Post on 23-Mar-2016
description
Ultracold Physics: Creating Quantum Matter at the Coldest Temperaturesin the Universe
Brian DeMarcoUniversity of Illinois
0 K
supernova core100,000,000,000 K
lava1,200 K
ice273 K
Room temperature294 K
dry ice164 K
liquid nitrogen77 K
liquid He4 K dilution refrigerator
0.003 K
Universe2.7 K
triple point cell273.16 K
“absolute zero”
surface of sun
6,000 K
Temperature Scale
lowest measured temperature
We cool to Absolute Zero, as far as we can tell
Cooling Below mK
0.000000000450 K200 mm/sec
1980s-90s: Developed techniques to cool atom gases to ultra-cold temperatures
Practical Applications
Atomic clocks
Atom gyroscopes
Atom gradiometers
Quantum MechanicsEverything is a quantum wave
𝜆=h /𝑚𝑣h=6.6×10− 34 𝐽 ⋅ 𝑠
Planck’s constant
Many-Particle Quantum MechanicsEverything is a quantum wave
Classical Matter
Quantum Matter
Many-Particle Quantum Mechanics
The waves overlap!
Matter Wave Interference
Quantum degeneracy2dB
B
hmk T
3 n
Many-Particle Quantum Mechanics
Quantum degeneracy
We don’t understand strongly-interacting many-particle quantum matter
The Route to Ultra-Cold•Laser cooling and trapping•Magnetic trapping and evaporative cooling
Our insulation: ultra-high vacuum (10-12 torr)
collection cellscience cell
10 mK 109 atoms
Laser Cooling
<100 nK 105 atoms
Evaporative Cooling
Data From Imaging
Quantum Particles
Bosons FermionsWaves overlap as much as possible
photons, W & Z bosons, 87RbWaves cannot overlapelectrons, protons,40K
Bosons Fermions
Bose-Einstein condensation Superfluidity
Quantum Degenerate Matter