‘‘Weak measurements’’ and the ‘‘quantum time-translation machine’’ in a classical system

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.