting black holes in their thermaldominated (High Soft) state is expected to bepolarised due to scattering in the plane parallelatmosphere of the disk. Also, special and generalrelativistic effects in the innermost parts of the diskpredicts energy dependent rotation in the plane ofpolarisation and some distinct signatures which canbe used as a probe for measuring the parameters ofthe black hole like its spin, emissivity profile and theangle of inclination of the system. An analysis ofexpected minimum detectable polarisation wascarried out from some of the galactic black hole

binaries GRO J1655-40, GX339-4, H1743-322, CygX-1 and XTE J1817-330 in their thermal dominatedstate with a proposed Thomson X-ray Polarimeter.Along with the measurement of the degree ofpolarisation, the polarisation angle measurement isalso important, and hence the error in the polarisationangle measurement for a range of detectionsignificance was also obtained. This analysis wascarried out in collaboration with Chandreyee Maitrafrom RRI.

Paul and Chetana Jain of Delhi University carried outan X-ray eclipse timing analysis of the transient lowmass X-ray binary XTE J1710-281. They reportedobservations of 57 complete X-ray eclipses, madewith the proportional counter array detectorsaboard the RXTE satellite. Using the eclipse timingtechnique, they derived a constant orbital period.Two instances of discontinuity were also discoveredin the mid-eclipse time, one before and one afterthe above MJD range. These results are interpretedas three distinct epochs of orbital period in XTEJ1710-281. The only other X-ray binary withunambiguous detection of orbital period glitch isEXO 0748-676.

4U 1822-37 is a Low Mass X-ray Binary (LMXB) systemwith an Accretion Disk Corona. 16 new mid-eclipsetime measurements of this source have beenobtained during the last 13 years using X-rayobservations made with the RXTE-PCA, RXTE-ASM,Swift-XRT, XMM-Newton and Chandra observatories.These, along with the earlier known mid-eclipsetimes, have been used to accurately determine thetimescale for a change in the orbital period of 4U1822-37. X-ray pulsations from the source were alsodetected. In view of these results, Paul and ChetanaJain have put forth various mechanisms that couldbe responsible for the orbital evolution in this system.Using the long-term RXTE-ASM light curve, it wasfound that the X-ray intensity of the source hasdecreased over the last 13 years by ~40% and there

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are long-term fluctuations at time scales of about ayear. In addition to the long-term intensity variation,significant variation in the intensity during the eclipsehas also been observed.

Jincy Devasia and Marykutty James from MGUniversity in Kottayam and Biswajit Paul carried out adetailed timing and spectral analysis of Rossi X-rayTiming Explorer Proportional Counter Array (RXTE-PCA) data obtained from observations during theoutburst of a transient X-ray pulsar 1A 1118-61 inJanuary 2009. The pulse profile showed significantevolution during the outburst and also significantenergy dependence – a double-peaked profile upto 10 keV and a single peak at higher energy. Quasi-periodic oscillations (QPOs) at 0.07-0.09 Hz werealso detected. The magnetic field strength calculatedusing the QPO frequency and the X-ray luminositywas found to be in agreement with the magneticfield strength measured from the energy of thecyclotron absorption feature detected in this source.The 3-30 keV energy spectrum over the 2009outburst of 1A 1118-61 was well fitted with a partialcovering power-law model with a high-energy cut-off and an iron fluorescence line emission. The pulsephase resolved spectral analysis showed that thepartial covering and high-energy cut-off modelparameters have significant changes with the pulsephase.

Paul, Devasia and James also made a detailedinvestigation of the timing and spectral propertiesof the transient X-ray pulsar GX 304-1 during itsoutburst in August 2010, using observations carriedout with the RXTE-PCA satellite. They detected strongintensity and energy dependent variations in thepulse profiles during the outburst. The pulse profileshowed significant evolution over the outburst. Itshowed complex structures consisting of a mainpeak with steps on both sides during the start ofthe outburst. On some days, a sharp dip like featurewas seen which disappeared at the end of the

outburst; when the profile evolved into a sinusoidalshape. At low energies, the pulse profiles appearedcomplex, consisting of multiple peaks and a narrowminimum. The amplitude of the second brightestpeak in low energies decreased with energy, andabove 12 keV, the shape of the pulse profilechanged to a single broad peak with a dip likefeature. The dip had energy dependence, both inphase and in width. QPOs were detected at 0.125Hz with a harmonic. The QPO feature had a low rmsvalue of 2.9% and it showed a positive energydependence up to 40 keV with the rms valueincreasing to 9% at 40 keV. The QPO frequencydecreased from 0.128 Hz to 0.108 Hz in 12 days.As before, the 3-30 keV spectrum could be wellfitted with a partial covering power-law model witha high energy cut-off and iron fluorescent lineemission. For a few of the observations carried outduring the decay of the outburst, the partial coveringabsorption component was found to change tosingle component absorption. The partial coveringand high energy cut-off parameters varied significantlywith the pulse phase.

After a long quiescence of three decades, thetransient X-ray pulsar 4U 1901+03 became highlyactive in February 2003. The analysis of RXTE-PCAobservations of this source showed severalinteresting features like X-ray flares, a broadening ofthe pulse-frequency feature, and QPOs. The X-rayflares showed spectral changes, had a duration of100-300 s, and were more frequent and strongerduring the peak of the outburst. During the outburst,Paul, Marykutty James and Jincy Devasia alsodetected a broadening of the pulse-frequency peakas well as intensity-dependent changes in the pulseprofile at very short time-scales. This reveals acoupling between the periodic and the low-frequency aperiodic variabilities. In addition, near theend of the outburst a strong QPO feature centredat ~0.135 Hz was detected. Using the QPO

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frequency and the X-ray luminosity during the QPOdetection period, the magnetic field strength of theneutron star was estimated and found to beconsistent with the value inferred earlier under theassumption of spin equilibrium.

Paul and Sachi Naik of PRL measured the timing andbroad-band spectral properties of the Be transienthigh-mass X-ray binary pulsar GRO J1008-57 using aSuzaku observation in the declining phase of itsNovember and December 2007 outbursts. Pulsationswith a period of 93.737 s were clearly detected inthe light curves of the pulsar up to the 80-100 keVenergy band. The pulse profile was found to bestrongly energy dependent, a double-peaked profileat soft X-ray energy bands (<8 keV) and a single-peaked smooth profile at hard X-rays. The broad-band energy spectrum of the pulsar, reported forthe first instance from this work, is well describedwith three different continuum models, namely (i) ahigh energy cut-off power law, (ii) a Negative andPositive power law with EXponential (NPEX) cut-offand (iii) a partial covering power law with high energycut-off. In spite of large value of absorption columndensity in the direction of the pulsar, a blackbodycomponent of temperature ~0.17 keV for the softexcess was required for the first two continuummodels. A narrow iron Kα emission line wasdetected in the pulsar spectrum. The partial coveringmodel, however, was found to explain the phase-averaged and phase-resolved spectra well. The dip-like feature in the pulse profile was explained by thepresence of an additional absorption componentwith high column density and covering fraction atthe same pulse phase.

A comprehensive spectral analysis of the high massX-ray binary (HMXB) pulsar Centaurus X-3 was carriedout using data obtained with the Suzaku observatorycovering nearly one orbital period. The light curveshowed the presence of extended dips which arerarely seen in HMXBs. During this observation, these

dips were seen up to as high as ~40 keV. The pulsarspectra during the eclipse, out-of-eclipse, and dipswere found to be well described by a partialcovering power-law model with high energy cut-off and three Gaussian functions for 6.4 keV, 6.7 keV,and 6.97 keV iron emission lines. The dips in thelight curve were explained with the presence of anadditional absorptioncomponent with highcolumn density andcovering fraction, thevalues of which werenot significant duringthe rest of the orbitalphases. The iron lineparameters during thedips and eclipse weresignificantly differentcompared to thoseduring the rest of theobservation. Duringthe dips, the iron lineintensities were foundto be lower by a factorof 2-3 with significantincrease in the lineequivalent widths.However, thecontinuum flux at thecorresponding orbitalphase was estimatedto be lower by morethan an order ofmagnitude. Similaritiesin the changes in theiron l ine flux andequivalent widthsduring the dips andeclipse segments suggests the dipping activity in CenX-3 is caused by obscuration of the neutron star bydense matter, probably structures in the outer region

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of the accretion disk, as in case of dipping low massX-ray binaries. This study was done in collaborationwith Sachi Naik from PRL.

Paul and Chetana Jain also studied the pulse profilestability of the Crab pulsar. An X-ray timing analysisof the Crab pulsar, PSR B0531+21, was carried outusing archival RXTE data. The stability of the Crab pulse

profile, in soft (2-20keV) and hard (30-100keV) X-ray energies,over the last decade ofRXTE operation wasinvestigated. Theanalysis includedmeasurement of theseparation betweenthe two pulse peaksand intensity and thewidths of the twopeaks. No significanttime dependency inthe pulse shape wasfound. The two peakswere found to bestable in phase,intensity and widths,for the last ten years.The first pulse isrelatively stronger atsoft X-rays. The firstpulse peak is narrowerthan the second peak,in both soft and hardX-ray energies. Both thepeaks show a slow riseand a steeper fall. Theratio of the pulsedphotons in the two

peaks was also found to be constant in time.

Other research themes by Paul during the year goneby included studies of QPOs in the black hole

transient XTE J1817-330; search for pulsations in thelow mass X-ray binary EXO 0748-676; and variationsin the X-ray eclipse transitions of Cen X-3.

S SridharS SridharS SridharS SridharS Sridhar’s interests lie in the theoretical domain ofgalactic astrophysics. During the year, he continuedhis work on the physics of the dynamo action dueto turbulence in shear flows.

He worked on a theory of the shear dynamoproblem for small magnetic and fluid Reynoldsnumbers, but for arbitrary values of the shearparameter. Specializing to the case of a meanmagnetic field that is slowly varying in time, explicitexpressions for the transport coefficients werederived. He and JAP student Nishant K. Singh provedthat when the velocity field is nonhelical, thetransport coefficient vanishes. They then consideredforced, stochastic dynamics for the incompressiblevelocity field at low Reynolds number. An exact,explicit solution for the velocity field was derived,and the velocity spectrum tensor was calculated interms of the Galilean-invariant forcing statistics.Forcing statistics that are nonhelical, isotropic, anddelta correlated in time were considered andspecialized to the case when the mean field is afunction only of the spatial coordinate and time.Explicit expressions were derived for all fourcomponents of the magnetic diffusivity tensor. Theseare used to prove that the shear-current effectcannot be responsible for dynamo action at smallRe and Rm, but for all values of the shear parameter.

Sridhar and his collaborators from IUCAA,Kandaswamy Subramanian and Sanved Kolekar,addressed the shear dynamo problem in the contextof “renovating flows”. In such a flow, time is splitinto discrete and finite intervals and the randomvelocity fields in different intervals are independentand identically distributed. The advantage of thisapproach is that it allows the investigation of theshear dynamo problem for arbitrary values of themagnetic Reynolds number and shear strength.

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Sridhar and Nishant Singh also derived exact solutionsof the incompressible Navier-Stokes equations in abackground linear shear flow. The method ofconstruction is based on Kelvin’s investigations intolinearized disturbances in an unbounded Couetteflow. Explicit formulae for all three components of aKelvin mode in terms of elementary functions wereobtained. It was then proved that Kelvin modes withparallel (though time-dependent) wave vectors canbe superposed to construct the most general planetransverse shearing wave. An explicit solution wasgiven, with specified initial orientation, profile andpolarization structure, with either unbounded orshear-periodic boundary conditions. The manuscriptfor this work is nearing completion.

Radio galaxies have been the primary focus ofLakshmi SaripalliLakshmi SaripalliLakshmi SaripalliLakshmi SaripalliLakshmi Saripalli’s research work. During the year, herresearch themes included studying issues related tojet stability and origin of radio galaxy types from dustdistributions in host elliptical galaxies. In collaborationwith Ravi Subrahmanyan of RRI, Ron D. Ekers of CSIRO(Australia) and Elaine M. Sadler of the University ofSydney, Saripalli worked on the characterisation ofradio galaxies in the sensitive, 1.4-GHz AustraliaTelescope Low-Brightness Survey (ATLBS). A sampleof 119 extended radio sources (ATLBS-ESS) wascompiled that yielded useful samples of high redshift,low power radio galaxies and radio sources withrestarted nuclear activity. Using the ATLBS-ESS shealso examined the potential for accessing the elusive,yet common, black hole growth and feedbackprocesses. Using the same survey, she also lookedat morphological classification of radio galaxies as afunction of 1.4 GHz total power towardsunderstanding the lifecycles of radio galaxies. Thisstudy was carried out with Kshitij Thorat of RRI.

Post-doctoral fellow SiddharSiddharSiddharSiddharSiddharth Savyasachi Maluth Savyasachi Maluth Savyasachi Maluth Savyasachi Maluth Savyasachi Malu’sresearch interests include galaxy clusters, particularlyobservations of the Sunyaev-Zeldovich effect (SZE)and radio halos, and Cosmic Microwave Background

(CMB), which includes instrument optimization andanalysis.

During the year, Malu completed the study of theSZE/Radio Halo in the Bullet cluster at 18 GHz fromdata collected in 2009. This study was incollaboration with Ravi Subrahmanyan, Mark Wieringa(Australia Telescope National Facility, CSIRO) and DNarasimha (TIFR). This study showed that the SZEhas a compact feature and the radio halo and theSZE are co-spatial – both these features are unusual,and may be signatures of energetic mergers. Toseparate the radio halo and the SZE, moreobservations were done at 18 GHz and 22 GHz inthe H168 and H75 arrays at the Australia TelescopeCompact Array in July and September 2010. Maluand his collaborators are working on separating thetwo.

The MACSurvey recently discovered several hot(T>8 keV) and X-ray luminous clusters that exhibitdisturbed X-ray morphologies. Given the connectionbetween radio halos and cluster mergers, Malu, KSDwarakanath and Ruta Kale looked into whatpercentage of X-ray selected massive clustersexhibited radio halos. They observed six differentclusters using GMRT at 235 and 610 MHz and foundthat four of these clusters exhibited either a radiohalo or a radio relic – diffuse emission associatedwith a merger. One cluster, MACS J0417, was ofparticular interest due to its unusually flat spectralindex of -0.5 (radio halos have spectral indices inthe range of -0.8 to -1.8 below 1 GHz). Thesefindings were announced at the DRP conference inRRI in March 2011. Further analysis of the data isongoing.

Another of Malu’s research themes during the yearwas exploring the Fizeau beam combination for CMBinterferometry, in collaboration with Peter Timbie ofthe University of Wisconsin-Madison. CMBobservations have been very successful in providing

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stringent limits on cosmological parameters, and thenext generation of CMB instruments aims to probethe Inflationary era through B-modes in CMBpolarization. The usual approach in this regard is thatof imaging the CMB through single dish instruments.However, the exquisite control of systematic effectsrequired to reach the sensitivity to detect B-modesis not possible with single-dish instruments; hencethe need to explore interferometry. At the same time,single-dish instruments are the ones that probe thecorrect angular resolutions required to characterizeB-modes. This poses a problem. Fizeau beamcombination offers a solution: it offers simultaneousrecovery of an image as well as visibilities in thecorrect resolution range. A manuscript describingthis technique has been prepared and will besubmitted soon.

Cluster mergers exhibit not just radio halos, butdiffuse emission far removed from cluster cores andradio relics, which are thought to be merger shocks.Malu, along with Joydeep Bagchi of IUCAA and MarkWieringa of ATNF, studied the properties of theseshocks so as to provide insight into the merger eventand enable the modeling of the dynamics of mergerevents. Abell 3376 is a cluster merger that exhibits adouble relic on either side of the shock. This doublerelic has previously been observed at 2 GHz usingthe VLA, but not at higher frequencies. Malu and hiscollaborators obtained data at 5.5 GHz and 9 GHzwith ATCA in H214 and H75 arrays to study thebehaviour of the spectral index of this double relicat higher frequencies. Analysis of data is ongoing.

During the last year, post doctoral fellow ShashikantShashikantShashikantShashikantShashikantworked on various problems in collaboration withBiswajit Paul, Biman Nath, Shiv Sethi and Tarun DeepSaini from IISc. Many of these studies areinterconnected and required the analysis of X-rayand CMB data, computer simulations, and the useof statistical techniques.

He used RXTE slew data available in the publicdomain of RXTE to map the X-Ray sky. These mapswill image the background sky in X-ray (2-60 keV).Although known point sources have been removedfrom the slew data, the group expects to detectnew faint/variable sources. According to theirestimates, with four seconds of observation at apoint in the sky, they will have enough sensitivity todetect sources with milli crab intensity. RXTE slewdata is available in two different categories – standard1 and standard 2. The difference in the twocategories is due to the different time binning andavailable spectral information. Standard 1 data isaveraged and binned every 0.125 seconds, whilestandard 2 data is averaged and binned every 16seconds. In terms of spectral difference, standard 1has no spectral information, while in standard 2 has129 spectral channels. Standard 1 data is used tomap the sky, while standard 2 data is used to removethe instrument background.

Shashikant and his collaborators first extracted lightcurve – measure of the number of photons receivedby the detector with time – from the raw data. Atthe time, the satellite was slewing continuously andhence the photon count was collected at differentpositions in the sky. The next step is to find theposition of the satellite with time. This information isprovided in the filter file which is sometimesprovided along with the observation. Photon countrate versus position maps have been generatedaround a few sources like PSR 1509-58. The abovesource was chosen as it was observed veryfrequently and thus has many slew observationsaround it in the public domain of RXTE. Computerprograms have been written to perform the abovetask, which has been automated so that several datafiles can be handled simultaneously without humaninterference.

The source of X-ray background at E#8805; 1.0 keVis mostly extra-galactic, although at lower energies

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E#8804; 1.0 keV most of the emission comes fromthe Milky Way itself. It is believed that Active GalacticNuclei contribute to most of the high energy part ofthis background. The diffuse (without resolving thepoint sources) extra-galactic part of the X-raybackground can trace the distribution of matter witha bias factor determined using the density tracedby X-rays and the actual mean density of matter. Thebias factor has been measured and is expected tobe used in X-ray background maps to put constraintson the bias parameter. An extensive literature surveyis going on along this line, though the calculation ofthe bias parameter requires some computation forwhich computer programs will be written.

Shashikant also worked on the detection of theintegrated Sachs-Wolf effect. When the CMB photonspass through the matter distribution they can be blue/red-shifted due to the gravitational potential of thematter. While entering the matter they get blue-shiftedand while leaving, they get red-shifted. This blue andred-shift would be the same if the gravitationalpotential of the matter does not change with time,which is the case in matter dominated cosmology.However, observations suggest that the expansionof the Universe has accelerated in the recent past(in terms of red-shift). This fact can be explained byassuming a component with negative pressure calleddark energy. In case of a dark energy-dominateduniverse, the gravitational potential of the matterstructures decreases with time. Thus the red-shiftwhen the CMB photons leave the matter structurewould be small compared to the blue shift whenthey entered it. This effect is known as late timeSachs-Wolf (SW) effect or Rees-Sciama (RS) effect.This net blue shift in the above SW or RS effect iscorrelated with the matter distribution and hencecan be probed by looking for the correlation of theCMB anisotropies and the matter distribution.

This work produces the maps of X-ray backgroundwhich can be used to probe matter distribution.

For the CMB, sky maps from the WMAP experimentare going to be used.

In collaboration with Tarun Deep Saini of the IndianInstitute of Science, Shashikant studied non-Gaussianity and direction dependent systematics inHST key project data.Measuring an accuratevalue of the Hubbleconstant (HO) whichrequires an accuratemeasurement ofdistances, is one of themost challenging tasksin cosmology. Manytimes systematic errorsdominate the accuracyof distancemeasurement andhence causeuncer tainty in themeasurement of HO. Ifthe systematic effectsdepend on direction,they can cause a threatto the cosmologicalprinciple, which statesthat the Universe isisotropic andhomogeneous at agiven cosmic time.Apart from systematicerrors, random errorsare also a part of anyexperiment. Due toCentral Limit Theoremwe expect theserandom er rors tofollow a Gaussian distribution. This Gaussian noisecan be used to infer parameters of interest from theobservational data. If the random errors in the data

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are not Gaussian, the inference will be biased. Thusit is essential to know the nature of the errors in thedata.

The direction dependent systematics and non-Gaussian features in the measurements of the Hubble

constant provided bythe Hubble SpaceTelescope (HST) werestudied. Measuring HOwith 10% accuracy wasone of the “KeyProjects” of the HST andit has provided the bestmeasurement of theabove so far. Newstatistical techniqueshave been derivedbased on extremevalue theory to studythe above features.

Research AssociateHarish VHarish VHarish VHarish VHarish Vedanthamedanthamedanthamedanthamedantham’swork during the yearincluded imaging withthe MWA 32Tile system,in collaboration with NUdaya Shankar and RaviSubrahmanyan of RRI,and studying the effectof astrophysicalforegrounds andimaging algorithms onimaging the EOR. In thisconnection they haveshown that using thewindowing techniqueextensively used in

spectroscopy can be very beneficial to thedetection of EOR signal which reduces the

contamination of the EOR signal by the foregroundsignals by several orders of magnitude.

They have also suggested usage of Chirp Z Transform(CZT) for imaging which decreases the stochasticnoise in images generated using the conventionalalgorithms employing Fast Fourier techniques.

Research Associate Mayuri S Mayuri S Mayuri S Mayuri S Mayuri S worked with RaviSubrahmanyan, N Udayashankar and AvinashDeshpande to explore different antenna designs forthe Aperture Array so as to optimize performancewhile eliminating or minimizing setbacks faced inconventional structures. The design currently beinginvestigated is a connected array structure capableof operating over a large bandwidth of 30 MHz to860 MHz.

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Light andmatterphysics

LIGHTANDMATTERPHYSICS

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overviewThe Light and Matter Physics (LAMP) group, which was started in1995, comprises of four motivated faculty members and theirstudents. The members of the LAMP group combine knowledgefrom atomic, molecular, linear and nonlinear optical physics to studyclassical and quantum light-matter interactions. The group takes aholistic scientific approach, where the fields of theoretical,numerical and experimental research complement one another.

There are four labs that cater to the individual needs of the LAMPmembers:

– The Laser Cooling, Light Scattering Lab

– The Ultrafast and Nonlinear Optics Lab

– The Quantum Optics Lab

– The Quantum Interactions (QUAINT) Lab

The following pages summarize the major areas of research for theLAMP group. Each member’s individual work during the last year isprovided in the next section, giving the reader a more detailedand technical description of their respective research activities.

QUANTUM OPTICS

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Quantum optics is a field in physics that appliesquantum mechanics to study phenomena involvinglight and its interactions with matter. Since the firstindication in 1899 that light may be quantized, thefield of quantum optics has witnessed significantprogress in our understanding of light-matterinteractions and microscopic systems. Today’s majorfields of interest in quantum optics include themanipulation of elemental particles like atoms, ionsand molecules and the use of quantum optics forquantum information.

LASER COOLING AND TRAPPINGLaser cooling and trapping is an area of physics thathas largely expanded over the last decade. Presently,atoms can be cooled down to extremely low kinetictemperatures (as low as 1 microK) and trapped fora time period of the order of seconds. Such controlover the motion of atoms allows researchers toprobe their behaviour more precisely than before.There are a number of techniques to cool and trapatoms of alkali elements, with the most commonlyused being the so-called Doppler cooling. It involvesthree mutually perpendicular laser beams thatintersect at the centre of the chamber. A pair ofmagnetic coils produces a magnetic field that is zeroat the centre of the chamber, and increases radiallyoutward. Using appropriate wavelength andpolarization of the laser beams, atoms can be cooledby repeated absorption and emission of light, andtrapped by an inward force arising out of thecombination of the polarized light beams and thespatially varying magnetic field. Such a system iscalled Magneto Optical Trap or MOT.

2D MOT2D MOT2D MOT2D MOT2D MOT: : : : : Researchers from the LAMP group arecontinuing their work on the construction of a 2dimensional MOT. Currently, they are involved in theprocess of installing and testing of the coils thatproduce the magnetic force in the MOT.

MOT and Quantum Logic: MOT and Quantum Logic: MOT and Quantum Logic: MOT and Quantum Logic: MOT and Quantum Logic: As electronic devicesbecome smaller and smaller, quantum effects likesuperposition and entanglement cannot be ignoredand new ways of defining the basic states of 0 and1 need to be found. To attempt quantum logicalgates, the atoms need to be cooled and trapped inoptical lattices such that the 0 and 1 states of a digitalcircuit can be mapped to internal states of the atom.The inducing of conditional transitions betweenthese states is the equivalent of a logical gate.Currently, a MOT with the capability of trappingindividual atoms is being built at RRI.

A Lattice of Ion TA Lattice of Ion TA Lattice of Ion TA Lattice of Ion TA Lattice of Ion Traps: raps: raps: raps: raps: Researchers at RRI hadproposed a novel ion trap configuration that allowsfor high precision spectroscopy measurements,quantum information processing as well as newstudies of few particle interaction systems. A scaledprototype of this trap has been built and tested withfluorescent particles in air. One or more chargedparticles can be loaded into the trap on demandand collective behaviour/interactions studied.Systematic measurements on trapped particles withthis system are under way for an experimentalunderstanding of the trap operation and followingthat a study of ion-ion interactions.

Atom Ion Molecule Experiment (AIM): Atom Ion Molecule Experiment (AIM): Atom Ion Molecule Experiment (AIM): Atom Ion Molecule Experiment (AIM): Atom Ion Molecule Experiment (AIM): Ions andatoms are trapped using different trapping principles.To manufacture a trapping scheme where both ionsand atoms at very cold temperatures can besimultaneously trapped is a major conceptual andtechnical challenge. This very objective has beensuccessfully attained by members of the LAMPgroup. Such an experiment allows for interactionsbetween ions and atoms to be studied in great detail.Initial studies that relate to the thermodynamics ofthe ion-atom combined system are at an advancedstage. The enormous increase in the interactionswithin this dilute gas ensemble will be exploited inthe near future for the synthesis of ultra coldmolecules from ultra cold atoms.

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Molecule Ion Cavity Atom Experiment (MICMolecule Ion Cavity Atom Experiment (MICMolecule Ion Cavity Atom Experiment (MICMolecule Ion Cavity Atom Experiment (MICMolecule Ion Cavity Atom Experiment (MICA): A): A): A): A): Toexpand on the possibilities opened up by AIM, anew experiment has been designed and built in thepast year. In addition to ion and atom traps,simultaneous and overlapped molecule and lighttraps have been created. The new features allowsensitive detection of the very feeble light from thetrapped molecules. The cavity will permit light signalenhancement from atoms and molecules by a factorof several thousand. Once again very novelconceptual and engineering challenges wereovercome to build the experiment. The experimentis now ready and initial experiments are detectinglow light levels signals from atoms by the cavity.

VVVVVapour Cell based Experiments: apour Cell based Experiments: apour Cell based Experiments: apour Cell based Experiments: apour Cell based Experiments: In order tounderstand the various aspects of light-atom, light-molecule interactions, several experiments havebeen performed on atoms and molecules in vapourcells. Questions such as how to switch the intensityof light in an atom-cavity system have been lookedat in great detail. The spectroscopy of atoms andmolecules in such cells was also undertaken. A veryimportant class of measurement undertaken is relatedto the preservation of the atomic state of atomsunder collisions. These experiments are done inspecial vapour cells where collision with the wallsof the cell tends to preserve certain atomic states. Itis therefore important to work on the reasons whystate changing collisions are suppressed in thesespecial coated cells. Work related to the materialproperties of these coatings was also undertaken.

ELECTROMAGNETICALLY INDUCEDTRANSPARENCY (EIT)EIT is a quantum mechanical phenomenon where,under specific conditions, an absorption line of amaterial can be cancelled changing it from opaqueto transparent at that particular frequency. To observe

EIT, two highly coherent lasers are tuned to interactwith three or more quantum states of the material.Since 1990, considerable research activity has beendevoted to the topic of EIT. RRI researchers are tryingto build a strong fundamental understanding of thisphenomenon using both theoretical andexperimental methods.

QUANTUM WALK OF LIGHTA random walk is a mathematical description of atrajectory where the successive steps are random.Classical random walks are used in search algorithmswhen the searched parameter space is random. Theyfind application in the fields of computer science,physics, ecology, economics and psychology.Quantum walks are the equivalent of random walksin quantum computing and can form a part of aquantum algorithm. Members of this division are nowinvestigating the quantum walk of light in thefrequency space.

LIGHT PROPAGATION IN RANDOMMEDIAMultiple scattering of light in random media, like fog,considerably reduces visibility. Researchers at RRIhave developed a technique for imaging in turbidmedia, which is cur rently being tested forcommercial applications like aircraft navigation.

The localisation of light in random media is aphenomenon that is not well understood. Afterextensive simulations, members of the LAMP groupare now attempting to observe localisation of lightexperimentally using ferrofluids as a medium.Ferrofluids consist of a fluid (usually water) withferromagnetic nanoparticles, that act like randomscatterers, dispersed in it. The easy manipulation ofthe nanoparticles in ferrofluids allows the quick

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testing of various possible scenarios that lead to thelocalisation of light. The understanding of thisphenomenon might open doors for future noveloptical devices.

NONLINEAR OPTICSWhen a dielectric material is irradiated with a highintensity laser beam, the polarization response nolonger scales linearly with the intensity of the appliedfield. This results in interesting modifications of therefraction and absorption behaviour of the medium.Nonlinear optics is the branch of physics thatinvestigates such nonlinear responses of materialsto electromagnetic radiation. It is a broad field ofresearch and technology, with device applicationsin telecommunications, optical storage and all-opticalcomputing. Optical switches, saturable absorbersand optical limiters are just a few examples of devicesutilizing the effects of nonlinear transmission. TheLAMP group at RRI employs pulsed laser z-scan anddegenerate four wave mixing (DFWM) to investigatethe nonlinear optical properties of various types ofmaterials, including nanopar ticles andnanocomposites. To study the temporal evolutionof the nonlinearity the group uses femtosecondpump-probe spectroscopy. Other supportingexperimental techniques employed for theseinvestigations are cw z-scan, absorptionspectroscopy, photoluminescence andphotoacoustics.

LASER INDUCED PLASMASLightning is a beautiful (and often scary) example ofhow Nature can create plasma. Today, thetechnological evolution of lasers allows researchersto generate plasma routinely in their labs. Plasma (thefourth state of matter) can be generated from a solid,liquid or gas sample using high power pulsed lasers.

Such plasmas are called laser induced plasmas andthey find application in several technological fields.In material science Pulsed Laser Deposition (PLD) isa commonly used technique, where the laserinduced plasma acts as the source of material to becoated on a suitable substrate for producing thinfilms and nanoparticles of various compositions.Laser Induced Breakdown Spectroscopy (LIBS), theoptical emission spectroscopy of laser inducedplasma, is a powerful technique that providesimmediate elemental analysis of any materialregardless of its physical state. LIBS is widely usedfor the detection of heavy metals in soil, aerosolcharacterisation, cultural heritage elemental analysis,process control in industry, and space exploration.Laser induced plasmas are also used in the field ofmedical diagnosis and surgery, laser ignition,propulsion and fusion.

Researchers from the LAMP group routinely conductexperiments to study the time evolution and spectralcharacteristics of plasmas generated byfemtosecond and nanosecond lasers. At presentmetallic solids are being used as irradiation targets,and the experiments are performed in vacuum aswell as under ambient pressure conditions.

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ongoingresearch

Andal NarayananAndal NarayananAndal NarayananAndal NarayananAndal Narayanan’s research during the year included the study ofthe coherent Microwave Optical Double Resonance (MODR)phenomenon using a home-built microwave cavity and a diluteatomic vapour of rubidium atoms. In collaboration with her projectassistant TM Preethi and M Manu Kumara and K Asha of MysoreUniversity, Narayanan used the cylindrical microwave cavity at 3GHz that was built and characterised during the last academicyear. Narayanan’s research using this cavity was to understand thenature of correlation transfer between two regimes of theelectromagnetic spectrum. These correlations are generated initiallybetween an atom and the microwave field. It is then transferredto between the same atoms and an optical f ield. TheElectromagnetically Induced Transparency (EIT) effect was usedto induce the interaction between the atoms and the microwaveand optical fields.

The results of these experiments include the finding of quantumoptical effects that depend on the relative phase between themicrowave and optical fields. It was also found that these phasesensitive changes occur on a non-linear optical absorptionphenomena. These findings could have potential use in makinglogical gates in the optical domain that are controlled by a phasechange in the microwave domain.

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The cavity frequency was selected to match theground hyperfine separation in the 5 S(1/2) manifoldof 85Rb. This transition is a magnetic dipole transitionand is traditionally used for Rubidium atom basedclock frequency standard.

Other research carried out by Narayanan includesexperiments with room temperature Rubidium atomsin a vapour cell, where results of interacting darkstates in Rubidium 87 and Rubidium 85 werecompared. An experimentalsignature is found to uniquelyidentify interacting superpositionstates of internal levels ofRubidium. The experimentalsignatures of two Rubidiumisotopes were compared toidentify the role of Doppler Effect.In Rubidium 87, where the levelseparation is larger than theDoppler width at roomtemperature, the interactionbetween the dark states occursonly at select detunings. Thus, inthese systems, this effect serves asa directional frequency fi lteroperating at optical frequencies.This research was carried out in collaboration withPreethi, researchers from Mysore University and PSunil and Umakant Rapol from IISER in Pune.

Narayanan and J Vijay from BITS, Goa carried outdressed state and density matrix analysis for bothN-level and tripod-level schemes in Rubidium wheninteracting with both microwave and optical fields.The N-level scheme’s simulation agreed qualitativelywith the experimental results. The results of thetripod-level scheme are currently being discussedwith Jason Twamley of University of Macquarie,Sydney, and his colleagues.

Sadiq RangwalaSadiq RangwalaSadiq RangwalaSadiq RangwalaSadiq Rangwala’s research interests span quantuminteractions, ultra cold molecules, ion trapping andatoms and molecules in external fields.

In the previous year, Rangwala and his group hadproposed a model for an ion trap that was threedimensionally symmetric. During the year gone by,he and his students constructed a working prototypeof the model and conducted several tests on it,including trapping particles of fluorescent powders.

Research using the prototype is ongoing and will belargely driven by students. This prototype could beof tremendous significance in relation to harmonicoscillators.

The understanding of the ion atom experiment,which has several very original components, hasbeen the primary focus of experiments during theyear. Rangwala and his collaborators worked on thedesign considerations of an experimental apparatusand technique that simultaneously traps ions andcold atoms with spatial overlap. This apparatus canhelp study ion-atom processes at temperaturesranging from hot to ultra-cold – an area with respectto cold trapped atoms that has largely been

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unexplored. The ion trap and atom traps arecharacterized independently of each other. Thesimultaneous operation of both and the experimentalsignatures of the effect of the ions and cold-atomson each other were studied. Studies are currentlybeing conducted to address the issues ofsympathetic cooling of ions by atoms and thepossibilities of molecule formation, among others.

Over the last couple of years, Rangwala and his teamhave worked on putting together an experimentcapable of trapping cold atoms, cold molecules,cold ions and photons. This experiment will allowthem to laser cool Rb, K, Cs and Ca+ ion. Theseexperiments will target the Fabry-Perot cavity basedon the detection of trapped ultra-cold molecules.It is hoped that such an experiment allows theflexibility to perform a large class of experiments inAtomic, Molecular and Optical Physics. A prototypeof this experimental design was constructed inJanuary-March 2011 and its various key features, withthe exception of the ion trapping part, have beensuccessfully tested. It is believed from ongoingexperimental results that the light emitted into thecavity mode is stimulated, but further studies arerequired to confirm this hypothesis. An importantfeature is that light from cold atoms is being dumpedinto the cavity, allowing the efficient measuring ofthe signal.

As part of his work in the area of anti-relaxationcoatings for alkali metal vapour cells, Rangwalacontinued his research into paraffin coatings withpositive and negative logic switching experimentswith atoms in paraffin-coated cells. The mainchallenge with these experiments has been couplinglight into the cavity mode when there is paraffin inthe cavity mode. However, this study has thepotential to help infer the role of stimulated emissionin the system.

Measurements were also made to determine thedensity of rubidium dimer vapour in paraffin-coatedcells. The number density of dimers and atoms insimilar paraffin-coated and uncoated cells wasmeasured by optical spectroscopy. Due to therelatively low melting point of paraffin, a limitedtemperature range of 43-80ºC was explored, withthe lower end corresponding to a dimer density ofless than 107 cm3. With a one-minute integration time,sensitivity to dimer number density of better than106 cm3 was achieved.

In addition to the cutting edge experimentalprograms in the QUAINT Lab, the lab also has aparallel programme of simulation of the experimentalsystems to gain an even better understanding ofphysics. Examples of such simulations include:

1. Ion traps and multiple ions in ion traps

2. Ion atom interaction (scattering) and thetrapped ion trapped atom problem

3. Atoms in cavities

4. Molecular dynamics

RRRRReji Philipeji Philipeji Philipeji Philipeji Philip’s research interests cover laser-inducedplasmas and optical nonlinearity of nanostructures.He continued his studies in LIBS (laser-inducedbreakdown spectroscopy) and temporal dynamicsof the plasma plume, from the solid targets carbon,copper, aluminium, and zinc, kept at differentvacuum pressures. Laser pulses of 8 ns width (at532 nm and 1064 nm) were used for generatingthe plasma. A few measurements were conductedin nitrogen ambience as well. Philip is planning torepeat these measurements with ultrafast (100 fs)laser pulses, with which different dynamics areexpected.

His research during the year also included opticalnonlinearity studies in semiconductor quantum dots,ferromagnetic media, piezoelectrics and conjugated

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polymers. Philip and his collaborators determinedthe existence of surface states in doped ZnOnanostructures from an NLO measurement andobserved broadband optical limiting in high surfacearea noble metal nanosponges.

Quantum computing is one of Hema RamachandranHema RamachandranHema RamachandranHema RamachandranHema Ramachandran’sresearch interests. She has conducted boththeoretical and experimental work in the field ofquantum walks. Her research on quantum logic isbeing pursued on two fronts – using light and atoms.

Building on her previous work, which demonstrateda four-step quantum walk of light, during the pastyear she and her students succeeded in impartingcontrolled phase shifts to the walker (light) throughan acousto-optic interaction. This electronicallycontrolled implementation permits rapid and precisecontrol, and can be adapted to single-photon walkswith little effort.

She and her students are also investigating the useof atoms for quantum logic, where atoms, insuperpositions of different electronic states, formthe qubits, and their controlled transition is broughtabout by light. Towards this, they devised a schemeusing the 5S1/2, 5P3/2 and 5D5/2 levels of Rb.Exciting the 5D5/2 level required and tuning lasersappropriate for this have been completed, and thehyperfine structure of 5D5/2 level has been mapped.They are now attempting a C-NOT operation using acascaded scheme. Once a C-NOT operation hasbeen demonstrated using atomic vapours, the samewill be demonstrated using single atoms. For this, asingle-atom trap is being built. The design of thevacuum chamber and the lens holder has beenoptimized, and these have been built and tested.

Another of Ramachandran’s research themes waslight in random media. Light propagation through twokinds of random media formed the subject of herresearch. The first is fog, and the aim has been toimage through it. The second material is a ferrofluid,

which is a random suspension, in liquid, ofnanospheres that are magnetic. The application ofan external magnetic field alters the arrangement ofthe nanospheres, leading to interesting opticalcharacteristics.

During the previous year, Ramachandran and her teamhad planned an experiment for imaging throughturbid media, with the specific application of usingthe technique for navigation. A proof-of-principleexperiment envisaged placing a polarized lightsource on top of a high tower (a TV tower in Rennes,France), and imaging this light source through fogusing polarization discrimination in a nearbylaboratory. Preliminary work has been carried out. Asource, with the requisite characteristics (wavelength,intensity, polarisabil ity, continuous outdooroperation) was tested atop the TV tower; it has beenfunctioning for several months, in all types of weather.Data collected at the lab has to be analysed. Thisstudy was done in collaboration with Mehdi Alouiniand Julien Fade of University of Rennes and FabienBretenaker of University of Paris.

The work on the unusual transmission and reflectionof light by ferrofluids was continued. On theexperimental front, a large parameter space wasinvestigated in a systematic manner, and at differentwavelengths of light, with the experiment beingautomated so as to obtain millisecond timingaccuracy. On the theoretical front, analyticalexpressions for optical parameters were derived andthe possibility of coherent Dicke scattering examined.Inferences from these studies include the belief thatferrofluid is a novel medium, where one can imposeweak spatial order, that may be tuned, by means ofan externally applied magnetic field. This, along withthe weak dissipation that is present in the medium,would provide a “Lossy Anderson-Bragg” (LAB)cavity where the interplay of random multiplescattering, Bragg scattering and loss would lead to

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unusual effects, like the simultaneous decrease intransmission and reflection of light.

Numerical simulations were then performed, where,using the method of invariant imbedding, thetransmission and reflection coefficients werecalculated as a function of the wavevector for a rangeof disorder and loss.

At the Bragg condition, a simultaneous dip in thetransmission and reflection was observed, confirmingthe picture of the LAB-cavity. This work was carriedout in collaboration with M. Shalini of MumbaiUniversity, D. Mathur of TIFR, Divya Sharma of BITSPilani (at Hyderabad), and AA Deshpande and NKumar of RRI.

Building on recent work on light emission by carbonnanotubes (CNTs), Ramachandran and hercollaborators noticed the formation of bubbles inthe surrounding fluid, which then could be trappedat the tweezer focus. This bubble formation wasattributed to the photo-thermal heating of the CNTsand its vicinity, leading to the expulsion of hot gasfrom within the CNTs and vaporisation of the

immediate surrounding fluid. They studied thedynamics of these bubbles (in experiments carriedout at TIFR, Mumbai), and have distinguishedbetween gaseous and vaporous bubbles.Numerically solving the hydrodynamic equations, themechanism of the formation of bubbles of eitherkind has been elucidated, and has shown howextremely high temperatures may be reached. This

confirms their earlier surmise of hot-spots in the context of white lightgeneration from CNTs.

Collaborators for this study, whichhas now been published, includedDeepak Mathur of TIFR and his teamand Aniruddh Pandit of UDCT.

Post Doctoral Fellow J SolomonJ SolomonJ SolomonJ SolomonJ SolomonIvanIvanIvanIvanIvan’s field of interest is the quantuminformation theory. During the year,his work on Bosonic Gaussianchannels was completed and adetailed analysis on the operatorsum representation of single-modeGaussian channels appeared in thearXive. Ivan worked withKrishnakumar Sabapathy and R Simon

of the Institute of Mathematical Sciences (IMSc),Chennai. Research into the relationship betweennonclassicality and entanglement in the non-Gaussiancontext was also completed in collaboration withseveral researchers across the globe.

Other areas of study for Ivan included studying therobustness of non-Gaussian entanglement. Theresults of this study indicate that non-Gaussianentanglement is more robust against Gaussian noiseand refute the conclusions of Allegra et al. This workwas also done in collaboration with Sabapathy andSimon of IMSc.

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SOFTCONDENSMATTER

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overviewThe Soft Condensed Matter (SCM) group, formerly known as theLiquid Crystals group, concentrates its research activities in thearea of liquid crystal synthesis, characterisation and other analysisof their physical properties. The group recently expanded itsactivities to investigate other soft condensed matter like polymers,colloids, amphiphilic systems and nanocomposites. Theoretical andexperimental research today includes the well established area ofl iquid crystal synthesis and characterisation as well aselectrochemistry and surface science, liquid crystal displays,rheological studies of soft condensed matter and biophysics. Theresearch environment of the SCM group is highly interactive withconstant knowledge sharing and exchange of ideas amongchemists, electrochemists, condensed matter physicists, theoreticalphysicists and members with statistical physics expertise.

The following pages summarize the major areas of research for theSCM group. Each member’s individual work during the last year isprovided in the next section, giving the reader more detailed andtechnical description of their respective research activities.

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LIQUID CRYSTAL SYNTHESISA liquid crystal (LC) is a liquid whose molecules areregularly arranged in one or two dimensions suchthat it exhibits some optical properties associatedwith crystals. LCs exist in the so-called mesomorphicstate, or a state of matter between liquid and solid.A mesogen is the fundamental unit (or molecule) ofa LC that is responsible for the structural orderobserved in these substances. Typically, LCmolecules consist of a rigid and flexible part. Thefirst one gives rise to the crystalline properties, whilethe second causes the fluidity.

There are several varieties of liquid crystals. Theimportant classifications are based on the shape ofthe molecules, their orientation, and nature of thematerial. Nematic LCs have their molecules arrangedin loose parallel lines, while Smectic LCs havemolecules that are aligned in a series of layers, withthe axes of the molecules perpendicular to the planeof the layers. Calamitic LCs have the so called rod-like mesogens while discotic LCs have disk-likemesogens. There are also a class of LCs synthesisedwith bent-core or banana shaped mesogens.Thermotropic LCs exhibit phase transition into LC astemperature changes. Lyotropic LCs phase transitionis a function of both temperature and mesogenconcentration in a solvent.

LCs are primari ly known for their extensiveexploitation in electro-optical display devices suchas watches, calculators, telephones, personalorganisers, laptop computers and flat paneltelevisions. They also have diverse applications inchromatography, spectroscopy, holography,temperature sensing, as solvents in chemicalreactions and more.

The Organic Chemistry Lab at RRI is involved in thesynthesis and characterisation of a wide range ofliquid crystals. More than 700 compounds with bent-core or banana-shaped molecules have been

synthesised andcharacterised with someof them exhibiting novelmesophases (the phasebetween crystalline andisotropic l iquid) andinteresting properties likespontaneous electricalpolarisation. The lab isequally active in thesynthesis of novel disc-likemesogens that haveimpor tant electronicand optoelectronicproperties. Collaboratingwith other members of theSCM group, the OrganicChemistr y Lab of tensynthesises compounds that exhibit specific physicalproperties like ferroelectric, antiferroelectric orcolumnar phase as well as oligomeric and polymermesogens or compounds with novel metallo-mesogens with magnetic properties. The lab isequipped with polarising microscope, differentialscanning calorimeter, digital micropolarimeter,infrared spectrophotometer, UV-Visiblespectroscopy, elemental analyser, in addition to basicequipments required for chemical synthesis.

PHYSICAL MEASUREMENTSMembers of the SCM group at RRI investigate phasetransitions, structure, molecular organization andphysical properties of thermotropic liquid crystalswith rod-like, disc-like and bent-core banana shapedmolecules. The magnetic properties of liquid crystalsand their nanocomposites are also currently beingstudied. Nanocomposites (nanoparticles – liquidcrystal composites) is an active area of research forRRI. Dispersion of metallic, magnetic or ferroelectric

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nanoparticles in differentliquid crystals are verypromising for novel futuredevice applications. Oneof the major challenges inthe field right now is theunderstanding of themechanisms of selfassembly of nanoparticlesso that reliable control ofthe dispersion can beachieved with sufficientrepeatabil ity for hightechnology applications.The main advantage of LCsis their responsiveness toexternal stimuli like electricand magnetic field which

provides more control on the dispersion processand tunability of the nanocomposites. Currently, theSCM group is working with BaTiO3, goldnanoparticles and carbon nanotubes.

Of ten, novel measurement techniques aredeveloped and used to measure the responses invarieties of liquid crystals with higher precision andaccuracy. Typical measurement techniques involvedielectric spectroscopy, optical birefringence,polarizing optical microscopy and others.

LIQUID CRYSTAL DISPLAYS (LCDs)LCD technology is the most common andwidespread display technology in the world today.LCDs are literally everywhere, in our cell phones,televisions, laptop computers, video players, digitalwatches, calculators, gaming devices! They are muchthinner, lighter, portable, more reliable and drawmuch less power compared to the old displaytechniques. Research activities at RRI focus on thedevelopment of new addressing techniques of the

drive electronics in LCDs with passive matrix thatwould fur ther reduce power dissipation andhardware complexity. RRI has applied for 16 US andEuropean patents related to its research activities.Today, a multiline addressing technique, inventedhere, is extensively used in LCD electronicsworldwide. The LCD lab has basic facilities tofabricate LC cells and small size prototype displaysfor testing purposes.

RHEOLOGY AND LIGHT SCATTERINGSTUDIESRheology studies the deformation and flow of matterwhen different kinds of stress are applied to thesample. Rheology builds on top of the classicalelasticity and Newtonian fluid mechanics to extendour understanding to materials whose mechanicalbehaviour cannot be described with these classicaltheories. It is used to make predictions for themechanical behaviour of a material based on itsmicroscopic structure. Rheology has importantapplications in engineering (development and useof polymer materials), geophysics (studies of mud,snow, magma, etc) and physiology (blood flowmeasurements).

Researchers at RRI use rheology and light scatteringtechniques to study the dynamics and variousresponses in soft glassy materials. Examples of theseare various concentrated suspensions, emulsions andgels used widely in industry. Soft glassy materialsexhibit slow dynamics and serve as excellent modelsystems in the understanding of non-equilibrium glasstransitions in hard condensed matter. A mix ofsynthetic clay suspended in water called Laponiteis currently the material of choice for the group’sresearch. The same material is used to studyinstabilities at the interface that occur when a lowviscosity fluid (water) is injected into a more viscous

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one (aging clay suspension). Such studies areimportant for various technological processes likepercolation of oil through porous rocks.

Amphiphilic compounds consist of molecules thathave both hydrophobic and hydrophilic parts. Athigh enough concentrations the amphiphilicmolecules star t to form micelles or vesicles(amphiphilic molecules group together in various 3Dstructures arranged with their hydrophilic part facingthe solvent). Amphiphilic block copolymers are atype of copolymer that is used in pharmaceuticalapplications for sustained-release technologies orgene delivery. Because of their amphiphilic naturewhen suspended in aqueous solution they start toform micelles. The hydrophobic core of the micellesserves as a reservoir for hydrophobic drugs. Pluronictriblock copolymer is a type of amphiphiliccopolymer that is extensively studied by researchersat RRI because of its enormous potential forcontrolled drug delivery applications. Rheologytechniques are utilised to study its stability understress and strain, and determine the temperature-concentration phase diagram. Dynamic lightscatterometry techniques are used to extract thesize distribution in the sample.

ELECTROCHEMISTRY AND SURFACESCIENCEThe Electrochemistry and Surface Science lab at RRIis actively involved in various research activitiesrelated to:

(i) electron transfer processes of redoxmolecules;

(ii) electrical and photoconductivity of dopedcolumnar discotic liquid crystals;

(iii) electrochemistry of surfaces and interfacesformed by self-assembled monolayers andother organic thin films;

(iv) electron transferprocesses andconductivity in bio-molecules onelectrode surfaces;

(v) characterisation ofconducting polymernanostructures. Thelatter can lead topotential applicationsin sensors, energyconversion devicesand fuel cells. The labis equipped withmodern facilitiesallowing for a widerange ofmeasurementtechniques to beapplied. Some of theextensively usedequipment includeatomic forcemicroscope, scanningtunnellingmicroscope,electrochemicalquartz crystalmicrobalance,frequency responseanalyser and manymore.

BIOPHYSICSThe Biophysics lab is part of the SCM group thatwas started just two years ago. Today, it is a self-sufficient lab where cells can be grown, manipulatedand analyzed. The primary research focus in theBiophysics lab is the understanding of cellular

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dynamics l ike forcegeneration, movement andtranspor t processes. Avariety of cells is grown inthe lab and tested usingnovel experimentaltechniques. Axons are apar t of the neuron thatextends from the neuron’scell body. In the majority ofcases, axons are found totransmit electrical pulses.They are effectively thetransmission lines of thenerve system. Members ofthe Biophysics lab arecurrently involved in thedesign, construction andintegration of anexperimental set up thatcan provide insight into thedeformations anddynamics in axons.Experimental research ofthe patterning anddifferentiation of stem cellsis another important activityof the lab.

PHASEBEHAVIOUR OFSURFACTANTSSurfactants are amphiphilic

organic compounds that allow easier spreadingbetween two liquids or a liquid and solid. They arewidely used in our everyday life as detergents,foaming agents and emulsifiers. The researchendeavour of the SCM group is focused on

fundamental understanding of the phase behaviourof various surfactants with equal emphasis oninterpretation of experimental results anddevelopment of analytical models.

Lipids are a group of molecules that form animportant structural component of cell membranes.Their main biological function includes energy storageand “signalling”. A lipid bilayer is made up of twolayers of lipid molecules to form a continuous barrieraround the cell called membrane. The cellmembranes of almost all living organisms and manyviruses are made of lipid bilayers. Recently, aphenomenological theory of phase transition in lipidbilayers has been formulated by researchers at RRI.A study of the structural changes induced in lipidbilayers bound to toxins and the development of anew technique to extract their electron densityprofiles is underway.

LIQUID CRYSTALS THEORYTheoretical work is conducted by many of the SCMgroup members parallel to their experimentalprojects. Analytical models are being developed forthe behaviour of various liquid crystals, membranesand polymers.

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ongoingresearch

Sandeep KumarSandeep KumarSandeep KumarSandeep KumarSandeep Kumar’s research interests include the design, synthesisand applications of various liquid crystalline materials and thestructure-property relationship in these self-assembling supra-molecular architectures. During the year, he furthered his workin the synthesis, characterisation and understanding of severalnew mesogens through individual and collaborative research.

His work included the study of discotic liquid crystalline geminiampiphiles. The chemical structures of these salts were examinedby 1H NMR, IR , UV, MS, and elemental analyses. Themesomorphic properties of these discotic dimeric salts wereinvestigated by polarizing optical microscopy, differentialscanning calorimetry, and X-ray diffraction studies. These geminidimers with bromide as a counter ion were found to exhibitliquid crystalline behaviour over a wide temperature range anddisplay ionic conductivity in the range of 10-6 to 10-5 S/m. Itwas found that these materials tend to form monolayer at theair-water interface.

The incorporation of photorefractive molecular units, such ascarbazole, into anisotropic materials (liquid crystals) may offer

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many advantages over conventional electrical polingof photorefractive polymers. Keeping this in mind,Kumar and his collaborators (M Manickam, P Iqbal,N Spencer, PR Ashton, KJ Donovan and JA Preece)synthesised and characterised a series of symmetric3,6 disubstituted carbazole derivatives with well-known biphenyl and triphenylene liquid crystallinemoieties. Though the pure compounds are notliquid-crystalline, they may be of interest in the fieldof photorefractivity.

In collaboration with KA Suresh and group from RRI,physical studies on liquid crystalline materials wereconducted. One of these studies included that ofthe Langmuir monolayer of a novel moleculecontaining a dimer of disk shaped moiety at air-waterinterface. The monolayer exhibited the coexistenceof condensed and gas phases at a large area permolecule, which on compression transformed to auniform condensed phase at lower area permolecule and collapsed at an even lower area.

The monolayer film transferred by the Langmuir-Blodgett technique onto a hydrophilic siliconsubstrate was studied using an atomic forcemicroscope. These studies showed that the collapsepressure increased with an increase in thecompression rate. Studies on the effect oftemperature on the collapse pressure of thetriphenylene-dimer monolayer showed that thecollapse pressure decreased with increase intemperature. The analysis of the relative area loss asa function of time in the collapse region suggestedthat the monolayer collapses by the formation ofnuclei of three-dimensional crystallites.

ArArArArArun Run Run Run Run Royoyoyoyoy is part of the Soft Condensed Matter groupand his research interests include phase transitionsand electro-optic properties of liquid crystals andthe physics of nanomaterials and nanocomposites.

One of his research themes during the year was thestudy of the blue phase LCD. The electro-optic effectwith blue phase has several advantages: It has sub-

millisecond response to an electric field; unlike theconventional LCD, response times are independentof thickness of the display cell; and it does notdemand the alignment of liquid crystal molecules atthe inner surfaces of the cell. The quick response ofblue phase LCD can help simplify the circuitnecessary to drive the display. However, the highand narrow temperature range of blue phase posesa challenge with regard to its use in practical devices.Roy, in collaboration with Sandeep Kumar and TNRuckmongathan, is looking at fabricating a blue phaseLCD cell based on literature survey to gain insight onthe working of the cell.

Roy conducted experimental and theoretical studiesinto randomly polarised smectic A phase exhibitedby bent-core molecules. He and his collaboratorsrepor ted experimental studies on a newlysynthesised bent-core liquid crystal exhibiting partialbilayer SmAdPR and SmAdPA phases. Though theSmAdPR phase appears to be optically uniaxial, asthat of the Smectic A phase, the following distinctiveproperties of the former were observed:

• A current peak associated with a polarisationreorientation process under the application of atriangular wave voltage

• Large variation of the effective birefringence ofthe planarly oriented sample with the applied in-plane electric field

• The presence of a strong dielectric mode

A simple theoretical model was developed todescribe the properties of the SmAPR phase andthe transition from the SmAPR to the SmAPA phase. Itwas proposed that the above characteristicproperties of the SmAPR phase arise due to thestrong coupling between the transverse polarisationand the transverse polar order of the bend directionsof the bent-core molecules in the layers.

Roy worked on this along with BK Sadashiva, postdocfellows Meenal Gupta and Soma Datta and S Radhika.

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Using a new electro-optic technique, Roy and Dattainvestigated the critical behaviour of the electroclinicresponse in the chiral Smectic A* phase in the vicinityof the transition from the Smectic A* to Smectic C*phase. The technique took into account thenonlinearity of the electroclinic response close tothe transition temperature and allowed for themeasurement of the electroclinic coefficient,relaxation frequency and the nonlinear coefficientof the electroclinic response. The electrocliniccoefficient diverges with decreasing temperature asthe transition temperature is approached. The

measured critical exponent agrees well with thepredictions of mean field Landau theory, though themeasured nonlinear coefficient was found to betemperature dependent contrary to the usualassumptions of the mean field Landau theory.

Roy’s research also included studying the physicalproperties of various liquid crystal compounds. Thecolloidal dispersions of nanoparticles in liquidcrystals were investigated experimentally using thethermotropic liquid crystalline compound 4-n-octyloxy 4-cyanobiphenyl (8OCB) doped withBaTiO3 nanoparticles. It was found that the physical

properties of these dispersions vary considerablydepending on the method of preparation of thedispersions. It was also found that aging the sampleimproved dispersal of the nanoparticles in the hostliquid crystal, and hence enhanced the stability ofthe dispersions. This study was in collaboration withR Pratibha, Meenal Gupta and Ipsita Satpathy.

Roy and Gupta, in tandem with Veena Prasad andNG Nagaveni from the Centre for Liquid CrystalResearch, synthesized and repor ted themesomorphic properties of five new series of azofuctionalised phasmid-like compounds formed by

covalent bonding. The compoundscomprised both symmetric and non-symmetric molecules, and mostwere found to be liquid crystallinewith unusual behaviour. Theyexhibited mainly nematic, columnarand smectic mesophases. In a fewcases, higher order mesophaseswere also observed. Thesemesophases were studied usingpolarizing optical microscopy(POM), differential scanningcalorimetry (DSC) and X-raydiffraction (XRD). Based on theresults, the team proposed a modelfor the molecular arrangement in thecolumnar phase as a centre

rectangular.

Roy and his collaborators, R Pratibha, S Radhika,Meenal Gupta and BK Sadashiva from RRI, investigatedthe phase behaviour and physical properties of anew homologous series of compounds consistingof hockey-stick shaped molecules synthesised in RRI’schemistry laboratory. To characterize the differentphases, various experimental studies wereconducted on these compounds, including opticalobservations on confined samples and freestandingfilms; miscibility studies; X-ray diffraction studies; and

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dielectric spectroscopy. These studies showed thatthe compounds exhibited unusual tilted lamellarphases. The results will be included in the manuscriptcurrently under preparation.

TN RuckmongathanTN RuckmongathanTN RuckmongathanTN RuckmongathanTN Ruckmongathan runs the Liquid Crystal DisplayLab where his group is focused on the developmentof new addressing techniques to drive liquid crystaldisplays. Reduce power dissipation and hardwarecomplexities of drive electronic in LCDs are some ofthe goals of his research work. He is alsocollaborating with Sandeep Kumar and Arun Roy,to study blue phases in liquid crystals with an ultimategoal of fabricating a blue phase LCD cell.

Building on his recent work on cross- pairing of selectand data voltages to generate thousands of RMSvoltages with just a few voltages in a line-by-lineaddressing technique; Ruckmongathan is exploringthe possibility of doing the same when the displayis driven by selecting multiple address lines. Thehardware complexity of data drivers that are usedto drive a matrix display increases with the numberof grey shades. The aim of this research is to reducethe hardware complexity of data drivers in RMSresponding LCDs.

In addition to these topics, Ruckmongathan iscontinuing his work on finding a simple and elegantmethod for 2-D addressing of matrix displays.

R PratibhaR PratibhaR PratibhaR PratibhaR Pratibha’s research interests lie in the fields of liquidcrystals and nanocomposites.

Bent-core mesogens have the ability to combinepolar order and chirality and form several novelphase structures that are of considerable interest.Further, variation of the bent molecular architecturefrom a symmetric to an asymmetric one, can giverise to very different physical properties. Pratibha,along with Meenal Gupta and Arun Roy has carriedout detailed experimental studies on a new seriesof compounds made of asymmetric bent-coremolecules recently synthesised by S Radhika and B

K Sadashiva. Based on optical observations on bothconfined samples and freestanding films, miscibilitystudies, X-ray diffraction studies and dielectricspectroscopy, they have shown that a lamellar phaseexhibited by these compounds has a new and thusfar unreported type of smectic structure.

Another one of Pratibha’s research topics during theyear was related with l iquid crystal – goldnanoparticle composites. The surface plasmonresonance of metal nanoparticles is known to bevery sensitive to the size and shape of the particlesand the surrounding dielectric environment. Herearlier studies using gold nano spheres had shownthat the surface plasmon resonance wavelength canbe tuned as a function of the concentration of theparticles in the liquid crystal matrix. Pratibha and UmaMaheswari have now extended this study usingnanoparticles with elongated and anisotropic shapeswhich have the added advantage that their aspectratio can be used as an additional tunable parameterfor practical applications. The work involved thesynthesis and characterisation of the goldnanoparticles using optical absorption spectroscopyand TEM. Detailed optical and dielectricmeasurements have also been carried out on thesecomposites.

Liquid crystals made of bent-core molecules canexhibit polar ordered smectic phases that areferroelectric or antiferroelectric in nature and exhibitelectrooptic switching behaviour. However,transitions between such switchable phases, is notcommon. To understand the molecular origin of thedielectric relaxation processes, Pratibha and ArchanaAmatya have carried out dielectric studies on a bent-core liquid crystal exhibiting a transition betweentwo such switchable phases.

Ranjini BandyopadhyayRanjini BandyopadhyayRanjini BandyopadhyayRanjini BandyopadhyayRanjini Bandyopadhyay runs the Rheology and LightScattering Lab. Her research group employs dynamiclight scattering, rheology, optical imaging or acombination of these techniques to study the

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structures, dynamics, stability and mechanicalresponses of a diverse range of soft materials.

Her research on the jamming transition in triblockcopolymer solutions and in triblock copolymer-anionic surfactant mixtures included conductingphoton correlation spectroscopy and rheologicalmeasurements to study the microscopic dynamicsand mechanical responses of the solutions andmixtures. Increasing the concentration of triblockcopolymers in an aqueous solution results in a sharpincrease in the sample viscosity. This is understoodin terms of the changes in the aggregation andpacking behaviours of the copolymers and theconstraints imposed upon their dynamics due toincreased close packing. Adding suitable quantitiesof an anionic surfactant to highly viscous copolymersolutions results in a decrease in the sample viscosityby several decades. This indicates that the shapeanisotropy and size polydispersity of the micellescomprising mixtures cause dramatic changes in thepacking behaviour, resulting in sample unjamming andthe observed decrease in viscosity. Bandyopadhyayand her collaborator Rajib Basak plan to use thisresearch to study the potential of Pluronic as a drugdelivery agent.

The glassy phase is an out-of-equilibrium, disorderedstate of matter that originates due to the jamming ofthe constituents of the system. In this jammed orfrozen state, the motion of the constituents appearsto be arrested and the dynamics of the systemcontinues to slow down with time – a phenomenonknown as aging. Colloidal glasses are soft glasses(i.e. they have a very low shear modulus whencompared to hard glasses) that exhibit all theproperties typically expected in hard glassy materials.This research targeted various issues regarding glassformation in the context of colloidal suspensionsprepared by dissolving a glass former (Laponite – asynthetic hectorite clay) in highly deionized water.In colloidal glasses, the constituent particles or

clusters are trapped in cages formed by theirneighbours, which restricts their motion and slowsdown their dynamics. These caging dynamics werestudied through Dynamic Light Scattering (DLS)experiments.

When a low viscosity fluid is injected into a moreviscous fluid, a fingering instability called the SaffmannTaylor instability results. The understanding of thisinstability and the resulting finger patterns areimportant due to the ubiquity of such processes intechnological applications, such as in the percolationof oil in porous rocks. The main purpose of thisproject is to investigate the physics behind thepattern formation at the quasi-two dimensionalinterface between a Newtonian fluid (water) andan aging non-Newtonian fluid (an aqueoussuspension of the synthetic clay, Laponite). It wasfound that the fractal dimensions of the patternschange significantly as the age of the Laponitesuspension changes. This research was done incollaboration with Debasish Saha and PawanNandakishore from RRI and Rama Govindarajan fromJNCASR.

Cornstarch suspensions consist of irregular disk-shaped particles of average size 14 microns. Abovea concentration-dependent critical shear rate,cornstarch suspensions shear thicken. It is widelybelieved that at even higher shears, cornstarchsuspensions form nonequilibrium shear bands.Bandyopadhyay and her team performed systematicrheological measurements to look at the effects ofrotational shears on the viscosities of thesesuspensions for density-matched cornstarchsuspensions that range between35 wt.% and 42 wt.% in concentration. They alsostudied the dependence of the shear bandingphenomenon on the thickness of the sample andfound that with increasing thickness, the critical shearrate for forming shear bands increases.

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In collaboration with Abhishek Dhar, SanjibSabhapandit and Prakhyat Hejmady, Bandyopadhyaystudied size segregation in a quasi 2-D granularcolumn. The dynamics of a large particle (intruder)in a 2-D vibrated column of small grains was studied.It was found that the intruder, which is initially keptat the bottom, rises upward when the column isvibrated. This particle was tracked as it movedupward using high speed video imaging to estimateits dynamics, including how relative density effectsthe rise time, velocity and acceleration of the largeparticle.

Building on earl ier research,Bandyopadhyay and her teamimproved the design of the falling ballviscometer set up earlier so that the ballis now released via an electromagnet-based mechanism into Laponitesuspensions. The terminal velocity atdifferent Laponite ages is estimated, asis the microscopic viscosity of theLaponite suspensions (using StokesEinstein law with corrections for walleffects and high Reynolds numbers).

D VijayaraghavanD VijayaraghavanD VijayaraghavanD VijayaraghavanD Vijayaraghavan’s research interests liein the field of nanoparticle-liquid crystalcomposites and their physicalproperties. During the year, he concentrated hisefforts on studying the physical properties of liquidcrystal-nanopar ticle composites, diamagneticproperties of lyotropic liquid crystals and highmagnetic field experiments.

These physical studies were on a ternary lyotropicliquid crystal system. Lyotropic liquid crystallinephases are mostly exhibited by surfactant moleculesdissolved in water under proper temperature-concentration conditions. The basic units of thesesystems are anisotropic micelles. Lyotropic liquidcrystals find diverse applications from ordinary soapsto biophysics and in oil recovery. Their applications

mainly depend on the concentration of theconstituents and temperature. Therefore, it isimperative to understand their phase behaviour andtheir physical proper ties as a function ofconcentration and temperature. To this end,Vijayaraghavan carried out differential scanningcalorimetry (DSC), mass diamagnetic susceptibilityand electrical conductivity of a ternary lyotropicliquid crystal system consisting of sodium decylsulfate (SdS)/decanol/water as a function oftemperature for two different concentrations of the

constituents. It was found that, in theseconcentrations, the system exhibited calamiticnematic (Nc), isotropic (I) and hexagonal (H) liquidcrystalline phases on heating from room temperature.The DSC thermograms exhibited two peaks that canbe related to the reported Nc-I and I-H phasetransition temperatures. However, on cooling froma high temperature, it was found that they did notshow any peak, indicating the absence of liquidcrystalline phases. The temperature dependence ofmagnetic susceptibility and electrical conductivityof both the samples also showed hysteresis.

Magnetic studies showed that the hysteresis was dueto the changes in the sizes of the micelles; however,

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electrical studies showed that the hysteresis was dueto the changes in the viscosity of water. This is anindication that water viscosity is related to the sizesof the micelles. Interestingly, in water-basednanofluids, the sizes of the suspended nanoparticleshave a profound influence on the viscosity of water.

Mass diamagnetic susceptibility studies were alsocarried out on the ternary liquid crystal system fortwo different concentrations of the constituents(41.6/6.6/51.8 wt% – sample 1; 35.47/7/57.5 wt%– sample 2). It was seen that the isotropic phasesusceptibility is temperature dependent at low

temperatures and temperature independent at hightemperatures for both samples; this can be relatedto the low temperature admixtured and hightemperature pure isotropic phases reported for thissample. The susceptibility of sample 1 in the nematicphase is temperature independent while that ofsample 2 is temperature dependent. Diamagneticanisotropy of sample 1 is temperature independentwhile diamagnetic anisotropy of sample 2 istemperature dependent and it is about six timeshigher than that of sample 1 at room temperature.The increase in the shape anisotropy of the micellesin sample 2 due to higher concentration of decanol

and lower concentration of SdS may be responsiblefor this observation. Alcohol and soap moleculesare located mainly in the flat and curved portions ofthese prolate micelles, respectively. Increasing theconcentration of decanol increases the flat portionof the micelles and decreasing the concentration ofSdS decreases the curved portion of the micelles.It is inferred that the resulting change in the micellarshape lead to an increase in the shape anisotropy(length to diameter ratio) of these prolate micelles.This indicates that the diamagnetic anisotropy in thenematic phases of these systems can be fine tuned

by a slight variation in their constituents.A marked change in the susceptibility ofnematic and isotropic phases is observedon dispersing a small amount of singlewalled carbon nanotube in this lyotropicliquid crystal.

There has been considerable interest inbound water, or the water moleculesbound to the micellar head groups orprotein backbones through hydrogenbonding. Such molecules in the hydrationshell around a protein play an importantrole in the protein’s biological activity.Reorientational time correlation functionof water dipoles around the proteinmolecules is calculated using atomistic

molecular simulation and can be used as a tool toevaluate the bound water. For bulk water at roomtemperature (300 K) the water molecules’reorientation time is about 2 pS. When a small protein(1ETN) is added to bulk water, a decrease in thenumber of water molecules reorienting in the 1-2pS range is found. This decrease is inferred to berelated to the presence of bound water in thesystem. An increase in temperature showed a largedecrease in the number of water moleculesreorienting in the 1-2 pS range, thereby indicates

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that the bound water in the system increases withincrease in temperature.

V LakshminarayananV LakshminarayananV LakshminarayananV LakshminarayananV Lakshminarayanan’s research is largely conductedin the Electrochemistry and Surface Science Lab.

During the year, his research included the study ofthe kinetics of adsorption of enzymes on the surfaceof gold electrodes. Studying surface-immobolisedenzyme–substrate interactions is important tounderstand enzyme kinetics and enzyme activity. Itwill also pave the way for the development of novelbiosensors.

In this respect, electrochemical methods have anedge over commonly used optical methods. This isbecause the charges generated during theelectrochemical reactions are reflected in theinterfacial properties of the electrode–electrolytesystem which then can be measured with relativeease. Lakshminarayanan, in collaboration with KSankaran from Anna University and Shrikrishnan (VSP),used electrochemical impedance spectroscopy tostudy the kinetics of enzyme adsorption on thesurface of gold electrodes. They investigatedenzyme adsorption on two types of Self-AssembledMonolayers (SAMs) formed by an amino terminatedthiol and a carboxylic acid terminated thiol. Theadsorption of the enzyme calf intestine alkalinephosphatase was investigated using a newlydeveloped EIS method that was confirmedindependently using Quartz Crystal Microbalance(QCM) and Atomic Force Microscopy (AFM).

Along with Sandeep Kumar and research scholar BSAvinash, Lakshminarayanan covalently functionalizedgraphene oxide sheets with thiol and preparedthiolated graphene oxide self-assembled monolayeron gold surface. Electrochemical studies showedthat the monolayer can partially block the electrontransfer process. The method offers a way ofintegrating thiol chemistry with graphene chemistryto form modified surfaces that possess significantpotential for the device development.

Ferrocene derivatives are interesting molecules forthe study of redox reactions in soft matter as theycan be easily solubilized. They also exhibit excellentredox mediators and can be formed, after suitablethiolation, as self-assembled monolayer films on goldand other noble metal surfaces. The electron transfermediator properties are important from the pointof view of electrochemical enzyme based sensordevelopment. Lakshminarayanan and researchscholars Anu Simon and Swamynathan studied theredox properties of some ferrocence derivatives onferrocence hexane thiol self-assembled monolayersand showed that these properties are dependenton the dielectric properties of the solvent mediumin which the reactions are carried out.

There is an ongoing effort worldwide to develop alow-cost, high-efficiency electrocatalyst for theoxygen evolution reaction as an alternative to thepresently used platinum. As a follow-on of earlierstudies, Lakshminarayanan and VSP student ChayanikaDas are exploring the possibility of using thenanoparticles of nickel and cobalt as oxygenevolution catalysts. They are studying theenhancement in catalytic proper ties of thenanoparticles present on high surface area nickel andcobalt, with encouraging results.

One of the major research effor ts of PramodPramodPramodPramodPramodPullarkatPullarkatPullarkatPullarkatPullarkat’s group is probing the mechanical anddynamical properties of axons. In particular, thegroup is interested in understanding the dynamicsof the axonal cytoskeleton—a biopolymer networkwith force generating capacity—in generating activestresses and in controlling axonal morphology.

In order to probe the mechanical responses of axonsthe group is building a novel custom-made forceapparatus. This set up, built in collaboration withSeshagiri Rao and with help from Chirag Kalelkar, usesan etched optical fiber to apply and measure forcedin the range of a few pico Newton or higher. Using afeedback mechanism, it can be operated in aconstant force (stress) mode or constant elongation

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(strain) mode. This device, which is akin to an AtomicForce Microscope, is built on a powerful microscopewhich allow for high resolution imaging techniquessimultaneous with force measurement. The opticalfiber based force measurement device was usedto perform a couple of preliminary experiments. Fiberfluctuation due to Brownian dynamics was measuredand analysed using liquids of different viscosities(water-glycerene mixtures). The data shows that themean-square fluctuation amplitude that decreaseswith increasing viscosity. A theoretical understandingbased on simple equipartition of energy predictsthat the amplitude should be independent ofviscosity. The inclusion of hydrodynamics or theeffect of a wetting later may explain this discrepancyand these possibilities are being explored along withcolleagues from the Theory Group. Apart from thissurprising result, these experiments show that thesetup is sensitive enough to detect thermalfluctuations in simple liquids at room temperature.

Another set of preliminary experiments was to probeactive suspensions by monitoring the fiberfluctuations caused by bacterial suspensions.Swimming E-coli bacteria produce forces of about1 pico Newton. It was noticed that the observedmean-square fluctuations depended on bacterialactivity. Moreover, the fluctuation amplitudedecreases when bacterial activity is reduced.Statistical analysis reveals significant deviations frompure Brownian dynamics and the nature of thesedeviations depends on the type of motion theparticular strand of bacteria exhibits (tumbling vs.running).

In collaboration with Anagha Datar, Roli Srivatsava andthe group of Aurnab Gosh from IISER, Pune, Pullarkatgroup performed experiments to quantify thebeading process (also known as pearling instability)in axons of tissue-cultured neuronal cells. It was madeclear that axons bead (develop peristaltic shapemodulations) at a typical wavelength whenmicrotubules—one of the biopolymer type in the

cytoskeleton—are made to de-polymerized. Thegroup is trying to understand the mechanism drivingthis beading process. A series of experimentsemploying biochemical techniques was performedto identify the cellular components relevant to thisprocess. Fluorescence microscopy and geneticmethods are also being performed. Preliminary datasuggests that the beading may be driven by theactive dynamics of the axonal cytoskeleton—amechanism different from the recently studiedPearling Instability.

During the year, a new technique to measuremechanical properties and active dynamics of axonswas tested. The idea was to quantify thermal(Brownian) fluctuations of an axon (one micron thickand 100-200 micron long) in order to extract itsspring constant (elastic modulus). This methodlooked promising in our initial comparison betweenlive axons and axons treated with a fixative which“freezes” the internal structure. Experiments withbiochemically treated cells were more difficult toquantify. Pullarkat and his team plan to take thisexperiment fur ther to see if the experimentalmethods can be improved to get over this difficulty.

Another research theme for the year includedpattern formation in differentiating stem cells. Thisresearch aims at investigating stem cell differentiationin externally imposed chemical gradients (such asgrowth factors) and substrate stiffness gradients. Thisis being pursued in collaboration with RenuVishavkarma, Maneesha Inamdar of JNCASR, andJyotsna Dhawan of INSTEM. The aim is to mimic andstudy pattern formation in developing embryos usingstem cells.

VVVVVA Raghunathan A Raghunathan A Raghunathan A Raghunathan A Raghunathan conducts fundamental experimentalresearch in the area of structure and phase behaviourof soft matter systems. He is also involved indeveloping theoretical models of these systems tointerpret the experimental results.

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For the first time, a shear-induced phase transitionwas observed of lamellar (Lα) and isotropic phases(Lx) consisting of bilayers to a crystalline phase (Lc)in a lyotropic surfactant system. In-situ x-ray scatteringmeasurements show that the transition to thecrystalline phase is first order and reversible undershear. An increase in the isotropic to crystallinetransition temperature with shear-rate is revealed inthe shear diagram constructed from rheo-opticalmethods. It has been proposed that the imposedshear field increases the spontaneous curvature ofthe bilayers resulting in the unbindingand consequent redistribution of thehydrophobic counterions. This leads toa coexistence of a lamellar phase ofreduced bilayer separation and acrystalline phase in the counterion-poorand counterion-rich regions of thebilayer, respectively. This study wasdone in collaboration with RemaKrishnaswamy of JNCASR and AK Soodof IISc.

Raghunathan’s research during the yearincluded a phenomenological theory ofphase transitions in two-componentlipid bilayers. Many lipids of biologicalorigin self-assemble in water to formlamellar phases consisting of a periodic stack ofbilayers separated by water. Different lamellar phasesare observed as a function of temperature and watercontent. Raghunathan and PhD students Md. ArifKamal and Antara Pal along with Madan Rao, recentlydeveloped a theory that is able to account for allthe salient structural features of these phases.

This theory has now been extended to two-component lipid bilayers and different generic phasebehaviours of these systems have been calculated.Phase diagrams of these systems have also beenexperimentally determined from x-ray diffractiondata. Phase diagrams obtained from the theory are

found to be in qualitative agreement with theexperimental data.

Coacervates are concentrated colloidal dispersionscoexisting with a dilute aqueous solution. Althoughthey have been widely studied due to theirimpor tance in a variety of applications, theirmicrostructure is sti l l poorly understood.Raghunathan and his team observed the formationof a coacervate when an aqueous solution of theionic surfactant alkenylsuccinic acid (ASA) is dopedwith small amounts of a non-ionic ethoxylated

surfactant. Coacervation resulted from the formationof hydrogen bonds between undissociated COOHgroups of ASA and oxygens in the polyoxyethylenehead groups of the non-ionic surfactant. Similarbehaviour was observed when the non-ionicsurfactant was replaced with polyoxyethylene ofsufficiently high molecular weight. Small-angle x-rayscattering studies show that this phase is made upof bilayers with short-range positional correlations.Cryo scanning electron microscopy images of thisphase show a sponge-like structure. Further studiesare underway to find the structure of this phaseconsistent with the diffraction data and cryo-SEM

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images. This research was in collaboration with PhDstudent Antara Pal, and P Bharat and SG Dastidar ofUnilever Research India.

Raghunathan and Pal studied coacervation of theanionic surfactant sodium dodecylsulphate on theaddition of the organic salt, p-toluidine hydrogenchloride. At equimolar concentration of these twospecies, this system forms a dispersion ofmultilamellar vesicles (MLV) at low temperatures. Onincreasing the temperature, these MLV first transforminto unilamellar vesicles, which on further heatingform a coacervate. The coacervate shows flowbirefringence and its diffraction pattern correspondsto bilayers with short-range positional correlations.Cryo scanning electron microscopy images of thecoacervate show honeycomb-like structures. Furtherwork is underway to elucidate the structure of thecoacervate.

Many toxins, such as cholera toxin and shiga toxin,gain entry into the host cell by first binding and theninducing tubulation in the plasma membrane.Experiments using model membranes show that suchtubulation occurs only with certain class of lipids. Inorder to understand the shape changes inducedby these toxins in membranes, Raghunathan, PhDstudent S Madhukar and J Ludger of the Institute Curiein Paris, France, have studied the binding of thesetoxins to a membrane stack. On binding to themembrane, the toxin molecules are found to formhighly ordered clusters. Further studies are underwayto probe the shape changes of the bilayer inducedby the bound toxin.

Amphiphilic molecules self-assemble in water toform aggregates of various morphologies, such asspheres, cylinders and bilayers. In addition to thesewell-known morphologies, some of these systemsalso form a network of cylinders over narrow regionsof the phase diagram. Raghunathan and PhD studentSantosh Prasad Gupta recently found surfactant-water systems consisting of a cationic surfactant and

an organic additive, where such catenoid phases ofdifferent symmetries occur as a function oftemperature/composition. The influence of thechemical structure of organic additives on theformation of catenoid phases was studied. Smallchanges in the structure of the organic additive arefound to have a significant effect on the phasebehaviour of the mixture.Current research is looking atthe influence of these additiveson the morphology of thesurfactant micelles, in order tounderstand the formation andstabil ity of the catenoidphases.

Post Doctoral Fellow GGGGGKavithaKavithaKavithaKavithaKavitha’s work during the yearincluded preliminary studies todevelop the necessaryinstrumentation in a shor ttimeframe and start studyingthe columnar liquid crystalsystems. These were incollaboration withV. Lakshminarayanan, Arun Royand Sandeep Kumar.

Developing organicphotoconductors with suitablyhigh charge carrier mobility isan interesting challenge. Toachieve a fast and effectivetransport of charges throughorganic medium it is requiredthat the charge carrier units arepositioned such that sufficientmutual orbital overlap of the units is guaranteed. It isclear that only highly ordered system such as liquidcrystals will fulfil this condition. For this, Kavithafocused on designing an instrument to measure thephotoconductivity of liquid crystals. She and her

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collaborators successfully set up the directphotocurrent measurement with the function oftemperature and started getting results from dopedand undoped triphenylene derivatives.The photoconductivity measurement of doped andpure triphenylene derivatives was carried out for thefirst time.

It was found that after dopingHAuCl4, some triphenylenederivatives showedconductivity enhancementby several orders. Someof the photoconductingtriphenylene derivativesshowed signif icantenhancement due to theillumination of light. Theseresults have been sent to theElsevier journal.

During the year, Kavitha alsoconducted a study of carbonnanotube stabil ised bluephase (BP) liquid crystals. TheBP is believed to be based ona locally doubly-twistingstructure in which the helix axislies in all 360o directions.Depending on how thedouble-twist structure orientthemselves in threedimensional space, BPs arefurther categorized into BPs I,II and III, which are body-centred cubic, simple cubicsymmetry, and amorphous,

respectively. BPs are attracting both scientific andtechnological interest with regard to the prospectof creating next generation optical devices utilisingtheir fascinating optical characteristics such asiridescence and macroscopic optical isotropy.

However, their complex structure also limits theirtemperature range to only a few Kelvin below theclearing point of the material, and as a result, recentresearch has focused on developing techniques toexpand the temperature range of the BPs. In orderto get the BP, Kavitha and her collaborators used a50% mixture of E7 (multicomponent nematicmixture) CN (cholesteryl nonanoate). A single wallcarbon nanotube was used to stabilize the BP, whichwas obtained at around 8ºC. Suppor tingexperiments being conducted include DSC, TEM andelectrooptic studies.

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THEORETIPHYSICS

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CALICALoverviewEstablished in 1995, the Theoretical Physics (TP) group comprisesresearch faculty, post doctoral fellows and students who work atthe interface between mathematics and physics. There are twomain areas of research – gravity and statistical mechanics. Areas ofinterest within statistical mechanics are mesoscopic physics, non-equilibrium physics, soft condensed matter physics and biophysics.Research in general relativity includes gravitational waves andquantum gravity.

Members often engage in collaborations among each other and/or groups of the institute that conduct experimental physicsactivities. The group has also created a forum for theorists toconduct simple table-top experiments that can express conceptualpoints.

The following pages summarize the major areas of research for theTP group. Each member’s individual work during the last year isprovided in the next section, giving the reader a more detailedand technical description of their respective research activities.

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STATISTICAL MECHANICSWhen a macroscopic device or a sample of bulkmaterial is scaled down to mesoscopic size (from afew microns to the size of a single atom), they beginto reveal quantum mechanical effects. As a result, itsproperties might be very different from its parentmaterial.

Research at RRI is focused on the development of atheory of heat and electron transport in suchmesoscopic scale systems. Part of that work includesanalytical and numerical treatment of Fourier’s lawof heat conduction in disordered harmonic andanharmonic crystals. Theoretical and experimentalresearch in that f ield is impor tant for theadvancement of our fundamental understanding ofthe transport properties of materials, which in turnwould lay the foundation needed to improve theperformance of nanodevice applications andtechnologies.

The development of fast algorithms to estimate theprobability of rare events is part of the ongoingresearch in the field of non-equilibrium statisticalmechanics. Developed in the context of physics,such algorithms are also important in other areas oflife like finance and cellular processes in biology.

BIOLOGICAL PHYSICSVarious topics in the field of biophysics haveattracted the interest of the TP group, includingmitochondrial distribution dynamics, vesicleformation and the development of analytical modelsto describe DNA elasticity (stretching, twisting andvarious deformations). Membranes and transport ofmaterials in the cell are other topics that have beenpursued at RRI. Research in biophysics involves activecollaboration with experimental groups on campusand at the National Centre for Biological Sciences(NCBS) of TIFR.

GRAVITATIONAL WAVESThe existence of gravitational waves was predictedby Albert Einstein’s theory of general relativity in1916. Their existence is inferred using indirectmethods but they have not been measured directlyyet. The direct detection of such waves will not onlyhelp scientists test general relativity more thoroughlybut, more importantly, it will open up objects andphenomena in the universe that have thus far beeninvisible to opticaland radioastronomy.

In general, sourcesof gravitationalwaves are bodieswith a strongtime dependentgravitational field.These sourcesinclude binarystar systemscomposed ofwhite dwar fs,neutron stars orblack holes. Theorbiting bodiesof such systemsc o n t i n u a l l ylose energywhile radiatinggravitational waves. This leads to a decrease in thedistance between the bodies, forcing them to rotatemore rapidly and thus increasing their loss of energyto gravitational radiation. For systems like the Sun-Earth, one may calculate this effect and will find it tobe negligible on the time scales of the universe. Thecloser the bodies in the binary system, the largerthis effect is, leading eventually to a collision thatcan result in a merger or the creation of a black hole.

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Such binaries are referred to as inspiralling binariesbecause the bodies in the binary system describe aspiral as they approach each other.

Laser Interferometer Gravitational-wave Observatory,or LIGO, is a joint scientific experimental projectattempting to detect directly gravitational waves. Theproject is led by scientists and engineers from MIT,Caltech and other universities. VIRGO is anotherinterferometer aimed at direct gravitational wave

detection, and is theresult of the effor t ofvarious Europeaninstitutions. Both theseinstruments have beenbuilt and tested and haveachieved their designsensitivities. The signalsexpected are extremelyweak and buried innoise. A major challengenow is the accuratecalculation of theexpected gravitationalwaveforms from theobserved binarysystems. Thesewaveforms will then becross-correlated with theobservational data toextract the gravitationalwave signature.

Researchers at RRI are currently looking at ways toprecisely calculate the gravitational waveform fromfew inspiralling binaries. In the future, this research isexpected to help improve the sensitivity of otherenvisioned space instruments aimed at detectinggravitational waves like LISA (Laser InterferometerSpace Antenna).

QUANTUM GRAVITYThe formulation of a theory of quantum gravity hascurrently engaged the minds and creativity of a majorpart of the theoretical physics community. Quantumgravity (QG) is envisioned to be a self consistenttheory that will quantize the gravity field, thuscombining the two major theories of quantummechanics and general relativity. There are a handfulof QG theories being developed in parallel, like thestring theory, loop quantum gravity and causal settheory. Research at RRI has focused on the last twoapproaches to quantum gravity.

Loop Quantum theory proposes that all the spacewhere physical phenomena happen can berepresented by the continuity of finite quantizedloops of excited gravitational fields called spinnetworks. Unlike string theory, loop quantum gravity(LQG) doesn’t try to unify all four major forces(electromagnetic, gravitational, strong nuclear andweak nuclear). The major challenge for LQG comesfrom the fact that quantum theory relies on areference (background) space-time, while generalrelativity is said to be background independent. Theapproach of LQG is to formulate quantum mechanicswithout relying on the space-time reference.Members of the Theoretical Physics group at RRIdevelop new mathematical tools and ideas to getcloser to the development of a true theory ofquantum gravity.

Causal Set theory is another approach to quantumgravity. Its founding principle states that space-timeis fundamentally discrete and the relations betweenspace-time events are causal. Members at RRIfocusing on causal set theory investigate classicalstochastic growth modes, topology and dynamicsof the causal set in their attempt to construct aconsistent quantum theory of causal sets. Parallel tothat, investigations of the observer-independentalternative formulation of quantum theory arecurrently being conducted.

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In his early days, Einstein believed that the universewas static. His general relativity theory was predictingotherwise, so he added a term called thecosmological constant that made the universe static.

Later on, Hubble provided observational proof thatthe universe was expanding and Einstein abandonedthe cosmological constant calling it the “biggestblunder” in his career. Recently, the interest in thecosmological constant among cosmologists and

theoretical physicists has increased mainly becauseits inclusion as a cosmological parameter significantlyimproves the agreement between theory andobservation.

The gravitational pull of matter is expected to slowdown the expansion of the universe. Surprisingly,observations of supernovae indicate that theexpansion of the universe is accelerating! Suchresults, though preliminary in nature, raise thepossibility that the universe contains an unknownform of matter or energy that is gravitationallyrepulsive. The cosmological constant may describesuch matter or energy, but a lot more work remainsbefore cosmologists and theoretical physicists canthrow light on this. Another reason for thereintroduction of the cosmological constant is thatthe estimated age of the universe (with the amountof matter we observe) by cosmological models thatdon’t take it into account is less than the age of theoldest stars we observe. When the cosmologicalconstant term is added to the standard theory ofBig Bang it becomes consistent with variousastronomical observations. Building on the work ofSorkin, who suggested that the observedcosmological constant may be due to quantumgravity fluctuations, researchers at RRI pursue ananalogy between that elusive term in the theory ofgeneral relativity and the surface tension of fluidmembranes. This is yet another example of thecollaborations that emerge at the institute due tothe interactions between members with differentfields of research.

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ongoingresearch

Sanjib SabhapanditSanjib SabhapanditSanjib SabhapanditSanjib SabhapanditSanjib Sabhapandit’s research spans various topics of statisticalphysics, including statistical physics of out-of-equilibrium systems,disordered systems, stochastic processes, extreme value statistics,integer partitions, granular media, dynamics of polymers, and largedeviations of rare events for various non-equilibrium additiveprocesses.

During the last year, Sabhapandit studied the statistics of recordsfor a time series generated by a continuous time random walk,and found them to be independent of the details of the jumplength distribution, as long as the latter is continuous and symmetric.However, the statistics depend crucially on the nature of thewaiting-time distribution. The probability of finding M records withina given time duration has a scaling form, and the exact scalingfunction is obtained in terms of the one-sided Lévy stabledistribution. The mean of the ages of the records, defined as <t/M>, differs from t/<M>. The asymptotic behaviour of the shortestand the longest ages of the records were also studied.

He also studied large deviations of heat flow in harmonic chainsalong with his colleagues Anupam Kundu and Abhishek Dhar. Theheat transport across a harmonic chain connected at its two endsto white-noise Langevin reservoirs at different temperatures wasconsidered. In the steady state of this system, the heat Q flowing

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from one reservoir into the system in a finite time thas a distribution P(Q,t). Sabhapandit studied thelarge time form of the corresponding momentgenerating function <exp[-s Q]> ~ g(s) exp[t m(s)]and obtained exact formal expressions, in terms ofphonon Green’s functions, for both m(s) and thelowest order correction g(s). In general, a knowledgeof both m(s) and g(s) is needed to find the largedeviation function associated with P(Q,t). Thefunction m(s) is known to be the largest eigenvalueof an appropriate Fokker-Planck type operator andthis method also gives the cor respondingeigenvector exactly.

Work on finding the probabilities of rare events innonequilibrium processes, in collaboration withAbhishek Dhar and Anupam Kundu, was alsocontinued during the year.

Abhishek DharAbhishek DharAbhishek DharAbhishek DharAbhishek Dhar’s research interests span several areasin theoretical physics and he has worked in tandemwith researchers from CEA in Grenoble, France, TokyoUniversity, University of California Santa Cruz, TIFR andRRI.

During the year, Dhar and his collaborators haveextended the use of the Green-Kubo formula tostudy frequency-dependent thermal conductance.These results are expected to be useful inunderstanding nonequilibrium measurements ofthermal conductivity in experiments on lowdimensional systems.

Dhar and Keiji Saito from Tokyo University providedthe first numerical verification of Fourier’s law. Fourier’slaw of heat conduction is a phenomenological lawand it does not have a rigorous microscopicderivation. The law is not known to be valid in low-dimensional systems in general, and there has beenthe question of what the necessary conditions arefor Fourier’s law to be valid in three-dimensionalsystems. In dielectric crystals, lattice vibrations (orphonons) are the carriers of heat and an importantmechanism for scattering is via phonon-phonon

interactions. To investigate whether this gives finiteheat conductivity, Dhar and Saito performed non-equilibrium simulations of heat conduction in a threedimensional anharmonic lattice. It was found fromnumerical data that the three dimensional system hasa finite thermal conductivity. The cross-over fromone-dimensional to three dimensional behaviour ofthermal conductivity was also examined.

In stochastic processes, there are events that occurwith extremely rare probabilities. However, whenthey do occur, they can have severe consequences,and so it is important to be able to predict theprecise probabilities of these rare events. A simpleexample would be the mutation of a gene undernormal conditions. In the context of transport, Dhar,Sabhapandit of RRI and Kundu of CEA, France, havedeveloped an algorithm to accurately and efficientlycompute the probabilities of rare events such as theflow of current against a potential gradient.

The large deviation function (LDF) is an importantquantity that carries information on fluctuations innonequilibrium processes. In the context oftransport, the LDF contains information on the steadystate current and all moments of current-fluctuationsin a system. A special symmetry property of the LDFis referred to as the fluctuation theorem, and seemsto be satisfied in a large class of nonequilibriumprocesses. There are few examples of many-particlesystems where the LDF has been analyticallycomputed. Recent research of Dhar and hiscollaborators – Anupam Kundu, Keiji Saito and SanjibSabhapandit – included obtaining analyticexpressions for the LDF for heat transport in arbitraryharmonic networks. They were also able to find thecorrection to the LDF for a one-dimensional harmonicchain, which is needed to establish the validity ofthe fluctuation theorem in this system.

The measurement of heat transpor t in low-dimensional systems such as nanowires, nanotubesand grapheme has garnered quite a bit of interest in

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recent times. This is due to the fact that propertiesof low-dimensional systems can be completelydifferent from those of the bulk three-dimensionalsample. Understanding transport properties isimportant with regard to technological applicationssuch as developing nanodevices.

Some interesting data was recently obtained by agroup in TIFR on thermal conductivity in n-typedoped In-As nanowires. The most interesting resultwas that the thermal conductivity was about 1,000times smaller than bulk samples while the electricalconductivity was almost unaffected. Secondly, it was

found that applied gate voltages had a strong effecton the thermal conductivity. Dhar and hiscollaborators from TIFR obtained some qualitativeunderstanding of these results.

SupurSupurSupurSupurSupurna Sinhana Sinhana Sinhana Sinhana Sinha’s areas of interest include statisticalmechanics of semiflexible polymers, geometricphase and optics.

Her work during the year included research into topsand writhing DNA, done in collaboration with JosephSamuel. The torsional elasticity of semiflexiblepolymers like DNA is of biological significance. Fullerbegan a mathematical treatment of this problem usingthe relation between link, twist and writhe, but was

hindered by the non-local nature of the writhe. As aresult, an analytic statistical mechanical treatment thattakes into account thermal fluctuations in computingthe partition function has not been possible. In thisstudy, the well known analogy with the dynamics oftops has been used to show that when subjectedto stretch and twist, the polymer configurations thatdominate the partition function admit a local writheformulation in the spirit of Fuller and thus provide anunderlying justification for the use of Fuller’s “localwrithe expression”. This has led to considerablemathematical simplification in solving theoreticalmodels of DNA and elucidating their predictions.The results facilitate comparison of the theoreticalmodels with single molecule micromanipulationexperiments and computer simulations.

Experiments have been conducted on biopolymerslike double stranded DNA, which twist and stretchsingle molecules to probe their elastic properties.Thermal fluctuations play an important role indetermining molecular elastic properties, but a fulltheoretical treatment of the problem of twist elasticityof fluctuating ribbons using the simplest worm likechain model (WLC) remains elusive. Sinha’s study ofthis problem involved first taking a mechanicalapproach and then incorporating thermal effects ina quadratic approximation applying the Gelfand-Yaglom (GY) method for computing fluctuationdeterminants. The study interpolates betweenmechanics and statistical mechanics in a controlledway and shows how profoundly thermal fluctuationsaffect the elasticity of semiflexible polymers.

The new results include:

• A detailed study of the minimum energyconfigurations with explicit expressions for theirenergy and writhe and plots of the extensionversus link for these configurations

• A study of fluctuations around the local minimaof energy and approximate analytical formulae

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for the free energy of stretched twisted polymersderived by the GY method

Insights derived from the mechanical approach havebeen used to suggest calculational schemes that leadto an improved treatment of thermal fluctuations.From the derived formulae, predictions of the WLCmodel for molecular elasticity can be worked outfor comparison against numerical simulations andexperiments.

During the year, Sinha, Joseph Samuel and PoonamMehta continued their research into the non-localPancharatnam phase in two-photon interferometry.They proposed a polarised intensity interferometryexperiment that measures the non-localPancharatnam phase acquired by a pair of HanburyBrown-Twiss photons. The setup involves twopolarised thermal sources illuminating two polariseddetectors. Varying the relative polarisation angle ofthe detectors introduces a two photon geometricphase. Local measurements at either detector donot reveal the effects of the phase, which is an opticalanalogue of the multiparticle Aharonov-Bohm effect.The geometric phase sheds light on the three slitexperiment and suggests ways of tuningentanglement.

She also studied atom interferometers and thegravitational redshift, along with Samuel. From theprinciple of equivalence, Einstein predicted thatclocks slow down in a gravitational field. Since thegeneral theory of relativity is based on the principleof equivalence, it is essential to test this predictionaccurately. Muller, Peters and Chu claim that areinterpretation of decade-old experiments withatom interferometers leads to a sensitive test of thisgravitational redshif t effect at the Comptonfrequency. Wolf et al dispute this claim and adducearguments against it. In this study, these argumentsare distilled to a single fundamental objection: anatom is not a clock ticking at the Compton frequency.It is concluded that atom interferometry experiments

conducted to date do not yield such sensitive testsof the gravitational redshift. The study suggests a newinterferometric method to probe gravitationalredshift.

Joseph Samuel Joseph Samuel Joseph Samuel Joseph Samuel Joseph Samuel is a mathematical physicist whoworks in the fields of general relativity, optics andsoft condensed matter physics. He uses geometryand topology to describe physical phenomena.

One of his interests is the elasticity and statisticalmechanics of DNA. His research during the past yearincluded understanding DNA elasticity using thestandard techniques of statistical mechanics. Whileexperiments do exist, their interpretation requiresspecial attention due to the geometric andtopological subtleties of the Writhe. This work, incollaboration with Supurna Sinha, examines theeffect of thermal fluctuations on the statisticalmechanics of DNA by using the Gelfand-Yaglommethod for computing fluctuation determinants.

Under the field of gravitation, Samuel worked onatom interferometers and the gravitational redshift,in collaboration with Sinha. The aim of this study wasto determine whether atom interferometry can beused to accurately test the redshift effect by criticallyexamining the idea of a clock in general relativity.The study leads to a proposal of a new class ofexperiments in gravitation which study theinterference of quantum clocks.

Bala IyerBala IyerBala IyerBala IyerBala Iyer’s principal research interests are in the fieldof general relativity. He has been studying thecomputation of high accuracy gravitationalwaveforms for ICB using multipolar post-Minkowskianmethods. These high accuracy post-Newtonian (PN)waveforms have resulted in the construction of GWtemplates for GW data analysis. They are also vital tovalidate recent numerical waveforms of plungemerger and ringdown and assess their accuracy andinterpretation.

Inspiralling compact binaries (ICB) of neutron starsand black holes are the most promising sources of

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gravitational waves (GWs) for terrestrial laserinterferometer GW detectors like LIGO and VIRGOand space detectors like LISA. GW signals are veryweak and buried in the detector noise and can onlybe extracted and characterized using techniqueslike matched filtering.

During the year, Iyer, in collaboration with CK Mishraand KG Arun from the Chennai Mathematical Institute,studied the 2.5PN linear momentum flux and recoilfrom ICBs in circular orbits.

Anisotropic emission of GWs from ICBs results in aloss of linear momentum and hence gravitationalrecoil of the binary system. The loss rate of linearmomentum in the far zone of a nonspinning binarysystem of black holes in a quasi-circular orbit wasinvestigated at a 2.5PN order. This was used toprovide an analytical expression in harmoniccoordinates for the 2.5PN accurate recoil velocityof the binary system in the inspiral phase of itsevolution.

The 2.5PN computations are more involved due tothe presence of hereditary terms in addition to themore familiar instantaneous terms. The maximumrecoil velocity of the binary system at the end of itsinspiral phase is of the order of 4 km/s and smallerthan the 2PN estimate. Iyer and his collaborators alsoprovided an estimate of the maximum recoil velocityat the end of the plunge (involving contributions bothfrom the inspiral and plunge phases) for a binarywith symmetric mass ratio 0.2 is of the order of 183km/s.

Madhavan VMadhavan VMadhavan VMadhavan VMadhavan Varadarajanaradarajanaradarajanaradarajanaradarajan’s research interests are in thefield of classical and quantum gravity.

He continued his research into the issue ofinformation loss in two-dimensional black holes, incollaboration with A Ashtekar from Penn StateUniversity and V Taveras from Louisiana StateUniversity. The research is in its final stages and anew outcome during the last year was the

construction of a mechanism for informationrecovery in the four-dimensional collapse situation.This used the idea of “rapid” singularity resolutionand seemed to evade the standard argumentsagainst such recovery.

Varadarajan has also continued his work towards theconstruction of an anomaly-free quantum dynamicsfor Loop Quantum Gravity (LQG).

The recent formulation of the Parameterized FieldTheory (a covariant reformulation of two-dimensionalflat spacetime free scalar field theory) using an LQG

type ‘polymer’ model formed its basis. Physical stateswere constructed, without intermediateregularization structures, by averaging over the groupof gauge transformations generated by theconstraints (the constraint algebra was a Lie algebra).Varadarajan and post-doctoral fellow Alok Laddhaconsidered classically equivalent combinations ofthese constraints cor responding to adiffeomorphism and a Hamiltonian constraint, which,as in gravity, define a Dirac algebra.

The findings included the fact that the (triangulated)Hamiltonian constraint acts only on vertices, itsconstruction involves some of the same ambiguities

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as in LQG and its action on diffeomorphism invariantstates admits a continuum limit.

Varadarajan and Laddha also constructed thesmeared diffeomorphism constraint operator at finitetriangulation from the basic holonomy-flux operatorsof LQG, evaluate its continuum limit on theLewandowski-Marolf habitat and show that theaction of the continuum operator provides ananomaly free representation of the Lie algebra ofdiffeomorphisms of the 3-manifold.

The results of this analysis indicate a conceptualsimilarity between LQG and the so-called “mu-bar”scheme of Loop Quantum Cosmology.

During the year, Sumati SurSumati SurSumati SurSumati SurSumati Surya ya ya ya ya studied Markov ChainMonte Carlo (MCMC) methods for Causal Setquantum gravity in collaboration with Joe Hensonof Imperial College, London, David Rideout ofUniversity of California San Jose and Rafael Sorkin ofPerimeter Institute.

MCMC methods have proven to be very importantin probing the structure of quantum gravity, asuccessful example of this being the Causal DynamicalTriangulation (CDT) approach to quantum gravity. Inthat approach, extensive numerical work has beencarried out and there is a strong suggestion that thetheory generates a universe much like ours with apositive cosmological constant. The MCMC methodscan also be used in the Causal Set approach toquantum gravity, which begins from a very differentset of first principles. Using these techniques, Suryaand her collaborators looked into whether CausalSet Theory (CST) belongs to a different universalityclass than the CDT approach, or whether the physicsat intermediate scales, which they both describe, isthe same.

A suite of numerical algorithms for using MCMC forcausal sets was constructed using the Cactusframework for the general case. Results confirm thepredicted dominance of entropic configurations inthe infinite temperature limit. For finite temperatures,

analytic arguments show that entropic dominanceis suppressed by the causal set action in four-dimensions. However, it was shown that thesimulations take too long to thermalise, and theMarkov chain remains in the high entropyconfigurations. The main reason is that the highentropy configurations have a specific ordertheoretic structure, which does not change underthe class of moves considered. Attempts are on toconsider a more suitable class of moves which couldhelp achieve thermalisation.

The analysis of the 2-dimensional models of causalset quantum gravity using MCMC methods wasinitiated and a suite of numerical algorithmsconstructed using the Cactus framework. It wasshown that this simplified model of causal setquantum gravity overcomes many of the hurdlespresent in the general case. In particular, it was shownto be computationally erdogic and to thereforethermalise rapidly. Several tests were carried out toestablish the stability of the code and the ergodicityof the Markov process. Recent progress indicatesthe existence of a new layered quantum gravityphase, and investigations are continuing to confirmthis.

In early universe models of cosmology, like inflation,a strong assumption is made about the nature ofinteractions even at scales much smaller than the GUTscale. However, “mesoscale” effects from quantumgravity can have a strong influence on the nature ofthese interactions even at non-Plankian energies. Anexample of this is non-locality which arises fromcausal set theory. Work has been initiated inunderstanding the role of a causal set induced non-locality in early universe cosmology in conjunctionwith Robert Brandenberger of McGill University andRafael Sorkin.

It is vital to quantum gravity to be able to constructcovariant observables in a measurementindependent framework. In the causal set approach,such observables can be constructed using the

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quantum measure, and Surya’s recently developedformalism makes it possible to answer concretequestions. It was shown that not all admissibledynamics allow the construction of a formallycomplete set of observables. However, it was seenthat a weaker criterion may be applied which givesa physically meaningful class of observables (asopposed to a formally complete set). Efforts are onto understand whether this weaker criterion also limitsthe class of dynamics in collaboration with RafaelSorkin and Fay Dowker and Steven Johnston ofImperial College.

PPPPPoonam Mehta oonam Mehta oonam Mehta oonam Mehta oonam Mehta is a Post Doctoral Fellow whoseresearch interests touch upon the various theoreticaland phenomenological aspects related to neutrinos– one of the most elemental and hard-to-detectelemental par ticles. She is also interested ingeometric phases in neutrino oscillations. Asneutrinos exhibit sustained quantum coherence overastrophysical length scales, researchers are interestedin the properties of these particles in these coherentphases.

During the year, Mehta and Walter Winter ofWuerzburg University, Germany, looked into theimportance of flavor ratio measurements in neutrino

telescopes. The detected flavor ratios carry theenergy information of specific new physics scenariosthat alter the transition probabilities in distinctiveways, as well as the energy dependent flavorcomposition at the source. Mehta and Winter studiedthe interplay of these two energy-dependent effectsand identified which new physics scenarios can bedistinguished from the detected flavor ratios as afunction of astrophysical parameters. The study wasdone using a self-consistent neutrino productionmodel.

Other areas of Mehta’s research during the yearinclude the issue of obtaining large mixing inthe neutrino sector as revealed by low energydata in left-right symmetric models and thecharacterisation of geometric phases in three-flavor neutrino oscillations.

RRRRRyuichi Fyuichi Fyuichi Fyuichi Fyuichi Fujita ujita ujita ujita ujita is a Post Doctoral Fellow whoseresearch interests include the study ofgravitational waves and general relativity. Heworked on the derivation of the gravitationalwaveforms needed to compute the 14thpost-Newtonian (14PN) order energy flux ina circular orbit around a Schwarzschild blackhole. The 14PN expressions will lead to theparameter estimation comparable tonumerical waveforms for extreme mass ratioinspirals, which are one of the main targets of

Laser Interferometer Space Antenna (LISA).

Fujita also derived the fitting formulae of the rates ofchange of constants of motion and the associatedrates of change of orbital elements due togravitational radiation by a test particle in eccentricinclined orbits around a Kerr black hole.

Such formulae are useful to construct a templatebank of gravitational waves from extreme mass ratioinspirals and develop an algorithm for LISA dataanalysis since the computation of numericalwaveforms is very expensive and may be bypassedby the formulae.

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RRRRRoman Sverdlov oman Sverdlov oman Sverdlov oman Sverdlov oman Sverdlov is a Post Doctoral Fellow whoseresearch interests include quantum gravity and causalset theory.

One of his major topics of research during the yearwas including particle creation and annihilation intodeterministic Pilot Wave model. Generalizing the PilotWave model to second quantization is difficult, unlikethe well-know first quantization, since creation andannihilation of particles is a “discrete” process andis not easy to view deterministically. Sverdlovproposed the introduction of extra compactifiedcoordinate to overcome this difficulty.

Whenever the par ticle is on one side of the“semicircle”, it is visible. When it is on the “other side”,it is invisible. Thus, its trajectory in that extracoordinate is differentiable (and, therefore, can bedeterministic). However, when the particle “crosses”the “line” between two semicircles, its visibilityundergoes a “discrete jump”. The timing of that jumpcan be predicted and, therefore, determinism ispreserved. But this, unfortunately, requires theallowance of gross non-locality, which is far “worse”than non-localities present in other Pilot Wave modelsand results in a trade-off between having to faceunwanted non-locality and preserving desireddeterminism.

Sverdlov also encoded the mathematical informationabout configuration or Fock spaces within ordinary,three dimensional space. This was done bydiscretizing the former, while leaving the latter in acontinuum form, thus making sure that it has “lessinformation” than the latter. He is also studying thecombination of the Bohmian and Ghirardi-Rimini-Weber (GRW) approaches in such a way that each“cures” some of the shortcomings of the other. Hisapproach involves taking the collapse mechanismproposed by GRW and modifying it in such a waythat it is centered around the Bohmian particle.

Post Doctoral Fellow SamarSamarSamarSamarSamarth Chandrath Chandrath Chandrath Chandrath Chandra’s professionalresearch interests include spin glasses andbiophysics.

In collaboration with Barry Richmond of NationalInstitutes of Health in the US, Chandra exploredmodels for the effect of the absolute refractoryperiod of a neuron on the statistics of its spike train.They were able to construct simple models, two ofwhich they were able to solve analytically whileanother model was mapped to a well-studiedproblem in queueing theory. They also explored thequestion of what should be the dynamical rules forthe processing of spikes by a neuron so that anincoming Poisson spike train leads to a Poisson spiketrain as output.

Chandra’s other research theme included exploringthe behaviour of spin glasses as a function of spinspace dimension. He found that the behaviour ofspin glasses changes significantly at specific spinspace dimensions. Connection of this result toprotein folding and structural glasses has beenexplored.

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facilities

LaboratoriesRadio Astronomy Lab (RAL)The Radio Astronomy Lab (RAL) at RRI consists of three divisions– Digital Signal Processing (DSP) Lab, Millimeter Wave and RFLab, and X-Ray Astronomy Lab.

DSP LabDSP LabDSP LabDSP LabDSP Lab

The DSP lab is involved in the design, development and testingof digital receivers for astronomy. The DSP lab team comprisesskilled engineers with expertise in the field of digital circuitdesign and digital signal processing. RRI has a long history ofdesign and development of a variety of digital systems(receivers, spectrometers, correlators) that have improved thecapabilities of national and international telescope facilities.The lab has modern CAD design packages for the developmentof FPGA-based digital systems.

Millimeter WMillimeter WMillimeter WMillimeter WMillimeter Wave and RF Labave and RF Labave and RF Labave and RF Labave and RF Lab

The engineers from the RF lab are experienced professionalswith diverse skill-sets in the design and development ofmillimeter wave and RF systems. The lab is equipped with allnecessary fabrication and testing facilities for RF systemscharacterisation. The group has designed and built feeds,broadband antennas as well as standard and special purposefront end receiver systems operating at wavelengths fromdecameter to millimeter.

XXXXX-Ray Astronomy Lab-Ray Astronomy Lab-Ray Astronomy Lab-Ray Astronomy Lab-Ray Astronomy Lab

The X-ray lab is a fully equipped laboratory for developmentand testing of X-ray astronomical instrumentation. Theinfrastructure includes a clean room, X-ray generator, beamline, polarizer and monochromator, vacuum systems, mountsand electronics for performance evaluation of X-ray detectors.

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LAMP Group LabsEach faculty member of the LAMP group at RRI runslab facil it ies specific to his/her individualresearch.These four labs are:

• The Laser Cooling, Light Scattering Lab

• The Ultrafast and Nonlinear Optics Lab

• The Quantum Optics Lab

• The Quantum Interactions (QUAINT) Lab

The well-established facilities for laser cooling andtrapping of atoms include vacuum systems,commercial and custom-made lasers, spectroscopyequipment, standard electronics and real timeoperating systems. The lab that hosts an experimentalsystem to investigate quantum walks of light consistsof three Michelson optical interferometers, variousoptical components and acoustic-optical modulator.Two labs allow for experimental research of nonlinearoptical proper ties of nanocomposites anddynamics, and spectral behaviour of laser inducedplasmas. Standard and custom-made facilities in thelab include a femtosecond laser system withamplifier, nanosecond Nd:YAG laser, spectrometers,monochromators, laser beam profiler, ultra highvacuum chamber, X-ray and Gamma-Ray detectors,experimental set up for z-scan and pump probemeasurements, and more.

SCM Group LabsChemistrChemistrChemistrChemistrChemistry Laby Laby Laby Laby Lab

The lab has state of the art facilities necessary forthe synthesis and structure characterisation of novelliquid crystal materials. Major equipment in the labincludes polarizing optical microscopes, highperformance liquid chromatograph, differentialscanning calorimeter, elemental analyser, infrared andUV-Visible spectrophotometer. Over 700mesomorphic molecules have been synthesised andcharacterised in the Organic Chemistry Lab at RRI.

Physical Measurements LabPhysical Measurements LabPhysical Measurements LabPhysical Measurements LabPhysical Measurements Lab

The Physical Measurements Lab is equipped withstandard facilities for phase transition studies in liquidcrystals, liquid crystal nanocomposites and variousmicellar solutions. The lab members are activelyinvolved in the development of new precisetechniques for a variety of phase transitionmeasurements. Available equipment include apolarising optical microscope, dielectric impedanceanalyzer and confocal microscope. Currently, thereare experimental set ups for conoscopic, switchingcurrent and various electro-optical measurements.

Liquid CrLiquid CrLiquid CrLiquid CrLiquid Crystal Display Labystal Display Labystal Display Labystal Display Labystal Display Lab

The LCD lab has basic facilities for fabrication of liquidcrystal cells and small size (100mmX100mm) displaysas well as standard electronics equipment for theirtesting. Spin coating system, vacuum deposition unit,rubbing machine and temperature controlled ovensare frequently used by the lab members.

Rheology and Light Scattering LabRheology and Light Scattering LabRheology and Light Scattering LabRheology and Light Scattering LabRheology and Light Scattering Lab

The lab utilizes rheology and light scatteringtechniques to study the dynamics of soft glassymaterials and amphiphilic systems. The mostfrequently used instrumentation in the lab includesa dynamic light scatterometer and a rheometer.Rheology, dynamic light scatterometry and diffusingwave spectroscopy are some of the measurementtechniques used in the lab.

XXXXX-Ray Diffraction Lab-Ray Diffraction Lab-Ray Diffraction Lab-Ray Diffraction Lab-Ray Diffraction Lab

The X-ray lab is set up for investigating the phasebehaviour of various sur factants using X-raydiffraction. Polarizing l ightmicroscopy and small angle X-ray scattering techniques areof ten used in the lab. Toper form precise X-raymeasurements, the lab isequipped with a confocalmicroscope, X-ray

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diffractometer and a small angle X-ray scatterometer.

Biophysics LabBiophysics LabBiophysics LabBiophysics LabBiophysics Lab

The Biophysics lab is a self-sufficient lab where variouscells can be grown, manipulated and analyzed. It isequipped with two fully motorised microscopesallowing for fluorescence and face contrastmicroscopy measurements, confocal microscope,biosafety cabinet for growing cells, incubators,centrifuge and a 3D microscope for dissections.

ElectrochemistrElectrochemistrElectrochemistrElectrochemistrElectrochemistry and Sury and Sury and Sury and Sury and Surface Science Labface Science Labface Science Labface Science Labface Science Lab

The lab performs controlled experiments on testsur faces in electrochemical cells usingelectrochemical instruments such as a potestiostat,frequency response analyzer and lock-in amplifier.An electrochemical quartz crystal microbalance isused to measure mass changes. Thin f i lmcharacterisation is done with a variety of scanningprobe techniques l ike scanning tunnell ingmicroscopy, atomic force microscopy and others.

Mechanical EngineeringThe mechanical workshop at RRI meets themechanical design and fabrication needs of RRIexperimental activities. It has the necessary machineryand a team of skilled personnel who can undertakefabrication of various sophisticated mechanicalhardware components for electronicsinstrumentation as well as sheet metal work forcomponent, receiver enclosures, and system racks.The expertise of the mechanical workshop team hasbeen used in large projects like the fabrication and

installation of 1100 helicalantennas for the Mauritius Radiotelescope, design andfabrication of a low frequencyantenna feed system for GMRT,and fabrication of a multi-bandfeed for the Green Bank

telescope, West Virginia. Specific tasks such asfabrication of precision mounts, positioners andcooling stages for the LAMP and SCM groups havebeen undertaken by the mechanical workshop teamas well.

LibraryThe library at RRI was founded by Sir C V Raman andever since has served as a constant source of bothhighly specialized and general knowledge for theinstitute members. Throughout the years, the libraryhas continuously expanded trying to provideadequate literature for the growing research activitiesat RRI.

Currently, its total collection of books and boundjournals is close to 65,800. The library has anextensive collection of materials in the areas ofresearch conducted at RRI – astronomy andastrophysics, classical and quantum optics, softcondensed matter, theoretical physics, electronics,digital signal processing, computer science, etc. Thenon-book materials of the library include scientificslides, CD-ROMs, DVDs and audio and video tapes.

The RRI library is a partner in both FORSA and CSIR-DST consortia and the expansion of full text accessto online journals is one of its major priorities. It alsomaintains a digital repository of all publicationspublished by RRI members as well as students’ thesesand dissertations. Open Public Access Catalogue(OPAC) is available for access to readers within andoutside RRI. The library participates in inter librarynetworking activities with various other institutionslike the Indian Institute of Science, Indian Institute ofAstrophysics, Jawaharlal Nehru Centre for AdvancedScientific Research, National Aerospace Laboratories,National Centre for Biological Sciences, TIFR Centrefor Applicable Mathematics and others.

Last year, the library repository continued to grow. Itadded 456 books, most of which were scientific,

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but also included some of a more general nature:48 Hindi books, 25 gratis books and 19 non-bookmaterials. The library subscribed to 76 print journalsand 83 online journals. 609 bound volumes ofjournals were added to the library.

The library continued to provide need-basedinformation services to users and maintained liaisonwith many local and outside libraries. Varioussubscriptions through FORSA and the NationalKnowledge Resource Consortium of CSIR-DSTfacilitated enhanced access to over 4,000 onlinejournals.

Digitization of archival material, such as hand-writtenmanuscripts, letters and photos, has been taken upand will be uploaded to the RRI Digital Repository.Nearly 110 papers published during the year havebeen uploaded. The RRI Digital Repository currentlyholds 3,938 items.

Computer Facilities

The various computing needs of the differentresearch and development groups at RamanResearch Institute are handled by our computerdivision team. The computing facilities consist ofmulti-CPU multi-core systems accessed by users fromtheir desktops through a high speed internal LAN.

Application-specific software packages along withdevelopment tools are available on these platforms.The campus network consists of a switched Gigabitbackbone on fiber and wired 10/100 Mbps Ethernetto the desktops.

Further mobility is assured by the secured wirelessconnection available on the campuspremises. A dedicated 10 Mbps lineensures the constant connectivity tothe global Internet community. Acomputer center is also available in thelibrary for the needs of students, staffand visitors.

The computer facilities on campuscontinued to be upgraded andimproved during the last year. Theeight node cluster was replaced witha high performance computer clusterwith 16 nodes. System andapplication packages were upgraded,and the network security improved.Backup and storage requirements

were addressed to meet increased storage needs.

Operating system upgrades were undertaken for keyservers, and scientific and other application packageswere procured and upgraded. Wi-Fi access oncampus was made more secure by employing themore secure WPA2 protocol. Security aspects ofour servers were re-examined to reduce threats toour network from outside. Internet access wasshifted to the high speed link provided by theNational Knowledge Network.

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In addition, a two-day workshop on Parallel andDistributed Computing was organized in associationwith CDAC Bangalore.

CampusThe Raman Research Institute campus is located inthe northern part of Bangalore city. The campuscovers an area of around 20 acres, where thebustling noise of the fast growing metropolis givesway to the soothing sounds of nature, creating thenecessary peaceful environment for creative workand research. The campus hosts all theoffice buildings, laboratories, a canteen,guest house and the 10.4m telescopebut when walking around one is leftwith the impression that they are all tinyadditions to the prevailing naturalgarden.

Most of the campus was landscapedby Sir C V Raman and the RRI Trust isproud to enforce policies that protectits unique natural environment. Theguest house on campus has facilitiesto comfor tably accommodatedistinguished visitors and visitingacademics, including visiting doctoralstudents. A canteen is also present oncampus to provide meals to all guestsas well as lunch and refreshments to all RRIemployees. Various gatherings, visitor talks, informalmeetings, concerts and dinners take place at theVillage – an ethnically designed area providing awarm rustic touch to the overall atmosphere oncampus.

The building adjacent to the canteen houses a smallclinic where consultant medical practitioners payvisits at fixed hours on most working days of the

week. Sports activities are envisioned to be animportant part of campus life. Therefore, there aretwo badminton courts available for use by theresearch faculty, staff and students. Extensiverenovations of major facilities and buildings oncampus have been taking place during the lastcouple of years. The Auditorium in the Main buildingwas equipped with better lighting and soundtechnology, and while addressing the issues of waterseepage and de-stressing the building, it wasdecided while tackling these issues, to construct acreative space on the Library building rooftop. The

canteen building underwent major renovations tomodernize and upgrade it to provide quality serviceto the institute members and distinguished visitorsin a faster and more efficient manner.

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Academic

PhD ProgrammeRRI offers a PhD programme that gives enthusiasticand motivated students the opportunity to join theglobal research community. The unique atmosphereof intellectual freedom allows the students at RRI topursue their individual interests within the broad areasof research conducted at the Institute. As a result,students are challenged to engage their full creativepotential and develop the ability for conductingindependent research. Constant formal and informalinteractions with the faculty and other students takethe learning process outside of the classroom andindividuals’ office space, encouraging students tothink and question critically others’ and their ownunderstanding and knowledge. Such interactionsalso promote an open minded attitude towardsscience and research. Attendance at national andinternational conferences exposes RRI students to amuch larger and diverse research community wherethey get a perspective of what the “big picture” intheir field of research is.

Students at RRI are registered for a PhD degree withthe Jawaharlal Nehru University, New Delhi. RRI is alsoa participant in the Joint Astronomy Programme (JAP)with the Indian Institute of Science, Bangalore andthe Physics in Biology Programme with the NationalCentre for Biological Sciences, Bangalore. Furtherdetails about the PhD programme, admissionrequirements and process can be found on ourwebsite.

Currently, there are nearly 60 students from all overIndia enrolled in the PhD programme and conductingresearch with faculty members from the four groupsin the institute. Last year five PhD degrees wereawarded and five were submitted for review.

Post-Doctoral FellowshipProgrammeRRI offers a post doctoral fellowship programmewhich is open for applications throughout the year.The initial duration of the post doctoral fellowshipsis two years and is often extended to three years.Post-doctoral fellows work independently and havethe academic freedom of choice in research areaand collaboration.Even though postdoctoral fellows arenot required to workin any specificresearch programmeor be attached tospecific research staffof the Institute, it isdesirable that theyhave professionalresearch interest andproven track record inareas with significantoverlap or associationwith the ongoing andenvisaged activities atthe Institute.Par ticipation of thefellows in the academic activities of the Institute,

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programs

student supervision as co-guides and collaborationwith other research staff is highly encouraged.

Candidates who have already held at least oneposition as a post doctoral researcher can also applyfor a limited number of Pancharatnam Fellowshipsoffered at RRI. Applications are accepted throughoutthe year and the processing time takes between fourto six months. The selected candidates are awardedthe Pancharatnam Fellowship for a period of three

years.

Further details aboutthe Post Doctoraland Pancharatnamfellowships at RRIcan be found onthe websitewww.rri.res.in.

Currently, there aretwelve post doctoralfellows at RRI comingfrom across thecountry and abroad.Their researchbackground, diversescientific interestsand future goals playimportant role in the

overall academic and research dynamics of theinstitute.

Visiting Students ProgrammeRaman Research Institute places high importance onits Visiting Student Programme (VSP) which wasintroduced in 2007. VSP at RRI offers researchexperience to students, who are currently pursuingtheir undergraduate or master ’s studies. Theprogramme runs year-round and its duration rangesfrom 6 weeks up to one year depending onindividual cases. At the beginning a suitable projectis identified for each student. While working on theirprojects, VSP students are closely advised by aresearch faculty or scientific staff member of theInstitute. They are encouraged to interact with otherstaff members and graduate students learning theimportance of sharing knowledge and exchange ofideas among researchers. The programme isdesigned such that students get exposed to someof the real challenges in the world of scientificresearch and acquire important skills that would helpthem in their future research pursuits.

The Summer Student Programme at RRI is similar tothe Visiting Student Programme but it runs onlybetween May 1st and June 30th of each year. Itprovides the opportunity to upto twenty selectedcandidates to become involved in short termresearch projects under the guidance of a researchfaculty member.

Since the programme initiation, the number of VSPstudents has progressively increased through theyears. During the year, a total of 112 students fromdifferent parts of the country were part of the VSPat RRI. The duration of these programs rangedbetween six weeks to six months, and sometimes,even a whole year. All those interested to join theVSP at RRI should visit our website to learn moreabout the eligibility criteria and application process.

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People

Astronomy andAstrophysics

V RadhakrishnanV RadhakrishnanV RadhakrishnanV RadhakrishnanV Radhakrishnan (DistinguishedProfessor Emeritus) up to 3.3.2011Research Interests: neutron stars,pulsars, locomotionEmail: [email protected]

Ravi SubrahmanyanRavi SubrahmanyanRavi SubrahmanyanRavi SubrahmanyanRavi Subrahmanyan (RRI Director)Research Interests: observationalcosmology, extragalactic astronomy,antennas and signal processingEmail: [email protected]

N Udaya ShankarN Udaya ShankarN Udaya ShankarN Udaya ShankarN Udaya Shankar (Coordinator)Research Interests: sky surveys,detection of EOR, instrumentationand signal processing for radioastronomyEmail: [email protected]

Anish RAnish RAnish RAnish RAnish Roshioshioshioshioshi up to 7.6.2010Research Interests: the galaxy andinterstellar medium, instrumentationand signal processingEmail: [email protected]

R BhandariR BhandariR BhandariR BhandariR Bhandari up to 30.6.2010Research Interests: topologicalphases, polarization opticsEmail: [email protected]

Biman NathBiman NathBiman NathBiman NathBiman NathResearch Interests: cosmology andstructure formation, extragalacticastronomyEmail: [email protected]

RRI

research faculty

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Harish VHarish VHarish VHarish VHarish Vedanthamedanthamedanthamedanthamedantham (ResearchAssociate)Research Interests: epoch ofreionization, radio telescopeinstrumentation, synthesis imagingEmail: [email protected]

ShashikantShashikantShashikantShashikantShashikant (Post Doctoral Fellow)Research Interests: physicalcosmology, cosmic backgroundradiation, large-scale structure of theuniverseEmail: [email protected]

SiddharSiddharSiddharSiddharSiddharth Maluth Maluth Maluth Maluth Malu (Post DoctoralFellow)Research Interests: galaxy clusters,cosmic microwave backgroundEmail: [email protected]

Mayuri SMayuri SMayuri SMayuri SMayuri S (Research Associate)Research Interests: Antenna designfor radio astronomy, currentlyexploring the instrumentation aspectsfor X-ray astronomyEmail: [email protected]


RRRRReji Philipeji Philipeji Philipeji Philipeji PhilipResearch Interests: nonlinear optics,intense laser field interactions, laserinduced plasmasEmail: [email protected]

Hema RamachandranHema RamachandranHema RamachandranHema RamachandranHema RamachandranResearch Interests: quantumcomputing, light propagation inrandom media, novel opticalapplications of nanomaterialsEmail: [email protected]

Sadiq RangwalaSadiq RangwalaSadiq RangwalaSadiq RangwalaSadiq Rangwala (Coordinator)Research Interests: ultra coldmolecules, ion trapping, atoms andmolecules in external fieldsEmail: [email protected]

Andal NarayananAndal NarayananAndal NarayananAndal NarayananAndal NarayananResearch Interests: quantum optics,magneto-optical traps,electromagnetically inducedtransparencyEmail: [email protected]

Sunita SharSunita SharSunita SharSunita SharSunita Sharmamamamama (Post Doctoral Fellow)up to 20.8.2010Research Interests: ultrafast andnonlinear opticsEmail: [email protected]

Solomon IvanSolomon IvanSolomon IvanSolomon IvanSolomon Ivan (Post Doctoral Fellow)Research Interests: quantuminformation theory, theory ofentanglementEmail: [email protected]


Sandeep Kumar Sandeep Kumar Sandeep Kumar Sandeep Kumar Sandeep Kumar (Coordinator)Research Interests: chemical synthesisof liquid crystals and theirapplicationsEmail: [email protected]

Raghunathan V ARaghunathan V ARaghunathan V ARaghunathan V ARaghunathan V AResearch Interests: Amphiphilicsystems, membranes, self assemblyand phase behaviour of surfactantpolyelectrolyte complexesEmail: [email protected]

ArArArArArun Run Run Run Run RoyoyoyoyoyResearch Interests: Phase transitionsand electro-optic properties ofliquid crystals, physics ofnanomaterials and nanocompositesEmail: [email protected]

Pratibha RPratibha RPratibha RPratibha RPratibha RResearch Interests: liquid crystals,nanocompositesEmail: [email protected]

A A DeshpandeA A DeshpandeA A DeshpandeA A DeshpandeA A DeshpandeResearch Interests: neutron stars,pulsars and transients, instrumentationand signal processingEmail: [email protected]

B RameshB RameshB RameshB RameshB RameshResearch Interests: diffuse matter inour and other galaxies, analog anddigital signal processing, (sub)millimeterwave telescopesEmail: [email protected]

S SridharS SridharS SridharS SridharS SridharResearch Interests: dynamo actiondue to turbulence in shear flows,MHD turbulence, stellar dynamics ingalactic nucleiEmail: [email protected]

C R SubrahmanyaC R SubrahmanyaC R SubrahmanyaC R SubrahmanyaC R Subrahmanya (Visiting Professorfrom 1.12.2010)Research Interests: cosmology,extragalactic radio sources, surveys,instrumentation and signal processingEmail: [email protected]

Biswajit PBiswajit PBiswajit PBiswajit PBiswajit PaulaulaulaulaulResearch Interests: X-ray binaries,transients, X-ray instrumentation andsignal processingEmail: [email protected]

Shiv Kumar SethiShiv Kumar SethiShiv Kumar SethiShiv Kumar SethiShiv Kumar SethiResearch Interests: cosmology andstructure formation, reionization era,cosmological magnetic fieldsEmail: [email protected]

Dwarakanath K SDwarakanath K SDwarakanath K SDwarakanath K SDwarakanath K SResearch Interests: extragalacticastronomy, clusters of galaxies, haloand relic radio sourcesEmail: [email protected]

Lakshmi SaripalliLakshmi SaripalliLakshmi SaripalliLakshmi SaripalliLakshmi Saripalli (RRI Trust fundedposition)Research Interests: morphology andlife-cycle of radio galaxies, surveysEmail: [email protected]

PEOPLE82

Lakshminarayanan VLakshminarayanan VLakshminarayanan VLakshminarayanan VLakshminarayanan VResearch Interests: Electrochemistryof surfaces and interfaces, electrontransfer processesEmail: [email protected]

Ranjini BandyopadhyayRanjini BandyopadhyayRanjini BandyopadhyayRanjini BandyopadhyayRanjini BandyopadhyayResearch Interests:Copolymersurfactant interactions,drug delivery systems, non-Newtonian flows, gels, soft glasses,granular mediaEmail: [email protected]

Ruckmongathan T NRuckmongathan T NRuckmongathan T NRuckmongathan T NRuckmongathan T NResearch Interests: liquid crystaldisplays, addressing, controllersEmail: [email protected]

YYYYYashodhan Hatwalneashodhan Hatwalneashodhan Hatwalneashodhan Hatwalneashodhan HatwalneResearch Interests: Phenomenologicaltheory of liquid crystals, membranesand polymer crystallizationEmail: [email protected]

Pramod PullarkatPramod PullarkatPramod PullarkatPramod PullarkatPramod PullarkatResearch Interests: Biophysics in celldynamics, cell cytoskeleton,transport and dynamics in axonsEmail: [email protected]

B K SadashivaB K SadashivaB K SadashivaB K SadashivaB K Sadashiva (INSA Senior Scientist)Research Interests: chemistry of liquidcrystalline materials, intelligent designand synthesis of mesogensEmail: [email protected]

N V MadhusudhanaN V MadhusudhanaN V MadhusudhanaN V MadhusudhanaN V Madhusudhana (INSA SeniorScientist)Research Interests: soft condensedmatter, liquid crystalsEmail: [email protected]

Soma DattaSoma DattaSoma DattaSoma DattaSoma Datta (Post Doctoral Fellow) upto 31.5.2010Research Interests: Phase transitionsand electro optics of liquid crystals

Mahesh Kumar VMahesh Kumar VMahesh Kumar VMahesh Kumar VMahesh Kumar Varia aria aria aria aria (Post DoctoralFellow)Research Interests: To synthesize BluePhase forming materials and Dodeca-substituted-hexabenzenecoronenediscoticsEmail: [email protected]

Meenal Gupta Meenal Gupta Meenal Gupta Meenal Gupta Meenal Gupta (Post Doctoral Fellow)up to 31.12.2010Research Interests: physicalproperties of liquid crystals usingdifferent experimental techniquesEmail: [email protected]

Kavitha GKavitha GKavitha GKavitha GKavitha GResearch Interests: structure andphase behaviour of liquid crystalsEmail: [email protected]

Theoretical Physics

Abhishek DharResearch Interests: nonequilibriumstatistical mechanics, soft condensedmatter physicsEmail: [email protected]

Sanjib Sabhapandit Sanjib Sabhapandit Sanjib Sabhapandit Sanjib Sabhapandit Sanjib Sabhapandit (Coordinator)Research Interests: statistical physics,extreme value statisticsEmail: [email protected]

Joseph SamuelJoseph SamuelJoseph SamuelJoseph SamuelJoseph SamuelResearch Interests: general relativity,optics, soft condensed matterphysicsEmail: [email protected]

Madan RaoMadan RaoMadan RaoMadan RaoMadan RaoResearch Interests: soft condensedmatter physics, physics in biologyEmail: [email protected]

B R IyerB R IyerB R IyerB R IyerB R IyerResearch Interests: general relativity,gravitational wavesEmail: [email protected]

Sumati SurSumati SurSumati SurSumati SurSumati SuryayayayayaResearch Interests: classical andquantum gravityEmail: [email protected]

Madhavan VMadhavan VMadhavan VMadhavan VMadhavan VaradarajanaradarajanaradarajanaradarajanaradarajanResearch Interests: classical andquantum gravityEmail: [email protected]

N KumarN KumarN KumarN KumarN Kumar (Emeritus Professor)Research Interests: randomness,dissipation, and decoherence incondensed matterEmail: [email protected]

SupurSupurSupurSupurSupurna Sinha na Sinha na Sinha na Sinha na Sinha (Research Associate)Research interests: nonequilibriumstatistical mechanics, soft condensedmatter physicsEmail: [email protected]

Alok Laddha Alok Laddha Alok Laddha Alok Laddha Alok Laddha (Post Doctoral Fellow)up to 23.6.2010Research Interests: loop quantumgravityEmail: [email protected]

PPPPPoonam Mehta oonam Mehta oonam Mehta oonam Mehta oonam Mehta (Post DoctoralFellow)Research Interests: neutrino physicsand geometric phaseEmail: [email protected]

RRRRRoman Sverdlov oman Sverdlov oman Sverdlov oman Sverdlov oman Sverdlov (Post DoctoralFellow)Research Interests: quantum gravity,causal set theoryEmail: [email protected]

RRRRRyuichi Fyuichi Fyuichi Fyuichi Fyuichi Fujita ujita ujita ujita ujita (Post Doctoral Fellow)Research Interests: gravitationalwaves, general relativityEmail: [email protected]

SamarSamarSamarSamarSamarth Chandra th Chandra th Chandra th Chandra th Chandra (Post DoctoralFellow)Research Interests: statisticalmechanics, spin glasses, biophysicsEmail: [email protected]

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Radio Astronomy Lab

P G [email protected]

K [email protected]

M S [email protected]

B S [email protected]

M R Gopala [email protected]

P A [email protected]

S [email protected]

S [email protected]

C [email protected]

H N [email protected]

T [email protected]

K B Raghavendra [email protected]

A [email protected]

P [email protected]

G [email protected]

R [email protected]

S [email protected]

T S [email protected]

K R [email protected]

K S [email protected]

P V [email protected]

P S Sasi [email protected]


M S [email protected]

Soft Consensed Matter

Mohammed [email protected]

N Ravi [email protected]

A R [email protected]

H T [email protected]

H [email protected]

K N [email protected]

D [email protected]

A [email protected]

Mechanical EngineeringServices

C M Ateequlla, [email protected]

M AchankunjuI Charles PaulV DhamodharanR Durai ChelvanR ElumalaiK O FrancisV Gokula ChandranN GopalM ManiK M MohandasV NagarajanN NarayanaswamyT PuttaswamyD SunandM Suresh KumarV Venu (up to 31.7.2010)

Computers

R Nanda Kumar, [email protected]

Jacob [email protected]

B [email protected]

S Krishna [email protected]

Gauribidanur Telescope

H A Aswathappa

scientific/technical staff

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Astronomy andAstrophysics

PPPPPeeyush Prasadeeyush Prasadeeyush Prasadeeyush Prasadeeyush PrasadResearch Interests: radio astronomyinstrumentationEmail: [email protected]: C R Subrahmanya

Raju Ramakrishna Baddi Raju Ramakrishna Baddi Raju Ramakrishna Baddi Raju Ramakrishna Baddi Raju Ramakrishna Baddi (up to31.7.2010)Research Interests: Physics ofinterstellar medium, observationaland theoretical astrophysicsEmail: [email protected]: Anish Roshi

Ruta KaleRuta KaleRuta KaleRuta KaleRuta KaleResearch Interests: Galaxy clusters,Magnetic fields in intracluster mediumEmail: [email protected]: K S Dwarakanath

WWWWWasim Rajaasim Rajaasim Rajaasim Rajaasim RajaResearch Interests: neutron stars,pulsars & transients, instrumentationand signal processingEmail: [email protected]: A A Deshpande

YYYYYogesh Maan ogesh Maan ogesh Maan ogesh Maan ogesh Maan (JAP student)Research Interests: neutron stars,pulsars & transients, instrumentationand signal processingEmail: [email protected]: A A Deshpande

Mamta Gulati Mamta Gulati Mamta Gulati Mamta Gulati Mamta Gulati (JAP student)Research Interests: Waves anddynamics in disksEmail: [email protected]: S Sridhar

Nishant Kumar Singh Nishant Kumar Singh Nishant Kumar Singh Nishant Kumar Singh Nishant Kumar Singh (JAP student)Research Interests: AstrophysicalflowsEmail: [email protected]: S Sridhar

Kanhaiya Lal PKanhaiya Lal PKanhaiya Lal PKanhaiya Lal PKanhaiya Lal PandeyandeyandeyandeyandeyResearch Interests: cosmology andstructure formation, reionization eraEmail: [email protected]: Shiv Sethi

Nipanjana PNipanjana PNipanjana PNipanjana PNipanjana Patra atra atra atra atra (JAP student)Research Interests: Cosmology, global21 cm, EOREmail: [email protected]: Ravi Subrahmanyan

Chandreyee Maitra Chandreyee Maitra Chandreyee Maitra Chandreyee Maitra Chandreyee Maitra (JAP student)Research Interests: X ray Polarisation ,polarimeter, spectral studies of X raybinariesEmail: [email protected]: Biswajit Paul

Kshitij Thorat Kshitij Thorat Kshitij Thorat Kshitij Thorat Kshitij Thorat (JAP student)Research Interests: Radio Astronomy,optical astronomy, active galacticnucleus (AGN) evolutionEmail: [email protected]: Ravi Subrahmanyan/LakshmiSaripalli

Mahavir SharMahavir SharMahavir SharMahavir SharMahavir SharmamamamamaResearch Interests: cosmology andstructure formation, extragalacticastronomyEmail: [email protected]: Biman Nath

Lijo Thomas George Lijo Thomas George Lijo Thomas George Lijo Thomas George Lijo Thomas George (from26.7.2010)Research Interests: Cosmology –Baryon Acoustic OscillationsEmail: [email protected]

PhD studentsBharBharBharBharBharti Mehra ti Mehra ti Mehra ti Mehra ti Mehra (from 6.8.2010)Research Interests: X-ray binaries andmodelling phenomenon (like bursts)to understand X-ray binariesEmail: [email protected]

Nazma Sayeda Nazma Sayeda Nazma Sayeda Nazma Sayeda Nazma Sayeda (JAP student; from19.8.2010)Research Interests: X- ray binaries andX-ray luminosity functions of galaxiesEmail: [email protected]

K K Harinarayanan K K Harinarayanan K K Harinarayanan K K Harinarayanan K K Harinarayanan (JAP student; from25.8.2010 to 18.5.2011)


Seunghyun LeeSeunghyun LeeSeunghyun LeeSeunghyun LeeSeunghyun LeeResearch Interests: Atom-IoninteractionEmail: [email protected]: Sadiq Rangwala

Archana SharArchana SharArchana SharArchana SharArchana Sharma ma ma ma ma (up to 31.7.2010)Research Interests: quantuminteractions with cold atoms,molecules and ionsEmail: [email protected]: Hema Ramachandran/AndalNarayanan

Arijit SharArijit SharArijit SharArijit SharArijit SharmamamamamaResearch Interests: laser cooling ofatoms, cold molecules, opticallattices and BECEmail: [email protected]: Sadiq Rangwala

Deepak PDeepak PDeepak PDeepak PDeepak PandeyandeyandeyandeyandeyResearch Interests: laser cooling ofatoms, quantum computationEmail: [email protected]: Hema Ramachandran

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Nandan SatapathyNandan SatapathyNandan SatapathyNandan SatapathyNandan SatapathyResearch Interests: cold atoms, BEC,optical latticesEmail: [email protected]: Hema Ramachandran

Ravi KRavi KRavi KRavi KRavi KResearch Interests: laser cooling ofatoms, trapping of ions, atom-ioninteraction, molecule formationmechanismsEmail: [email protected]: Sadiq Rangwala

Suchand Sandeep Suchand Sandeep Suchand Sandeep Suchand Sandeep Suchand Sandeep (up to31.7.2010)Research Interests: plasma physics,intense laser matter interactions,nonlinear opticsEmail: [email protected]: Reji Philip

Jagdish Chandra JoshiJagdish Chandra JoshiJagdish Chandra JoshiJagdish Chandra JoshiJagdish Chandra JoshiResearch Interests: quantumchemistryEmail: [email protected]: Sadiq Rangwala

Jyothi SJyothi SJyothi SJyothi SJyothi SResearch Interests: quantuminteractions of atoms, molecules andionsEmail: [email protected]: Sadiq Rangwala

TTTTTridib Rayridib Rayridib Rayridib Rayridib RayResearch Interests: quantuminteractions of atoms, molecules andionsEmail: [email protected]: Sadiq Rangwala


Bharat Kumar Bharat Kumar Bharat Kumar Bharat Kumar Bharat Kumar (up to 31.7.2010)Research Interests: Electrochemistryof surfaces and interfaces, electrontransfer processesEmail: [email protected]: V Lakshminarayanan

Bibhu Ranjan Sarangi Bibhu Ranjan Sarangi Bibhu Ranjan Sarangi Bibhu Ranjan Sarangi Bibhu Ranjan Sarangi (up to7.5.2010)Research Interests: ExperimentalBiophysics, Membrane PhysicsEmail: [email protected]: V A Raghunathan

Brindaban Kundu Brindaban Kundu Brindaban Kundu Brindaban Kundu Brindaban Kundu (up to 9.8.2010)Research Interests: liquid crystals,nanocompositesEmail: [email protected]: R Pratibha

Hari Krishna Bisoyi Hari Krishna Bisoyi Hari Krishna Bisoyi Hari Krishna Bisoyi Hari Krishna Bisoyi (up to 5.5.2010)Research Interests: chemistry of liquidcrystalsEmail: [email protected]: Sandeep Kumar

A JayakumarA JayakumarA JayakumarA JayakumarA JayakumarResearch Interests: theory of liquidcrystalsEmail: [email protected]: Yashodhan Hatwalne

D H NagarajuD H NagarajuD H NagarajuD H NagarajuD H Nagaraju (up to 25.6.2010)Research Interests: Electrochemistryof surfaces and interfaces, electrontransfer processesEmail: [email protected]: V Lakshminarayanan

Radhakrishnan A VRadhakrishnan A VRadhakrishnan A VRadhakrishnan A VRadhakrishnan A VResearch Interests: amphiphilicsystems, surfactantsEmail: [email protected]: V A Raghunathan

Mohammed Arif KamalMohammed Arif KamalMohammed Arif KamalMohammed Arif KamalMohammed Arif KamalResearch Interests: ModelmembranesEmail: [email protected]: V A Raghunathan

Antara PAntara PAntara PAntara PAntara PalalalalalEmail: [email protected]: V A Raghunathan

S RadhikaS RadhikaS RadhikaS RadhikaS RadhikaResearch Interests: liquid crystals,nanocompositesEmail: [email protected]

Advisor: R Pratibha

S MadhukarS MadhukarS MadhukarS MadhukarS MadhukarResearch Interests: surfactants,amphiphilic systemsEmail: [email protected]: V A Raghunathan

Rajib BasakRajib BasakRajib BasakRajib BasakRajib BasakResearch Interests: Dynamics andRheology of Soft Glassy MaterialsEmail: [email protected]: Ranjini Bandyopadhyay

CH Laxmi Kishore SagarCH Laxmi Kishore SagarCH Laxmi Kishore SagarCH Laxmi Kishore SagarCH Laxmi Kishore Sagar (from29.7.2010)Research Interests: Synthesis ofQuantum Dots and theirincorporation into liquid crystals,synthesis of novel liquid crystalsEmail: [email protected]: Sandeep Kumar

Anu Simon Anu Simon Anu Simon Anu Simon Anu Simon (from 27.7.2010)Research Interests: Electrochemistryof surfaces and interfaces, electrontransfer processes of thin filmsEmail: [email protected]: V Lakshminarayanan

Debasish SahaDebasish SahaDebasish SahaDebasish SahaDebasish SahaResearch Interests: Structure andDynamics of Colloids, Rheology ofSoft Glassy Material and FlowBehaviour of Soft SolidsEmail: [email protected]: Ranjini Bandyopadhyay

RRRRRenu Vishavkarenu Vishavkarenu Vishavkarenu Vishavkarenu VishavkarmamamamamaResearch Interests: biophysicsEmail: [email protected]: Pramod Pullarkat

Santosh Prasad GuptaSantosh Prasad GuptaSantosh Prasad GuptaSantosh Prasad GuptaSantosh Prasad GuptaResearch Interests: surfactants,amphiphilic systemsEmail: [email protected]: V A Raghunathan

Seshagiri RaoSeshagiri RaoSeshagiri RaoSeshagiri RaoSeshagiri RaoResearch Interests: biophysicsEmail: [email protected]

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Advisor: Pramod Pullarkat

P R VP R VP R VP R VP R VenkatramananenkatramananenkatramananenkatramananenkatramananResearch Interests: Liquid Crystals,MembranesEmail: [email protected]: Yashodhan Hatwalne

RakRakRakRakRakesh Kumar Pesh Kumar Pesh Kumar Pesh Kumar Pesh Kumar PandeyandeyandeyandeyandeyResearch Interests: Electrochemistry,Material science, ElectrocatalysisEmail: [email protected]: V Lakshminarayanan

Satyam Kumar GuptaSatyam Kumar GuptaSatyam Kumar GuptaSatyam Kumar GuptaSatyam Kumar GuptaResearch Interests: liquid crystalsynthesis and characterisationEmail: [email protected]: Sandeep Kumar

P Suresh Kumar P Suresh Kumar P Suresh Kumar P Suresh Kumar P Suresh Kumar (up to 31.7.2010)Research Interests: Electrochemistryof surfaces and interfaces, electrontransfer processesEmail: [email protected]: V Lakshminarayanan

TTTTTripta Bhatiaripta Bhatiaripta Bhatiaripta Bhatiaripta BhatiaResearch Interests: theory of liquidcrystalsEmail: [email protected]: Yashodhan Hatwalne

Anagha DatarAnagha DatarAnagha DatarAnagha DatarAnagha DatarResearch Interests: biophysicsEmail: [email protected]: Pramod Pullarkat

P K ShabeebP K ShabeebP K ShabeebP K ShabeebP K ShabeebResearch Interests: rheology of softmatter systemsEmail: [email protected]: V.A.Raghunathan

AAAAAvinash B Svinash B Svinash B Svinash B Svinash B SResearch Interests: Electrochemistryof surfaces and interfaces, electrontransfer processesEmail: [email protected]: Sandeep Kumar

Samim AliSamim AliSamim AliSamim AliSamim AliResearch Interests: rheology of softmatter systemsEmail: [email protected]

Advisor: Ranjini Bandyopadhyay

Swamynathan KSwamynathan KSwamynathan KSwamynathan KSwamynathan KResearch Interests: chemistry of liquidcrystalsEmail: [email protected]: Sandeep Kumar

Theoretical Physics

Anirban PAnirban PAnirban PAnirban PAnirban PolleyolleyolleyolleyolleyResearch Interests: soft condensedmatterEmail: [email protected]: Madan Rao

Anupam Kundu Anupam Kundu Anupam Kundu Anupam Kundu Anupam Kundu (up to 9.8.2010)Research Interests: soft condensedmatter and statistical mechanicsEmail: [email protected]: Abhishek Dhar

Chandrakant Mishra Chandrakant Mishra Chandrakant Mishra Chandrakant Mishra Chandrakant Mishra (JAP student)Research Interests: gravitationalradiation and general relativityEmail: [email protected]: Bala Iyer

Pragya SrivastavaPragya SrivastavaPragya SrivastavaPragya SrivastavaPragya SrivastavaResearch Interests: biological systems– theoretical studies of activeprocesses in living cellsEmail: [email protected]: Madan Rao

Suchana SethSuchana SethSuchana SethSuchana SethSuchana SethResearch Interests: Nonequilibriumstatistical mechanicsEmail: [email protected]: Abhishek Dhar

Anjan RAnjan RAnjan RAnjan RAnjan RoyoyoyoyoyResearch Interests: statisticalmechanicsEmail: [email protected]: Abhishek Dhar

Chaitra Shreepad HegdeChaitra Shreepad HegdeChaitra Shreepad HegdeChaitra Shreepad HegdeChaitra Shreepad HegdeResearch Interests: theoreticalphysics, statistical mechanicsEmail: [email protected]

Advisor: Abhishek Dhar

Prasad V VPrasad V VPrasad V VPrasad V VPrasad V VResearch Interests: theoreticalphysics, statistical mechanicsEmail: [email protected]: Sanjib Sabhapandit

Suman Gaurab DasSuman Gaurab DasSuman Gaurab DasSuman Gaurab DasSuman Gaurab DasResearch Interests: theoreticalphysics, statistical mechanicsEmail: [email protected]: Abhishek Dhar

ArArArArArnab Pnab Pnab Pnab Pnab PalalalalalResearch Interests: theoreticalphysics, statistical mechanicsEmail: [email protected]: Sanjib Sabhapandit

visiting scientistsAstronomy andAstrophysics

P SreekumarTarun Deep SainiVinod Krishan


R SrikanthR Srinivasan

Radio Astronomy Lab

A Krishnan

Adjunct Professors

Ramanath CowsikAnders KastbergRon Ekers

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Dr. K Kasturirangan Member, Planning CommissionChairman

Prof. P K Kaw Director, Institute of Plasma ResearchGandhinagar 382 428

Prof. V Radhakrishnan Member-Secretary(up to 3.3.2011) Raman Research Institute Trust

Bangalore 560 080

Dr.T Ramasami Secretary, Ministry of Science & TechnologyDepartment of Science & TechnologyNew Delhi 110 016

Prof. Ravi Subrahmanyan Director, Raman Research InstituteBangalore 560 080

Prof. O Siddiqi National Centre for Biological SciencesTata Institute of Fundamental ResearchBangalore 560 065

Ms. Sheila Sangwan Additional Secretary & Financial AdvisorMinistry of Science & TechnologyDepartment of Science & Technology, New Delhi 110 016

Prof. A K Sood Physical & Mathematical Sciences DivisionIndian Institute of ScienceBangalore 560012

Finance CommitteeDr. K Kasturirangan Member, Planning CommissionChairman

Ms. Sheila Sangwan Additional Secretary & Financial AdvisorMinistry of Science & TechnologyDepartment of Science & Technology, New Delhi 110 016

Prof. V Radhakrishnan Member-Secretary(up to 3.3.2011) Raman Research Institute Trust

Bangalore 560 080

Prof. Ravi Subrahmanyan Director, Raman Research InstituteBangalore 560 080

Council

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other staffAdministrationK Krishnama RajuAdministrative [email protected]

K RaghunathaDeputy Administrative [email protected]

Marisa D’[email protected]

K [email protected]

S R [email protected]

V [email protected]

R [email protected]

V S [email protected]

G V Indira

Group Secretaries

Astronomy and AstrophysicsAstronomy and AstrophysicsAstronomy and AstrophysicsAstronomy and AstrophysicsAstronomy and AstrophysicsVidyamani [email protected]

SofSofSofSofSoft Condensed Mattert Condensed Mattert Condensed Mattert Condensed Mattert Condensed MatterRadhakrishna [email protected]

Light and Matter PhysicsLight and Matter PhysicsLight and Matter PhysicsLight and Matter PhysicsLight and Matter PhysicsS Harini [email protected]

Theoretical PhysicsTheoretical PhysicsTheoretical PhysicsTheoretical PhysicsTheoretical PhysicsG [email protected]

RRRRRAL LabAL LabAL LabAL LabAL LabMamatha Bai [email protected]

AccountsP V SubramanyaAccounts Officer

V RaghunathR RameshInternal Auditor

PurchaseC N Ramamurthy (In-charge)M PremaG Gayathri

Stores

B Srinivasa Murthy (In-charge)M V Subramanyam

LibraryS GeethaHanumappaKiran P SavanurM ManjunathM N NagarajVrinda J BenegalRaju Varghese (Graphic Arts)

Support StaffK ChowdasettyC Elumalai

UpkeepHanumanthaJayammaK N KawalappaD KrishnaC LakshmammaT MahadevaT MuraliNarayanaSidde GowdaV Venkatesh

Estates and BuildingsG B Suresh (Civil Engineer)R Sasidharan (Supervisor)R Anantha Subba Rao (Consultant)S Anantha RamanK BhoopalanGunashekarC HaridasK PalaniM RajagopalK G NarasimhaluM RameshA RamannaRanjithamma

SecurityC N Ganapathy (In-charge)B M BasavarajaiahU A EarappaH GangaiahKeshavamurthySureshaK KrishnappaMunihobalaiahK PushparajO M RamachandraG RamakrishnaM SannaiahH VaderappaS Nagaraja (Consultant)

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TransportC N Ganapathy (In-charge)M K Raju KuttyM BalaramaK MohananG PrakashRahamath PashaG RajaM Venkateshappa

Amenities(Guest House & Hostels)(Guest House & Hostels)(Guest House & Hostels)(Guest House & Hostels)(Guest House & Hostels)ShivamalluMangala SinghMuniratnaT NagannaN Narayanappa (In charge)D B PadmavathyP C PrabhakarN PuttaswamyA RajuN SeetharamUmaSharadammaYashodhaSrihari Prahlad (GHC)

HorticultureBylappaGovind K KundagolLingegowdaD MahalingaMailarappaMarappaD MunirajaS MunirajuRahamathulla KhanRangalakshmiVaralakshmi

MedicalConsultant Paediatrician:Dr. M R BaligaConsultant Physician:Dr. B V Sanjay RaoTechnician:R Shanthamma

CarpentryM GopinathL Muthu (Expired 9.2.2011)

Gauribidanur TelescopeSupporSupporSupporSupporSupport Stafft Stafft Stafft Stafft StaffBheema NaikGangaramM MuniyappaPapannaPrahallada RaoR P Ramji NaikRanoji RaoShivarudraradhyaThippannaVenkataswamyN R Srinath

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publications

The institute publishes the research activities carried outover the year in national and international peer-reviewedjournals. Each of the four research groups at RRI findstheir work published in distinguished journals that focuson their specific research area. For the Theoretical Physicsgroup these include, but are not limited to, PhysicalReview, Classical and Quantum Gravity, Journal of Physics,Journal of Statistical Mechanics and Biophysics Journal.Research faculty and students from the Soft CondensedMatter group have their work published in journals likePhysical Review, Liquid Crystals, Journal of PhysicalChemistry, Journal of Chemical Sciences, Journal ofApplied Physics, European Physical Journal, Journal ofNanoscience and Nanotechnology and many more.

Publications of the Light and Matter Physics group at RRIcan be found in Physical Review, Journal ofNanophotonics, Optical Express and Canadian Journalof Physics. The astronomers and astrophysicists at RRIuse the Physical Review, Monthly Notices of the RoyalAstronomical Society, Astrophysical Journal, the Journalof Astrophysics and Astronomy and others as a meansto share their work with the scientific community aroundthe world. One hundred and four papers featuring RRImembers as their authors and/or co-authors werepublished during the year. There were 14 publicationsin conference proceedings and 40 (38 in journals and2 in conference proceedings) publications are in press.Members at the institute expand and diversify their workbeyond the scope of highly specialized technical andscience journals by publishing books and/or articles forpopular science magazines. (Appendix I)

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Activitiesother

ConferencesConferences and visits to various institutions at homeand abroad play a significant role in the researchactivities of the institute members. Such eventsprovide opportunities for idea exchange and areoften a starting point for future fruitful collaborationswith other researchers from various institutions withinIndia and abroad. Last year, faculty and students ofthe institute attended numerous conferences in India,Australia, Israel, Japan, the US and all over Europe.

In addition, lectures and invited talks were given at avariety of workshops, international programs,multinational project meetings and training programs.Members of the Institute visited colleges around thecountry and specially organized workshops ondifferent science and research topics to deliverlectures, talks and presentations.

A full list of the conferences visited by each of theinstitute members is provided in Appendix II.

Seminars and ColloquiaThursday colloquia are one of the numerous activitiespromoted at the Institute as a way to increase theinteractions between the various research groupswithin RRI as well as those between RRI membersand invited speakers and their institutions. Apart fromcovering relevant science topics, the colloquia oftenintroduce new and interesting themes from variousother disciplines.

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During the last year, the Institute invited speakers fromall over India, the US, Japan, Korea, Singapore,Australia, Italy, Denmark, Germany, Switzerland andthe UK to deliver the Thursday colloquia. The topicsincluded the likes of “Quantum Games”, “Lookingfor Primordial Non-Gaussian Signals in the CMB”,“Nanocatalysts and Their Applications”, The EvolutionAnimal Grouping and Collective Motion”, and “FromDarkness, Light: Computing Cosmic Reionization”.

A complete list of the speakers, their lecture topicsand when they visited RRI is given in Appendix III.

Seminars at the Institute are often delivered by visitingfaculty and researchers. Unlike colloquia, seminarsare intended to deepen the understanding andgenerate discussions on a very specific researchtheme. Usually, the topics cover the current progressof collaborative projects between RRI and thevisitor’s institution, or themes of particular interestto RRI members.

A list of the visiting research faculty and researchersto RRI during the last year, is given in Appendix IV.

Visiting ScholarsA high priority is given to increasing thestream of visiting scholars to the institute. Intoday ’s high-tech world of globalconnectivity the academic and researchcommunity is more open then ever before.Maintaining nationally and internationallyopen environment is crucial for the successof every research institution.

Members at RRI recognize that and worktirelessly toward creating moreoppor tunities for larger number ofscientists, researchers and engineers to visitthe institute, contribute new ideas and skills,while benefitting from the expertise of ourown members. Visits at RRI can last fromfew days to few months and often lead to

impor tant collaborative results and/or theconception of new interesting projects.

Last year , there were more than 100 scholars whovisited RRI from 18 Indian and more than 30international institutions. RRI is happy to have so manyfriends and thanks all of them for making theenvironment in the institute so diverse, dynamic andvibrant.

A list of all visitors, where they come from and whenthey visited RRI can be found in Appendix IV.

Journal ClubThe Journal Club at RRI, initiated in 1981, aims atdrawing the attention of members of the Institute toexciting and interesting papers that appear inscientific literature. Given the large numbers of paperspublished these days, it is nearly impossible for anindividual to keep track of developments outsidetheir research specialities. The Journal Club tries topartly remedy this situation by presentations of avariety of recent papers of general interest.

The last Journal Club slot of the year is traditionallyreserved to review the year’s Nobel Prize Award in

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Physics. While speakers present their selectedpapers, informal discussions, questions anddemonstrations are strongly encouraged as oftenthey are the seeds of better understanding that canlead to better quality research.

A list of the papers reviewed during the Journal Clubmeetings last year is attached to the annual reportas Appendix V.

Hindi CellRRI has initiated its efforts to reach the targets fixedby the official language policy of the Governmentof India. In this direction, training in Hindi wascontinued in addition to holding workshops andpar ticipating in activities in the neighbouringinstitutions. Efforts were also made to incorporateHindi in the account statements and to adopt thesame in purchase reports. Efforts to meet the targetslaid down by the Official Language Policy in theadministration of the Institute were intensified. Effortsto make the targets laid down by the OfficialLanguage Policy in the administration of the institutewere intensified.

ReservationsThe institute follows the reservation policy as isfollowed by the Government of India and scientificdepar tments like Depar tment of Space andDepartment of Atomic Energy.

OthersThe RRI community is involved in various otheractivit ies ranging from organizing specialconferences, meetings and workshops, and invitingcollege students to the campus, to having formaland informal dinners, sport tournaments, and avariety of cultural programs both with invitedperformers or members of RRI itself. Such activitiesare considered to be an integral par t of themembers’ experience at the institute. Other eventsand activities such as in-house meetings, concerts,formal faculty farewell dinners, college visits andmore continue to enrich and diversify the academiclife and atmosphere at the Raman Research Institute.

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