B.E.C.(Bose-Einstein Condensation) 발표자 : 이수룡 (98)

Physics

Quantum Physics

Quantum Statistics

Predicted 1924… …Created 1995

The Nobel Prize in Physics 2001 USA(Eric A.Cornell,1961) Germany(Wolfgang Kettlerle,1957) USA(Carl E.Wieman,1951)

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

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,....

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, 4 He atoms, pions,....

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

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

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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References Physics 2000 Hyperphysics by Georgia State University The Nobel Prize in Physics e/frameless/fermibos.html de8.html de7.html