Demonstration of Coherent State Discrimination Using a Displacement Controlled Photon Number Resolving Detector

TL;DR

This paper presents an experimental demonstration of a novel measurement scheme combining displacement operations with photon number resolving detectors, outperforming traditional homodyne detection in coherent state discrimination and quantum key distribution.

Contribution

The work introduces a displacement-controlled photon number resolving detector that surpasses Gaussian-based methods in state discrimination and quantum communication tasks.

Findings

Outperforms homodyne detection in coherent state discrimination

Proves optimality of Gaussian operations within all Gaussian strategies

Enhances continuous variable quantum key distribution security

Abstract

We experimentally demonstrate a new measurement scheme for the discrimination of two coherent states. The measurement scheme is based on a displacement operation followed by a photon number resolving detector, and we show that it outperforms the standard homodyne detector which we, in addition, proof to be optimal within all Gaussian operations including conditional dynamics. We also show that the non-Gaussian detector is superior to the homodyne detector in a continuous variable quantum key distribution scheme.