1. Space Telescope Science Institute
Title
“When freezing cold is not cold enough - new forms of matter close to absolute zero temperature”
Wolfgang Ketterle
Massachusetts Institute of Technology MIT-Harvard Center for Ultracold Atoms
9/2/09 Meridian Lecture
Space Telescope Science Institute
Baltimore

2. The coldest matter in the universe
What is energy
Quantum Gases
The coldest matter in the universe

3. One form of energy is motion (kinetic energy).
What is temperature
What is temperature?
A measure of energy
One form of energy is motion (kinetic energy).

4. Cold particles move slowly
Hot particles are fast

5. What is the lowest temperatures possible?

6. What is temperature
Zero degree Kelvin (-273 degrees Celsius, degrees Fahrenheit) is the zero point for energy

7. The highest temperature is infinite
(In principle it is possible for particles to have arbitrarily high kinetic energies – until they become so heavy (due to E=mc2) that they from a black hole – at the Planck temperature of 1032 K)

8. What is the difference in temperature between summer and winter?
What is temperature
What is the difference in temperature between summer and winter?
20 %

9. How cold is interstellar space?
3 K

10. What happens to atoms at low temperatures?
Atom slow down
What happens to atoms at low temperatures?
They slow down
600 mph (300 m/sec)
1 cm/sec
They march in lockstep

11. Molecule of the year
Matter made of waves!

12. Molecule of the year

13. Laser beam and light bulb
Photons/atoms moving randomly
Photons/atoms are one big wave
Ordinary light
Laser light

14. Bose/Einstein
* 1925

15. The concepts
The cooling methods
Laser cooling
Evaporative cooling

16. Hot atoms

17. Hot atoms
Laser beams

18. Hot atoms
Fluorescence
Laser beams

19. If the emitted radiation is blue shifted
Fluorescence
Laser beams
If the emitted radiation is blue shifted
(e.g. by the Doppler effect) ….

20. Cold atoms: 10 – 100 K Fluorescence Laser beams
Chu, Cohen-Tannoudji, Phillips, Pritchard, Ashkin, Lethokov, Hänsch, Schawlow, Wineland …

21. MOT
Laser cooling
2.5 cm

23. The concepts
Evaporative cooling

24. Magnetic trap setup (GIF)
Phillips et al. (1985)
Pritchard et al. (1987)

25. Magnetic trap setup The condensate a puff of gas
100,000 thinner than air
size comparable to the
thickness of a hair
magnetically suspended in an ultrahigh vacuum chamber

26. Guinness Book Record

27. WK and Dark SPOT
Sodium laser cooling experiment (1992)

28. Sodium BEC I experiment (2001)

29. Evaporative cooling
Dan Kleppner
Tom Greytak
Dave Pritchard

30. Current Research
Cold molecules
Cold fermions

31. Can electrons form a Bose-Einstein condensate and become superfluid (superconducting)?
Two kinds of particles
Bosons: Particles with an even number of protons, neutrons and electrons
Fermions: odd number of constituents
Only bosons can Bose-Einstein condense!

33. Can electrons form a Bose-Einstein condensate and become superfluid (superconducting)?
Two kinds of particles
Bosons: Particles with an even number of protons, neutrons and electrons
Fermions: odd number of constituents
Only bosons can Bose-Einstein condense!
How can electrons (fermions) condense?
They have to form pairs!

34. Can we learn something about superconductivity of electrons from cold atoms?
Yes, by studying pairing and superfluidity of atoms with an odd number of protons, electrons and neutrons

35. Gallery of superfluid gases
Atomic Bose-Einstein condensate (sodium)
Molecular Bose-Einstein condensate (lithium 6Li2)
Pairs of fermionic atoms (lithium-6)