V. Capek, FROM CONVOLUTIONLESS GENERALIZED MASTER TO FINITE-COUPLING PAULI MASTER-EQUATIONS, Czechoslovak journal of Physics, 48(9), 1998, pp. 993-1012
Time-convolutionless Generalized Master Equations (TCL-GME) for probab
ilities of finding a system in a general state, irrespective of the st
ate of the thermodynamic bath, are investigated. For general systems i
nteracting with a genuine bath with a continuous spectrum described by
time-independent system + bath Hamiltonians and after the thermodynam
ic limit for the bath, the long-time asymptotics of time-dependent coe
fficients can be taken as counterparts of Pauli-Master-Equation (PME)
transfer rates. Here, within TCL-GME, asymptotics of these coefficient
s is calculated without resorting to any approximation. In the lowest
order, these coefficients are known to turn to the usual Fermi Golden
Rule transfer rates. Anyway, we argue that if the exact form of these
coefficients has a long-time limit, this limit is inevitably equal to
zero. This makes the possibility to derive standard markovian finite-c
oupling Pauli, rate or balance equations as long-time asymptotics to T
CL-GME illusory.