Quantum phase communication channels assisted by non-deterministic noiseless amplifiers

TL;DR

This paper investigates how probabilistic noiseless linear amplifiers can improve quantum phase communication channels affected by phase diffusion, especially for weak signals, by analyzing their performance with different noise models and receivers.

Contribution

It demonstrates the effectiveness of NLA in enhancing quantum communication channel capacity under phase diffusion, considering both static and dynamical noise effects.

Findings

NLA improves channel performance for weak signals.

NLA's effectiveness depends on noise type and receiver design.

Memory effects influence the capacity enhancement by NLA.

Abstract

We address quantum $M$-ary phase-shift keyed (PSK) communication channels in the presence of phase diffusion, and analyze the use of probabilistic noiseless linear amplifiers (NLA) to enhance performance of coherent signals. We consider both static and dynamical phase diffusion and assess the performances of the channel for ideal and realistic phase receivers. Our results show that NLA employed at the stage of signal preparations is a useful resource, especially in the regime of weak signals. We also discuss the interplay between the use of NLA, and the memory effects occurring with dynamical noise, in determining the capacity of the channel.