国家重点实验室 BEC o For N=2, C(w,0)=1-e=0.5 u C(W,0)=(1-e)2=0.25 y2 C(W,2)=2(1-e)-(1-e)2=0.75 W. 23 BEC For N=2, 23 ( ) 1 1 C W( ) 1 0.5 =− = ε ( ) 1 2 2 C W( ) (1 ) 0.25 =− = ε ( ) 2 2 2 C W( ) 2(1 ) (1 ) 0.75 = − −− = ε ε W2 1 u W u2 W 1 y 2 y 1 x 2 x