Quantum phase communication channels in the presence of static and dynamical phase diffusion

TL;DR

This paper investigates quantum phase communication channels affected by static and dynamical phase diffusion, evaluating their robustness and mutual information performance under various noise conditions and receiver types.

Contribution

It provides a detailed analysis of phase diffusion effects on quantum communication channels, comparing ideal and covariant phase-space-based receivers, and exploring non-Markovian noise impacts.

Findings

Channels are robust against phase noise, especially with large alphabets and low energy.

Mutual information is preserved by environmental time correlations in non-Markovian noise.

Revivals of mutual information occur when noise spectra are detuned from the information carrier.

Abstract

We address quantum communication channels based on phase modulation of coherent states and analyze in details the effects of static and dynamical (stochastic) phase diffusion. We evaluate mutual information for an ideal phase receiver and for a covariant phase-space-based receiver, and compare their performances by varying the number of symbols in the alphabet and/or the overall energy of the channel. Our results show that phase communication channels are generally robust against phase noise, especially for large alphabets in the low energy regime. In the presence of dynamical (non-Markovian) noise the mutual information is preserved by the time correlation of the environment, and when the noise spectra is detuned with respect to the information carrier, revivals of mutual information appears.