Repeater-enhanced distributed quantum sensing based on continuous-variable multipartite entanglement

TL;DR

This paper proposes using noiseless linear amplifiers as quantum repeaters to mitigate entanglement loss in distributed quantum sensing, enabling enhanced measurement sensitivity beyond local resources with feasible technology.

Contribution

It introduces a practical NLA-based quantum repeater scheme for distributed sensing, overcoming entanglement-distribution loss and surpassing local resource limits.

Findings

NLA-based quantum repeaters are feasible with current technology.

Distributed quantum sensors with repeaters outperform local sensors.

The approach enables quantum advantage in sensing applications.

Abstract

Entanglement is a unique resource for quantum-enhanced applications. When employed in sensing, shared entanglement between distributed quantum sensors enables a substantial gain in the measurement sensitivity in estimating global parameters of the quantum sensor network. Loss incurred in the distribution of entanglement, however, quickly dissipates the measurement-sensitivity advantage enjoyed by the entangled quantum sensors over sensors supplied with local quantum resources. Here, we present a viable approach to overcome the entanglement-distribution loss and show that the measurement sensitivity enabled by entangled quantum sensors beat that afforded by the optimum local resource. Our approach relies on noiseless linear amplifiers (NLAs) to serve as quantum repeaters. We show that unlike the outstanding challenge of building quantum repeaters to suppress the repeaterless bound for quantum key distribution, NLA-based quantum repeaters for distributed quantum sensing are realizable by available technology. As such, distributed quantum sensing would become the first application instance that benefits from quantum repeaters.