Probing the path information hidden in the quantum fluctuations of interference patterns

Abstract

It is commonly assumed that interference patterns contain no information about the path taken by the individual photons. Surprisingly, recent results based on the analysis of weak interactions with probe qubits suggest that this may be a misconception. Here we show that the fluctuations of detection events in quantum interference patterns are correlated with the fluctuations of particle presence in the paths. It is pointed out that this correlation is a general feature of quantum fluctuations that distinguishes them from classical noise.