Quantum Interference of Distinguishable Photons Based on Spatially-Resolved Measurements

TL;DR

This paper demonstrates quantum interference between distinguishable photons using spatially-resolved measurements, revealing interference effects that are hidden in non-spatially resolved approaches, supported by experimental and theoretical agreement.

Contribution

It introduces a novel experimental method to observe quantum interference of distinguishable photons via spatially-resolved measurements, highlighting the importance of spatial resolution.

Findings

Quantum interference observed with distinguishable photons in spatially-resolved measurements

Interference effects are washed out in non-spatially resolved measurements

Experimental results align with theoretical predictions

Abstract

We present experimental results demonstrating the quantum interference of two photons distinguishable in their transverse momenta, each entering the input ports of a balanced beam splitter. This counterintuitive interference effect is made possible through spatially resolved measurements in the near field, i.e., by resolving the conjugate variable in which the photons are distinguishable. Our experimental findings agree with theoretical predictions. We contrast our results with a non-spatially resolved measurement where averaging over the photons' positions washes out the quantum interference observed in spatially resolved measurements.