Towards efficient quantum memory of orbital angular momentum qubits in cold atoms

TL;DR

This paper demonstrates efficient storage and retrieval of orbital angular momentum qubits in cold atoms, achieving high fidelity and efficiency, advancing the development of high-dimensional quantum networks.

Contribution

It presents the first high-fidelity, efficient quantum memory for OAM qubits in cold atoms using electromagnetically induced transparency.

Findings

Average fidelity above 98%

Retrieval efficiency around 65%

Suitable for high-dimensional quantum networks

Abstract

The spatial modes of light, carrying a quantized amount of orbital angular momentum (OAM), is one of the excellent candidates that provides access to high-dimensional quantum states, which essentially makes it promising towards building high-dimensional quantum networks. In this paper, we report the storage and retrieval of photonic qubits encoded with OAM state in the cold atomic ensemble, achieving an average conditional fidelity above 98% and retrieval efficiency around 65%. The photonic OAM qubits are encoded with weak coherent states at the single-photon level and the memory is based on electromagnetically induced transparency in an elongated cold rubidium atomic ensemble. Our work constitutes an efficient node that is needed towards high dimensional and large scale quantum networks.