Sample-efficient benchmarking of multi-photon interference on a boson sampler in the sparse regime

TL;DR

This paper introduces a maximum likelihood-based method to efficiently benchmark and monitor noise in boson sampling experiments, aiding the verification of quantum advantage in noisy, near-term quantum devices.

Contribution

It presents a novel sparse-sample approach for assessing noise levels and photon indistinguishability in boson samplers, enabling real-time diagnostics and validation of quantum advantage.

Findings

Method accurately detects noise levels in boson sampling

Sources of noise compound, affecting photon indistinguishability

Real-time noise monitoring is feasible with the proposed approach

Abstract

Verification of a quantum advantage in the presence of noise is a key open problem in the study of near-term quantum devices. In this work, we show how to assess the quality of photonic interference in a linear optical quantum device (boson sampler) by using a maximum likelihood method to measure the strength at which various noise sources are present in the experiment. This allows us to use a sparse set of samples to test whether a given boson sampling experiment meets known upper bounds on the level of noise permissible to demonstrate a quantum advantage. Furthermore, this method allows us monitor the evolution of noise in real time, creating a valuable diagnostic tool. Finally, we observe that sources of noise in the experiment compound, meaning that the observed value of the mutual photon indistinguishability, which is the main imperfection in our study, is an effective value taking into account all sources of error in the experiment.