Quantum communication with photon-number entangled states and realistic photodetection

TL;DR

This paper investigates how realistic photodetection imperfections affect quantum communication channels using photon-number entangled states, finding twin-beam states are more noise-robust than two-mode coherent states.

Contribution

It provides an analysis of the impact of non-ideal photodetection on quantum communication, comparing Gaussian and non-Gaussian states and optimizing channel capacity.

Findings

TWB-based channels are more robust against noise than TMC-based channels.

Robustness of TWB channels is nearly independent of dark count statistics.

Optimized bit discrimination thresholds improve channel capacity.

Abstract

We address the effects of realistic photodetection, with nonunit quantum efficiency and background noise (dark counts), on the performances of quantum communication schemes based on photon-number entangled states. We consider channels based on Gaussian twin-beam states and non-Gaussian two-mode coherent states and evaluate the channel capacity by optimizing the bit discrimination threshold. We found that TWB-based channels are more robust against noise than TMC-based ones and that this result is almost independent on the statistics of dark counts.