Entanglement swapping via lossy channels using photon-number-encoded states

TL;DR

This paper presents a photon-number-encoded entanglement swapping protocol that reduces the impact of channel losses in quantum networks, achieving linear success probability scaling without the need for quantum memories.

Contribution

It introduces a novel entanglement swapping method using photon-number encoding that mitigates channel loss effects without requiring photonic quantum memories.

Findings

Success probability scales linearly with channel transmission

Optimal initial states can compensate for unbalanced losses

Experimental validation confirms theoretical predictions

Abstract

Entanglement shared between distant parties is a key resource in quantum networks. However, photon losses in quantum channels significantly reduce the success probability of entanglement sharing, which scales quadratically with the channel transmission. Quantum repeaters using entanglement swapping can mitigate this effect, but usually require high-performance photonic quantum memories to synchronize photonic qubits. In this work, we theoretically and experimentally investigate an entanglement swapping protocol using photon-number-encoded states that can effectively alleviate quantum channel losses without requiring photonic quantum memories. We demonstrate that the protocol exhibits a success probability scaling linearly with the channel transmission. Furthermore, we show that while unbalanced channel losses can degrade the shared entanglement, this effect can be compensated by optimally adjusting the initial entangled states. Our results highlight the potential of photon-number encoding for realizing robust entanglement distribution in lossy quantum networks.