Noiseless loss suppression in quantum optical communication

TL;DR

This paper introduces a protocol that conditionally suppresses losses in quantum communication by noiselessly attenuating and amplifying quantum states, maintaining coherence and demonstrating experimental feasibility.

Contribution

It presents a novel loss suppression method combining noiseless attenuation and amplification, applicable to quantum states, with experimental validation in a specific subspace.

Findings

Successfully demonstrated loss suppression in vacuum and single-photon states

Maintains quantum coherence during loss mitigation

Potentially applicable to various quantum communication scenarios

Abstract

We propose a protocol for conditional suppression of losses in direct quantum state transmission over a lossy quantum channel. The method works by noiselessly attenuating the input state prior to transmission through a lossy channel followed by noiseless amplification of the output state. The procedure does not add any noise hence it keeps quantum coherence. We experimentally demonstrate it in the subspace spanned by vacuum and single-photon states, and consider its general applicability.