B'E'C'BoseEinstein Condensation

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B.E.C.(Bose-Einstein Condensation)

• ??? ???(98)

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Physics
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Quantum Physics
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Quantum Statistics
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Predicted 1924Created 1995
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The Nobel Prize in Physics 2001
USA(Eric A.Cornell,1961) Germany(Wolfgang
Kettlerle,1957) USA(Carl E.Wieman,1951)
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Spin Classification

• Fermions odd half integer spin
• Bosons integer spin
• It determines the nature of the energy
  distribution in a collection of the particles.

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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,
  ....

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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, ....

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Bose-Einstein Condensation

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

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Laser cooling and trapping

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

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Evaporative cooling

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

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Look like?
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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