Storage of multiple coherent microwave excitations in an electron spin ensemble

TL;DR

This paper demonstrates a quantum memory system using electron spin ensembles to store and retrieve multiple microwave excitations, with the ability to transfer information to nuclear spins for extended coherence times.

Contribution

It introduces a method for storing multiple microwave excitations in an electron spin ensemble and transferring them to nuclear spins for long-term storage.

Findings

Stored and retrieved up to 100 microwave excitations

Successfully transferred excitations to nuclear spins with coherence times over seconds

Used pulsed magnetic field gradients for holographic storage

Abstract

Electron and nuclear spins have good coherence times and an ensemble of spins is a promising candidate for a quantum memory. By employing holographic techniques via field gradients a single ensemble may be used to store many bits of information. Here we present a coherent memory using a pulsed magnetic field gradient, and demonstrate the storage and retrieval of up to 100 weak 10 GHz coherent excitations in collective states of an electron spin ensemble. We further show that such collective excitations in the electron spin can then be stored in nuclear spin states, which offer coherence times in excess of seconds.