Quantum Illumination with Gaussian States

TL;DR

This paper demonstrates that quantum illumination using Gaussian states and optimal joint measurement significantly outperforms classical coherent-state systems in detecting low-reflectivity objects in noisy environments, achieving a 6 dB error probability advantage.

Contribution

It introduces a quantum illumination protocol with Gaussian states that attains a 6 dB error probability advantage over classical methods without requiring entanglement during detection.

Findings

Quantum illumination achieves a 6 dB advantage in error probability exponent.

The advantage persists despite the absence of entanglement during measurement.

Optimal joint measurement on signal and idler beams enhances detection performance.

Abstract

An optical transmitter irradiates a target region containing a bright thermal-noise bath in which a low-reflectivity object might be embedded. The light received from this region is used to decide whether the object is present or absent. The performance achieved using a coherent-state transmitter is compared with that of a quantum illumination transmitter, i.e., one that employs the signal beam obtained from spontaneous parametric downconversion (SPDC). By making the optimum joint measurement on the light received from the target region together with the retained SPDC idler beam, the quantum illumination system realizes a 6 dB advantage in error probability exponent over the optimum reception coherent-state system. This advantage accrues despite there being no entanglement between the light collected from the target region and the retained idler beam.