Long-Lived Solid-State Optical Memory for High-Rate Quantum Repeaters.

Mohsen Falamarzi Askarani,Wolfgang Tittel,Sara Marzban,Neil Sinclair,Gustavo C Amaral,Joshua A Slater,Antariksha Das,Charles W Thiel,Daniel Oblak,Jacob H Davidson,Rufus L Cone

doi:10.1103/physrevlett.127.220502

Abstract

We argue that long optical storage times are required to establish entanglement at high rates over large distances using memory-based quantum repeaters. Triggered by this conclusion, we investigate the 795.325 nm^{3} H_{6}↔^{3}H_{4} transition of Tm:Y_{3}Ga_{5}O_{12} (Tm:YGG). Most importantly, we find that the optical coherence time can reach 1.1ms, and, using laser pulses, we demonstrate optical storage based on the atomic frequency comb protocol during up to 100 μs as well as a memory decay time T_{m} of 13.1 μs. Possibilities of how to narrow the gap between the measured value of T_{m} and its maximum of 275 μs are discussed. In addition, we demonstrate multiplexed storage, including with feed-forward selection, shifting and filtering of spectral modes, as well as quantum state storage using members of nonclassical photon pairs. Our results show the potential of Tm:YGG for creating multiplexed quantum memories with long optical storage times, and open the path to repeater-based quantum networks with high entanglement distribution rates.

Highlights

We argue that long optical storage times are required to establish entanglement at high rates over large distances using memory-based quantum repeaters
We find that the optical coherence time can reach 1.1 ms, and, using laser pulses, we demonstrate optical storage based on the atomic frequency comb protocol during up to 100 μs as well as a memory decay time Tm of 13.1 μs
One example is that of temporal multiplexing and read-out on demand in the so-called atomic frequency comb (AFC) quantum memory protocol, which requires one to temporarily map qubit states between optical and spin coherence [16]

Summary

Introduction

We argue that long optical storage times are required to establish entanglement at high rates over large distances using memory-based quantum repeaters. We find that the optical coherence time can reach 1.1 ms, and, using laser pulses, we demonstrate optical storage based on the atomic frequency comb protocol during up to 100 μs as well as a memory decay time Tm of 13.1 μs.

Results

Conclusion