Efficient reversible entanglement transfer between light and quantum memories

TL;DR

This paper demonstrates highly efficient reversible transfer of single-photon entanglement between light and cold atomic ensembles, achieving 85% efficiency crucial for scalable quantum networks.

Contribution

It reports the first demonstration of 85% efficiency in entanglement transfer between light and matter using cold cesium atom ensembles, advancing quantum network capabilities.

Findings

Achieved 85% storage-and-retrieval efficiency.

Preserved two-photon suppression of about 10%.

Enabled reversible entanglement transfer for quantum networks.

Abstract

Reversible entanglement transfer between light and matter is a crucial requisite for the ongoing developments of quantum information technologies. Quantum networks and their envisioned applications, e.g., secure communications beyond direct transmission, distributed quantum computing or enhanced sensing, rely on entanglement distribution between nodes. Although entanglement transfer has been demonstrated, a current roadblock is the limited efficiency of this process that can compromise the scalability of multi-step architectures. Here we demonstrate the efficient transfer of heralded single-photon entanglement into and out-of two quantum memories based on large ensembles of cold cesium atoms. We achieve an overall storage-and-retrieval efficiency of 85% together with a preserved suppression of the two-photon component of about 10% of the value for a coherent state. Our work constitutes an important capability that is needed towards large scale networks and increased functionality.