Efficient decoherence-free entanglement distribution over lossy quantum channels

TL;DR

This paper presents a scheme that significantly improves the efficiency of distributing entanglement over lossy quantum channels by utilizing a decoherence-free subspace and backward propagation of coherent light, achieving rates proportional to channel transmittance.

Contribution

The authors introduce a novel scheme that enhances entanglement distribution efficiency over lossy channels using DFS and backward light propagation, with experimental validation.

Findings

Entanglement-sharing rate is proportional to channel transmittance T.

Highly entangled states violating Bell inequality are distributed.

Experimental demonstration confirms theoretical predictions.

Abstract

We propose and demonstrate a scheme for boosting up the efficiency of entanglement distribution based on a decoherence-free subspace (DFS) over lossy quantum channels. By using backward propagation of a coherent light, our scheme achieves an entanglement-sharing rate that is proportional to the transmittance T of the quantum channel in spite of encoding qubits in multipartite systems for the DFS. We experimentally show that highly entangled states, which can violate the Clauser-Horne-Shimony-Holt inequality, are distributed at a rate proportional to T.