Superpostions of time evolutions of a quantum system and a quantum time-translation machine

Yakir Aharonov, J. Anandan, Sandu Popescu +1 more

A method to obtain a superposition of time evolutions of a quantum system which correspond to different Hamiltonians as well as to different periods of time is derived. Its application to amplification of an effect due to the action of weak forces is considered. A quantum time-translation machine based on the same principle, utilizing the gravitational field, is also considered.

Dieter Suter, Matthias Ernst, Richard R. Ernst

We report for the first time an experimental realization of a ‘quantum time-translation machine’ via superpositions of time evolutions as suggested by Aharonov, Anandan, Popescu and Vaidman (1990, Phys. Rev. Lett., 64, 2965). The physical system consists of two coupled spins 1/2 and the amplification scheme is applied to the heteronuclear coupling between the two spins. We give a simple explanation of the phenomenon and suggest possible classical analogues.

Arno Böhm, Piotr Kielanowski, G. B. Mainland

Dieter Suter

A simple optical experiment is discussed that implements the ``quantum time-translation machine'' suggested by Aharonov et al. [Phys. Rev. Lett. 64, 2965 (1990)] for photons. The time-translation effect was observed experimentally as the shift of the fringe pattern in a modified Mach-Zehnder interferometer. The possibility of describing the effect classically, in terms of Maxwell's equations, suggests an alternative interpretation that does not invoke time-translation effects.