1. Bose-Einstein Condensation (a tutorial) Melinda Kellogg Wyatt Technology Corporation Santa Barbara, CA June 8, 2010

2. Satyendra Bose (1894 – 1974)

3. FermionsBosons

4. Spin

5. Elementary particles also spin… electron: spin ½ proton/neutron: spin ½ quark: spin ½ photon: spin 1 graviton: spin 2 Higgs boson: spin 0

6. half-integral spin: electrons, protons, neutrons… zero or integral spin: Higgs bosons, photons, helium-4 atoms, sodium-23, rubidium-87 atoms… FermionsBosons obey Pauli exclusion principle don’t obey Pauli exclusion principle

7. Albert Einstein (1879 – 1955)

8. e - e - e - e - e - e - e - e - Bose-Einstein Condensate

9. where: Critical Temperature

10. First Bose-Einstein Condensate (BEC): Superfluid He-4

11. a better BEC requires weaker interatomic interactions… a diffuse gas

12. Laser Cooling

13. stationary atom absorbs green photon

14. and shortly thereafter re-emits it

17. slightly detune laser towards the red…

18. photon passes through, unless…

19. photon is Doppler shifted appears green to atom atom is moving toward light source,

24. laser

25. Laser (Doppler) Cooling cools to ~ 150 μK

26. Evaporative Cooling

27. Magnetic Trap

28. low field seeking high field seeking Magnetic Potential Energy S N  

29. Magnetic Trap

30. Evaporative Cooling magnetic field strength position

31. Evaporative Cooling potential energy position

32. Evaporative Cooling position E magnetic field strength

33. Evaporative Cooling position E magnetic field strength

34. Evaporative Cooling position E magnetic field strength

35. Evaporative Cooling position magnetic field strength

36. Evaporative Cooling position  B  ~ 30 MHz magnetic field strength

37. Evaporative Cooling position magnetic field strength

38. Evaporative Cooling position E magnetic field strength

39. Evaporative Cooling cools to < 1 μK

40. BEC of Sodium Atoms Durfee & Ketterle, Optics Express 2, 299 (1998)

41. Thank you! (mainly of excitons)