Mach-Zehnder interferometer for a two-photon wave packet - art. no. 023801

We propose an experiment that permits observation of the de Broglie two-pho ton wave packet behavior for a pair of photons, using a Mach-Zehnder interf erometer. It is based on the use of pulsed lasers to generate pairs of phot ons via spontaneous parametric down-conversion and the post-selection of ev ents. It differs from previous realizations by the use of a third time-corr elated photon to engineer the state of the photons. The same technique can give us which-path information via on "interaction-free" experiment and can be used in other experiments on the foundations of quantum mechanics relat ed to wave-particle duality and to nonlocality.