Decoherence in Quantum Environment at Finite Temperature

抄録

Quantum mechanical decoherence process is studied with the use of a boson detector model. Generalizing the previous method, thermal effect is taken into account: Coherence of an incident particle is destroyed in interaction with its surroundings at finite temperature. Vanishing of off-diagonal elements of a reduced density matrix is rigorously shown when the detector (surroundings) is composed of a large number of constituents and/or its temperature is very high. The temperature effect reveals itself through a renormalization of interaction strength between an incident particle and the detector. Time evolution of the von Neumann entropy is explicitly determined.