Optical quantum memory

TL;DR

Optical quantum memory is crucial for quantum computing and communication, serving as a synchronization tool, quantum gate, and photon source, with various mechanisms being actively researched.

Contribution

This paper reviews the current state-of-the-art, criteria, and performance levels of optical quantum memory mechanisms.

Findings

Multiple mechanisms like EIT and photon-echo are studied for quantum memory.

Performance benchmarks vary across different optical quantum memory systems.

Optical quantum memory is essential for scalable quantum networks.

Abstract

Quantum memory is important to quantum information processing in many ways: a synchronization device to match various processes within a quantum computer, an identity quantum gate that leaves any state unchanged, and a tool to convert heralded photons to photons-on-demand. In addition to quantum computing, quantum memory would be instrumental for the implementation of long-distance quantum communication using quantum repeaters. The importance of this basic quantum gate is exemplified by the multitude of optical quantum memory mechanisms being studied: optical delay lines, cavities, electromagnetically-induced transparency, photon-echo, and off-resonant Faraday interaction. Here we report on the state-of-the-art in the field of optical quantum memory, including criteria for successful quantum memory and current performance levels.