Symmetry Allows for Distinguishability in Totally Destructive Many-Particle Interference

We investigate, in a four-photon interference experiment in a laser-written waveguide structure, how symmetries control the suppression of many-body output events of a J(x) unitary. We show that totally destructive interference does not require mutual indistinguishability between all but only between symmetrically paired particles, in agreement with recent theoretical predictions. The outcome of the experiment is well described by a quantitative simulation that accounts for higher-order emission of the photon source, imbalances in the scattering network, partial distinguishability, and photon loss.

Automated summary

The study investigates how symmetries control the suppression of many-body output events in a four-photon interference experiment. It is found that totally destructive interference only requires mutual indistinguishability between symmetrically paired particles. The experiment's outcome aligns well with a quantitative simulation that considers higher-order emission of the photon source, imbalances in the scattering network, partial distinguishability, and photon loss.