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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.
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B.E.C.(Bose-Einstein Condensation) 발표자: 이수룡(98)
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 energydistribution 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 exclusionprinciple • 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, 4He 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.
References • Physics 2000 • Hyperphysics by Georgia State University • The Nobel Prize in Physics 2001 • http://press.web.cern.ch/pdg/particleadventure/frameless/fermibos.html • http://musr.physics.ubc.ca/~jess/p200/spin/node8.html • http://musr.physics.ubc.ca/~jess/p200/spin/node7.html