Quantum Langevin Dynamics of a Two State System Coupled to a Bosonic Bath. II
Toshio Tsuzuki · Progress of Theoretical Physics Supplement · 1989
The quantum Langevin equation of a two-state system coupled to a bosonic bath is studied on the basis of the bare boson representation. We can realize the role of the reaction field more explicitly in this case than in the case of displaced boson representation studied in I. The characteristic frequency of variable which mediates the interaction between the slow variable of the two-state system and the bath is determined quantum-mechanically by the commutation relation whose non-commutability is governed by the reaction field.