A high-performance quantum memory for quantum interconnects

TL;DR

This paper presents a high-performance quantum memory capable of storing high-dimensional quantum states with high efficiency and fidelity, significantly advancing quantum communication over long distances.

Contribution

The authors introduce a comprehensive quantum interconnect rate metric and demonstrate a quantum memory with large multimode capacity, high efficiency, and fidelity simultaneously.

Findings

Achieves over 80% efficiency across 11 spatial modes

Maintains qubit fidelity above 99%

Enables distribution of 3.56 bits of quantum information over 1000 km in one minute

Abstract

Single photons are the flying qubits of choice for distributing entanglement in a quantum internet. Quantum memories embedded in quantum repeaters are crucial to overcome transmission loss and enhance the rate of quantum communication. A multimode memory can further boost the channel capacity. However, benchmarking and building a practical quantum memory that simultaneously optimizes multiple performance metrics poses two key challenges. Here, we introduce quantum interconnect rate to comprehensively quantify quantum memories, and further demonstrate a high-performance quantum memory that simultaneously integrates three essential criteria at once: large multimode capacity, high efficiency, and high fidelity. Operating on 11-dimensional spatial modes, our memory achieves a uniform efficiency exceeding 80% and qubit storage fidelities above 99%, enabling the efficient storage of high-dimensional qudits. Based on these capabilities, we estimate a distribution of 3.56 bits of quantum information over a 1000-km repeater link in one minute, highlighting a practical pathway toward scalable quantum interconnects and quantum networks.