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