Erasing Quantum Distinguishability via Single-Mode Filtering

TL;DR

This paper presents a linear optical method using single-mode filtering to erase quantum distinguishability, enhancing photon indistinguishability for quantum information applications, validated by experiments matching theoretical predictions.

Contribution

The authors introduce a practical linear optical technique to improve quantum indistinguishability, supported by a comprehensive quantum-multimode theory and experimental validation.

Findings

Significant increase in photon indistinguishability demonstrated

Excellent agreement between experiment and theory achieved

Method applicable to optical quantum information systems

Abstract

Erasing quantum-mechanical distinguishability is of fundamental interest and also of practical importance, particularly in subject areas related to quantum information processing. We demonstrate a method applicable to optical systems in which single-mode filtering is used with only linear optical instruments to achieve quantum indistinguishability. Through "heralded" Hong-Ou-Mandel interference experiments we measure and quantify the improvement of indistinguishability between single photons generated via spontaneous four-wave mixing in optical fibers. The experimental results are in excellent agreement with predictions of a quantum-multimode theory we develop for such systems, without the need for any fitting parameter.