Controllable-dipole quantum memory

TL;DR

This paper introduces a quantum memory protocol utilizing direct control of the transition dipole moment, optimized through a time-reversal symmetry, with potential implementation in rare-earth ion doped crystals.

Contribution

It proposes a novel quantum memory scheme based on controllable dipole moments and demonstrates its optimal operation via time-reversal symmetry in cavity-enhanced systems.

Findings

Optimal write and read processes are related by a reversal of effective time.

The protocol can be implemented in rare-earth ion doped crystals with magnetic field switching.

Enhanced light-matter interaction improves storage efficiency.

Abstract

We present a quantum memory protocol for photons that is based on the direct control of the transition dipole moment. We focus on the case where the light-matter interaction is enhanced by a cavity. We show that the optimal write process (maximizing the storage efficiency) is related to the optimal read process by a reversal of the {\it effective time} $\tau=\int dt g^2(t)/\kappa$, where $g(t)$ is the time-dependent coupling and $\kappa$ is the cavity decay rate. We discuss the implementation of the protocol in a rare-earth ion doped crystal, where an optical transition can be turned on and off by switching a magnetic field.