Quantum Memory with a controlled homogeneous splitting

TL;DR

This paper introduces a quantum memory protocol utilizing a controlled homogeneous splitting in atomic ensembles, enabling efficient, noise-free storage and retrieval of light without relying on ground state coherence or slow-light effects.

Contribution

The authors propose a novel quantum memory method based solely on a static homogeneous field, differing from existing protocols that depend on ground state coherence or photon-echo techniques.

Findings

Protocol achieves perfect efficiency when excited state lifetime exceeds storage time

The method is noise-free under ideal conditions

Suitable atomic systems for experimental realization are discussed

Abstract

We propose a quantum memory protocol where a input light field can be stored onto and released from a single ground state atomic ensemble by controlling dynamically the strength of an external static and homogeneous field. The technique relies on the adiabatic following of a polaritonic excitation onto a state for which the forward collective radiative emission is forbidden. The resemblance with the archetypal Electromagnetically-Induced-Transparency (EIT) is only formal because no ground state coherence based slow-light propagation is considered here. As compared to the other grand category of protocols derived from the photon-echo technique, our approach only involves a homogeneous static field. We discuss two physical situations where the effect can be observed, and show that in the limit where the excited state lifetime is longer than the storage time, the protocols are perfectly efficient and noise-free. We compare the technique to other quantum memories, and propose atomic systems where the experiment can be realized.