Optimal entanglement-assisted electromagnetic sensing and communication in the presence of noise

TL;DR

This paper introduces a novel receiver architecture that harnesses broadband TMSV states' quantum advantages in noisy, lossy environments, surpassing classical systems in sensing and communication tasks.

Contribution

The paper presents the correlation-to-displacement receiver, enabling optimal quantum performance with broadband TMSV states under realistic noise and loss conditions.

Findings

Achieves quantum optimal performance in noisy scenarios

Surpasses classical systems in sensing and communication

Robust against entanglement-breaking loss and noise

Abstract

High time-bandwidth product signal and idler pulses comprised of independent identically distributed two-mode squeezed vacuum (TMSV) states are readily produced by spontaneous parametric downconversion. These pulses are virtually unique among entangled states in that they offer quantum performance advantages -- over their best classical-state competitors -- in scenarios whose loss and noise break their initial entanglement. Broadband TMSV states' quantum advantage derives from its signal and idler having a strongly nonclassical phase-sensitive cross correlation, which leads to information bearing signatures in lossy, noisy scenarios stronger than what can be obtained from classical-state systems of the same transmitted energy. Previous broadband TMSV receiver architectures focused on converting phase-sensitive cross correlation into phase-insensitive cross correlation, which can be measured in second-order interference. In general, however, these receivers fail to deliver broadband TMSV states' full quantum advantage, even if they are implemented with ideal equipment. This paper introduces the correlation-to-displacement receiver -- a new architecture comprised of a correlation-to-displacement converter, a programmable mode selector, and a coherent-state information extractor -- that can be configured to achieve quantum optimal performance in known sensing and communication protocols for which broadband TMSV provides quantum advantage that is robust against entanglement-breaking loss and noise.