Semi-device independent characterization of multiphoton indistinguishability

TL;DR

This paper introduces robust semi-device independent methods for characterizing multiphoton indistinguishability using bunching and photon number variance measurements, applicable to scalable photonic systems.

Contribution

It presents novel certification techniques that remain effective despite experimental errors and misconfigured interferometers in large-scale photonic devices.

Findings

Methods effectively certify multiphoton indistinguishability in complex systems.

Demonstrated robustness against interferometer misalignments.

Applicable to scalable photonic platforms with quantum-dot sources.

Abstract

Multiphoton indistinguishability is a central resource for quantum enhancement in sensing and computation. Developing and certifying large scale photonic devices requires reliable and accurate characterization of this resource, preferably using methods that are robust against experimental errors. Here, we propose a set of methods for the characterization of multiphoton indistinguishability, based on measurements of bunching and photon number variance. Our methods are robust in a semi-device independent way, in the sense of being effective even when the interferometers are incorrectly dialled. We demonstrate the effectiveness of this approach using an advanced photonic platform comprising a quantum-dot single-photon source and a universal fully-programmable integrated photonic processor. Our results show the practical usefulness of our methods, providing robust certification tools that can be scaled up to larger systems.