Mitigating scattering in a quantum system using only an integrating sphere

TL;DR

This paper demonstrates an experimental method using an integrating sphere to recover quantum correlations in a two-mode squeezed light system significantly affected by scattering, achieving nearly half of the original mutual information despite high photon loss.

Contribution

It introduces a novel scheme employing an integrating sphere to mitigate scattering effects in quantum systems, enhancing quantum correlation recovery.

Findings

Recovered 47.5% of mutual information despite >85% photon loss

Demonstrated effective mitigation of scattering in quantum correlations

Pioneering approach for practical quantum information applications

Abstract

Strong quantum-correlated sources are essential but delicate resources for quantum information science and engineering protocols. Decoherence and loss are the two main disruptive processes that lead to the loss of nonclassical behavior in quantum correlations. In quantum systems, scattering can contribute to both decoherence and loss. In this work, we present an experimental scheme capable of significantly mitigating the adverse impact of scattering in quantum systems. Our quantum system is composed of a two-mode squeezed light generated with the four-wave mixing process in hot rubidium vapor, and a scatterer is introduced to one of the two modes. An integrating sphere is then placed after the scatterer to recollect the scattered photons. We use mutual information between the two modes as the measure of quantum correlations, and demonstrate a 47.5% mutual information recovery from scattering, despite an enormous photon loss of greater than 85%. Our scheme is a pioneering step towards recovering quantum correlations from disruptive random processes, thus has the potential to bridge the gap between proof-of-principle demonstrations and practical real-world deployments of quantum protocols.