Abstract

Making a position measurement to determine which way a particle goes through a double slit apparatus necessarily destroys the interference pattern. In well known welcher Weg experiments, such as Einstein’s recoiling slit, the destruction of interference can be explained by a classical random momentum transfer, described by a convolution of the momentum probability distribution with a momentum-kick probability distribution. It is possible, however, to construct welcher Weg schemes (eg that of Scully et al. [1]) in which the fundamental quantum description in terms of momentum transfer probability amplitudes cannot be expressed classically [2].

© 1996 Optical Society of America