Squeezing-enhanced phase-shift-keyed binary communication in noisy channels

TL;DR

This paper demonstrates that squeezing enhances binary phase-shift-keyed communication in noisy channels by improving state discrimination, with homodyne detection reaching optimal performance under large noise, even with seed signal noise.

Contribution

It proves squeezing improves discrimination in Gaussian state channels and shows homodyne detection's optimality in high noise conditions, including realistic seed noise scenarios.

Findings

Squeezing improves state discrimination at fixed energy.

Homodyne detection achieves quantum limit in large noise regimes.

Squeezing benefits persist even with seed signal noise.

Abstract

We address binary phase-shift-keyed communication channels based on Gaussian states and prove that squeezing improves state discrimination at fixed energy of the channel, also in the presence of phase diffusion. We then assess performances of homodyne detection against the ultimate quantum limits to discrimination, and show that homodyning achieves optimality in large noise regime. Finally, we consider noise in the preparation of the seed signal (before phase encoding) and show that also in this case squeezing may improve state discrimination in realistic conditions.