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B'E'C'BoseEinstein Condensation

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Enrico Fermi, Paul A.M. Dirac described the special properties of this type of particles. Fermi-Dirac statistics, Pauli exclusion principle ... – PowerPoint PPT presentation

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Title: B'E'C'BoseEinstein Condensation


1
B.E.C.(Bose-Einstein Condensation)
  • ??? ???(98)

2
Physics
3
Quantum Physics
4
Quantum Statistics
5
Predicted 1924Created 1995
6
The Nobel Prize in Physics 2001
USA(Eric A.Cornell,1961) Germany(Wolfgang
Kettlerle,1957) USA(Carl E.Wieman,1951)
7
Spin Classification
  • Fermions odd half integer spin
  • Bosons integer spin
  • It determines the nature of the energy
    distribution in a collection of the particles.

8
Fermions
  • Enrico Fermi, Paul A.M. Dirac described the
    special properties of this type of particles.
  • Fermi-Dirac statistics, Pauli exclusion principle
  • no two identical fermions can be in exactly the
    same quantum state
  • electrons, protons, neutrons, muons, quarks,
    ....

9
Bosons
  • In 1924 Bose made an important theory regarding
    light particles. Einstein extended it.
  • Bose-Einstein statistics
  • an unlimited number of identical bosons in
    exactly the same state
  • photons, 4He atoms, pions, ....

10
Bose-Einstein Condensation
  • From Bose-Einstein Condensation
  • A phase transition at low enough temperatures
  • Bose did not find it.

11
Laser cooling and trapping
  • Laser beams slow down atoms by the Doppler shift.
  • Then trapping
  • This is called optical molasses.
  • To 10-4 K

12
Evaporative cooling
  • Magnetic trapping
  • To 10-6 K
  • The particle having the high energy escapes from
    the magnetic trap.
  • The total temperature is decreased.

13
Look like?
14
References
  • Physics 2000
  • Hyperphysics by Georgia State University
  • The Nobel Prize in Physics 2001
  • http//press.web.cern.ch/pdg/particleadventure/fra
    meless/fermibos.html
  • http//musr.physics.ubc.ca/jess/p200/spin/node8.h
    tml
  • http//musr.physics.ubc.ca/jess/p200/spin/node7.h
    tml
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