‘Arrow of time’ reversed in quantum experiment

Mario Castagnino, Manuel Gadella, Olímpia Lombardi

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.

H. Dieter Zeh

Daniel P. Sheehan

The thermodynamic arrow of time is directed by the second law of thermodynamics. In the last ten years, over two dozen theoretical challenges to the second law, many of them laboratory testable, have cast serious doubt on the law’s continued universality. In this paper we review a representative challenge and consider the possibility that the thermodynamic arrow might be reversed on local or global scales. Experiments are proposed to test the connections between retrocausation and a reversed thermodynamic arrow.

H. D. Zeh

J. G. Cramer

Agendanken experiment is proposed for distinguishing between two models accounting for the macroscopic arrow of time. The experiment involves the veloeity revesal of components of an isolated system, and the two models give contrasting predictions as to its behavior.