Chapter5_4

# Chapter5_4 - PHY4604 R D Field Bosons and Fermions in a Box...

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PHY4604 R. D. Field Department of Physics Chapter5_4.doc University of Florida Two Fermion Ground State Probability Density 00 . 51 x 2 /L x 1 = 0.5 L Fermi-Dirac Bosons and Fermions in a Box Two Particles in a Box: For the problem of two particles in a one dimensional box (0 L) we have ) 2 /( ) ( 2 2 2 2 2 mL E β α π αβ + = h and () ) / ( sin ) / ( sin ) / ( sin ) / ( sin 2 ) , ( 2 2 1 2 2 2 1 2 2 2 1 L x L x L x L x L x x classical απ βπ ρ + = ) / sin( ) / sin( ) / sin( ) / sin( 4 ) , ( 2 2 1 1 2 2 1 int L x L x L x L x L x x = Note that 1 ) , ( 2 1 2 1 = ∫∫ LL classical dx dx x x and δ = dx dx x x 2 1 2 1 int ) , ( . Ground State for Two Fermions: The lowest energy state for two fermions is α = 1 and β = 2 (or α = 2 and β = 1 ) and FD E mL E 0 2 2 2 12 ) 2 /( 5 = = h and ) / ( sin ) / 2 ( sin ) / 2 ( sin ) / ( sin 2 ) , ( 2 2 1 2 2 2 1 2 2 2 1 12 L x L x L x L x L x x classical + = ) / 2 sin( ) / sin( ) / 2 sin( ) / sin( 4 ) , ( 2 2 1 1 2 2 1 int 12 L x L x L x L x L x x = ) , ( ) , ( ) , ( 2 1 int 12 2 1 12 2 1 12 x x x x x x classical FD = . Put one particle at x 1 = 0.5L and plot the probability of finding the other particle at x 2 : ) / 2 ( sin 2 ) , 5 . 0 ( 2 2 2 2 1 12 L x L x L x FD = = . Ground State for Two Bosons:
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## This note was uploaded on 05/29/2011 for the course PHY 4064 taught by Professor Fields during the Spring '07 term at University of Florida.

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