The time reversal operator for semigroup evolutions

Robert C. Bishop

Naomichi Hatano, Gonzalo E. Ordonez

Andrzej Posiewnik

Arno Böhm

The division of a scattering experiment into the preparation of a state and the registration of an observable in this state defines an obvious but commonly ignored quantum-mechanical arrow of time. This leads to irreversibility on the microphysical level. The time evolution semigroup for exponentially decaying Gamow states is an example of this microphysical irreversibility. A time-reversal operator exists which is compatible with the quantum-mechanical arrow of time.

Mario Castagnino, Manuel Gadella, Olímpia Lombardi

The aim of this paper is to analyze the concepts of time-reversal invariance and irreversibility in the so-called ’time-asymmetric quan-tum mechanics’. We begin with pointing out the difference between these two concepts. On this basis, we show that irreversibility is not as tightly linked to the semigroup evolution laws of the theory-which lead to its non time-reversal invariance- as usually suggested. In turn, we argue that the irreversible evolutions described by the theory are coarse-grained processes. 1 1

E. B. Davies