A generating-function approach to the interference of squeezed states with partial distinguishability

TL;DR

This paper introduces a generating-function framework using phase-space formalism to analyze how partial distinguishability affects the interference of squeezed states, providing insights into noise in quantum photonic systems.

Contribution

It develops a novel phase-space based method to model multiphoton interference with partial distinguishability, surpassing traditional noninterfering mode models.

Findings

Captures genuine multiphoton interference effects due to internal state overlap.

Provides a physical understanding of distinguishability-induced noise in Gaussian boson sampling.

Enables systematic analysis of phase effects from internal state overlap.

Abstract

Photon distinguishability is a fundamental property manifested in multiphoton interference and one of the main sources of noise in any photonic quantum information processing. In this work, rather than relying on first-quantization methods, we build on a generating-function framework based on the phase-space formalism to characterize the effects of partial distinguishability on the interference of single-mode squeezed states. Our approach goes beyond commonly used models that represent distinguishability via additional noninterfering modes and captures genuine multiphoton interference effects induced by the overlap of the internal state of the photons. This description provides a clear physical account of how distinguishability gives rise to effective noise in Gaussian boson sampling protocols while enabling a systematic investigation of phase effects arising from the overlap of the internal states.