On Entanglement Assisted Classical Optical Communications

Ivan B Djordjevic

doi:10.1109/access.2021.3066237

Abstract

Entanglement assisted communication is advocated by numerous authors as an alternative to classical communication offering significant improvement in channel capacity, in particular in noisy regime. In all those papers it is always assumed that entanglement can be distributed without any imperfections, except for attenuation. We demonstrate that under imperfect pre-shared entanglement distribution, assuming that entanglement distribution channel is modeled as a noisy and lossy Bosonic channel, the entanglement assisted communication can be inferior compared to the classical communication, depending on the parameters of the distribution channel. We identify the conditions under which entanglement assistance can still provide an advantage over the classical case. In particular, when both communication and entanglement distribution channels are not used for entanglement assisted communication but rather for classical transmission instead then the classical capacity is always higher than the entanglement assisted capacity. We also study the entanglement assisted communication under the strong atmospheric turbulence effects.

Highlights

Quantum information processing (QIP) opens new opportunities for high-precision sensing, secure communications, and ultra-high-performance computing [1]–[3]
The entanglement assisted (EA) classical capacity, that is the maximum of quantum mutual information [4], has been known for decades [4]–[6]; The associate editor coordinating the review of this manuscript and approving it for publication was Barbara Masini
In this paper we study EA channel capacity assuming that the entanglement distribution is imperfect, subject to attenuation and noise, and compare it against classical channel capacity for homodyne and heterodyne detections

Summary

INTRODUCTION

Quantum information processing (QIP) opens new opportunities for high-precision sensing, secure communications, and ultra-high-performance computing [1]–[3]. The pre-shared entanglement can be used, at least in theory, to improve the classical communication capacity [4]–[8]. To distribute the entangled signal-idler photon pairs either the satellite-toground links or fiber-based quantum network, as illustrated, can be used. In this paper we study EA channel capacity assuming that the entanglement distribution is imperfect, subject to attenuation and noise, and compare it against classical channel capacity for homodyne and heterodyne detections. We demonstrate that in the presence of imperfect pre-shared entanglement, EA assisted capacity get reduced significantly and when signal-idler photon pairs get distributed over the same noisy channel, used for data transmission, EA assisted.

REALISTIC ENTANGLEMENT ASSISTED CLASSICAL OPTICAL COMMUNICATION SYSTEMS

ENTANGLEMENT ASSISTED COMMUNICATION OVER FSO LINKS

CONCLUDING REMARKS