Quantum Memories. A Review based on the European Integrated Project "Qubit Applications (QAP)"

TL;DR

This review comprehensively examines various physical implementations and performance criteria of quantum memories, highlighting approaches within the EU's Qubit Applications project, including solid-state and atomic systems.

Contribution

It provides a detailed comparison of diverse quantum memory approaches under a unified framework, emphasizing the EU project’s specific contributions.

Findings

Solid-state atomic ensembles show promising coherence times.

NV centers and quantum dots are viable for scalable quantum memories.

Performance varies significantly across different physical implementations.

Abstract

We perform a review of various approaches to the implementation of quantum memories, with an emphasis on activities within the quantum memory sub-project of the EU Integrated Project "Qubit Applications". We begin with a brief overview over different applications for quantum memories and different types of quantum memories. We discuss the most important criteria for assessing quantum memory performance and the most important physical requirements. Then we review the different approaches represented in "Qubit Applications" in some detail. They include solid-state atomic ensembles, NV centers, quantum dots, single atoms, atomic gases and optical phonons in diamond. We compare the different approaches using the discussed criteria.