Multicell Atomic Quantum Memory as a Hardware-Efficient Quantum Repeater Node

TL;DR

This paper demonstrates a compact, efficient quantum repeater node using multicell atomic quantum memories with long coherence times, enabling scalable quantum networks through heralded entanglement and on-demand qubit storage.

Contribution

It introduces a novel multicell atomic quantum memory with millisecond lifetime, enabling efficient entanglement generation and on-demand qubit storage in quantum repeater nodes.

Findings

Achieved millisecond coherence time for multicell quantum memories.

Demonstrated heralded asynchronous entanglement generation.

Implemented on-demand retrieval of atomic spin-wave qubits.

Abstract

For scalable quantum communication and networks, a key step is to realize a quantum repeater node that can efficiently connect different segments of atom-photon entanglement using quantum memories. We report a compact and hardware-efficient realization of a quantum repeater node using a single atomic ensemble for multicell quantum memories. Millisecond lifetime is achieved for individual memory cells after suppressing the magnetic-field-induced inhomogeneous broadening and the atomic-motion-induced spin-wave dephasing. Based on these long-lived multicell memory cells, we achieve heralded asynchronous entanglement generation in two quantum repeater segments one after another and then an on-demand entanglement connection of these two repeater segments. As another application of the multicell atomic quantum memory, we further demonstrate storage and on-demand retrieval of heralded atomic spin-wave qubits by implementing a random access quantum memory with individual addressing capacity. This work provides a promising constituent for efficient realization of quantum repeaters for large-scale quantum networks.