模型的普适性 In the weak coupling limit, any heat bath could be universal modeled as a collection of harmonic oscillators with the linear couplings to the surrounded system accordingly A.O. Caldiera, A.J. Leggett, Ann. Phys.(NY)149, 374(1983) M-level system H, =2 Inn (g, a*+Hc ) E E,(K)+ ∑ EK 力g/(纵 ITP模型的普适性 A. O. Caldiera , A. J. Leggett, Ann. Phys. (NY) 149, 374(1983). In the weak coupling limit, any heat bath could be universally modeled as a collection of harmonic oscillators with the linear couplings to the surrounded system accordingly. | |( H.c.), , =   + + H  n n n g j a j n M-level system I  ( ) ( ) j j N j E n nj  n  n  = = + 1 ,{ } ( ) 2 n n n   =  −   j |gj | 2 /4j