Bose Einstein Condensation Condensed Matter II –Spring 2007


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Bose Einstein Condensation

  • Condensed Matter II –Spring 2007

  • Davi Ortega


Summary



Statistics of Idea Gas

  • Two Particles Gas: A and B.



Some Theory



More Theory



Two more useful results



An Last statement

  • This whole theory assume non interacting particles: Schrödinger Equation

  • Interacting Particles: Gross-Pitaeviski Eq.



Achievements

  • 1938 – Pyotr Kapitsa John Allen and Don Misener: Helium 4

  • 1995 – Eric Cornell and Carl Wieman: Rb87: Pure BEC.

  • 1995 – Wolfgang Ketterle Na23. (4 months later)



Liquid He vs. Diluted Gas

  • Strong Interactions in He qualitatively changes the nature of transition.

  • Diluted Gas

  • Liquid Helium

    • Zero Viscosity
    • And other strange properties.


How to make a BEC ?

  • Heat the atoms: 600 K (gas)

  • Confine them in a beam

  • Decelerate the beam

  • Trap the atoms (Magneto Optical Trap)

  • Magnetic Trapping (avoid atoms recoil by spontaneous emission and random absorption)

  • Evaporative Cooling



Famous Picture



Any other way ?!



Current Research

  • BEC achieved in several atoms.

  • Strange Properties:

  • Wave-like phenomena in atoms.

    • Interference between two condensates.
  • Atom Laser




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