By:Farrin Payandeh University of Payame Noor, Tabriz,Iran XVII European Workshop on String Theory...

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By:Farrin Payandeh University of Payame Noor, Tabriz,Iran XVII European Workshop on String Theory 2011 Italy, Padua September 2011

Transcript of By:Farrin Payandeh University of Payame Noor, Tabriz,Iran XVII European Workshop on String Theory...

Page 1: By:Farrin Payandeh University of Payame Noor, Tabriz,Iran XVII European Workshop on String Theory 2011 Italy, Padua September 2011.

By:Farrin PayandehUniversity of Payame

Noor, Tabriz,Iran

XVII European Workshop on String Theory 2011

Italy, Padua

September 2011

Page 2: By:Farrin Payandeh University of Payame Noor, Tabriz,Iran XVII European Workshop on String Theory 2011 Italy, Padua September 2011.

Dirac’s equation and the sea of negative energy. Standard quantum field theory leading to the infinites. Renormalization : Sweeping the infinites under the rug. EPR Paradox and Antiparticles. Quantum Mechanics in complex spacetime. The Miracle of creation. Conservation of Angular momentum(a.k.a. “The photon”).

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Page 3: By:Farrin Payandeh University of Payame Noor, Tabriz,Iran XVII European Workshop on String Theory 2011 Italy, Padua September 2011.

Neglecting negative Energies:

“At what cost?”

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Page 4: By:Farrin Payandeh University of Payame Noor, Tabriz,Iran XVII European Workshop on String Theory 2011 Italy, Padua September 2011.

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Case Study

P. A. M. Dirac: Bakerian Lecture , Proceedings of the Royal Society A (1941)

Page 5: By:Farrin Payandeh University of Payame Noor, Tabriz,Iran XVII European Workshop on String Theory 2011 Italy, Padua September 2011.

Quantization of the minimally coupled scalar field and calculating

the gravitaton two point function in de Sitter spacetime:

Breaking of the covariance.

(a) Appearance of the infrared divergence.

(b) Covariant Quantization adding Negative Frequency States and

Free of divergence graviton field operator in krein Space

Field operator in Krein space: ))x()x((2

1)x( np

Page 6: By:Farrin Payandeh University of Payame Noor, Tabriz,Iran XVII European Workshop on String Theory 2011 Italy, Padua September 2011.

Krein QFT calculations in Minkowski spacetimeKrein QFT calculations in Minkowski spacetime

Page 7: By:Farrin Payandeh University of Payame Noor, Tabriz,Iran XVII European Workshop on String Theory 2011 Italy, Padua September 2011.
Page 8: By:Farrin Payandeh University of Payame Noor, Tabriz,Iran XVII European Workshop on String Theory 2011 Italy, Padua September 2011.
Page 9: By:Farrin Payandeh University of Payame Noor, Tabriz,Iran XVII European Workshop on String Theory 2011 Italy, Padua September 2011.

0|)()(|0),( xxTxxiGT

0))((2 0 xxxx

)()(2

)(

2

2log)(2)(

2)!1(!

)1(

2)(

111

11

0

2

1

iziNizJzK

z

zzJzN

z

ss

zzJ

s

ss

Feynman propagator

Two point function in Krein space

02

02

10

2

02

)2()(

8)(

8

1),(Re),(

m

mJmxxGxxG P

FT

0),(Relim,)(8

1

16),(Relim

000

2

0

xxG

mxxG P

FPF

The divergence appears in the imaginary part of this eq. and the real part is convergent :

21

021

0

1

0

1)(lim,

12)(lim,

2

1)(lim

zZ

zK

zz

zN

z

zJzzz

)(2

))(2()(

42

)2()2()(

8)(

8

1

)2(),(

02

02

102

2

02

02

102

10

2

022

).(

4

4

m

mKim

m

miNmJm

imk

ekdxxG

xxikPF

Page 10: By:Farrin Payandeh University of Payame Noor, Tabriz,Iran XVII European Workshop on String Theory 2011 Italy, Padua September 2011.

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Page 11: By:Farrin Payandeh University of Payame Noor, Tabriz,Iran XVII European Workshop on String Theory 2011 Italy, Padua September 2011.

Divergent Integrals of QED in Krein Space

2 2( )2 2 0

(1)is k m iids e

k m i

and using integral representation of the causal propagator in momentum space:

General form of divergent integrals of QED is:

we can see that the real part is convergent:

Page 12: By:Farrin Payandeh University of Payame Noor, Tabriz,Iran XVII European Workshop on String Theory 2011 Italy, Padua September 2011.

Convergent expressions of vacuum polarization and vertex graphs in krein space will be:

†0 0( , , ) ( , , ) ( , , )p pp q p p q p p q p

Page 13: By:Farrin Payandeh University of Payame Noor, Tabriz,Iran XVII European Workshop on String Theory 2011 Italy, Padua September 2011.

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Page 14: By:Farrin Payandeh University of Payame Noor, Tabriz,Iran XVII European Workshop on String Theory 2011 Italy, Padua September 2011.

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Page 15: By:Farrin Payandeh University of Payame Noor, Tabriz,Iran XVII European Workshop on String Theory 2011 Italy, Padua September 2011.

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Page 16: By:Farrin Payandeh University of Payame Noor, Tabriz,Iran XVII European Workshop on String Theory 2011 Italy, Padua September 2011.

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Page 17: By:Farrin Payandeh University of Payame Noor, Tabriz,Iran XVII European Workshop on String Theory 2011 Italy, Padua September 2011.

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Page 18: By:Farrin Payandeh University of Payame Noor, Tabriz,Iran XVII European Workshop on String Theory 2011 Italy, Padua September 2011.

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Page 19: By:Farrin Payandeh University of Payame Noor, Tabriz,Iran XVII European Workshop on String Theory 2011 Italy, Padua September 2011.

Quantum Field Theory with the N.F.S. , Quantum Field Theory with the N.F.S. , an answer to Feynman reply , “ A an answer to Feynman reply , “ A Nobel prize for sweeping the rushes Nobel prize for sweeping the rushes (infinties) under the rug” ?(infinties) under the rug” ?

Negative-energy modes as a candidate solution to some problems in quantum physics?

Page 20: By:Farrin Payandeh University of Payame Noor, Tabriz,Iran XVII European Workshop on String Theory 2011 Italy, Padua September 2011.

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Page 21: By:Farrin Payandeh University of Payame Noor, Tabriz,Iran XVII European Workshop on String Theory 2011 Italy, Padua September 2011.

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Page 22: By:Farrin Payandeh University of Payame Noor, Tabriz,Iran XVII European Workshop on String Theory 2011 Italy, Padua September 2011.

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Page 23: By:Farrin Payandeh University of Payame Noor, Tabriz,Iran XVII European Workshop on String Theory 2011 Italy, Padua September 2011.

2323

Case Study

P. A. M. Dirac: Bakerian Lecture , Proceedings of the Royal Society A (1941)

GHOSTBUSTING:Reviving quantumtheories that were thoughtto be dead

Page 24: By:Farrin Payandeh University of Payame Noor, Tabriz,Iran XVII European Workshop on String Theory 2011 Italy, Padua September 2011.

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Thank you for your

kind attention