Diffusion Effects in Gradient Echo Memory

TL;DR

This paper investigates how diffusion impacts the efficiency of a thermal gas-based gradient echo quantum memory, providing analytical and numerical insights and proposing methods to mitigate diffusion effects for better storage performance.

Contribution

It offers a detailed analysis of diffusion effects in $ ext{Lambda}$-gradient echo memory and suggests strategies to reduce decoherence caused by diffusion.

Findings

Diffusion significantly reduces memory efficiency over time.

Analytical and numerical models agree on diffusion's impact.

Proposed methods can mitigate diffusion effects.

Abstract

We study the effects of diffusion on a $\Lambda$-gradient echo memory, which is a coherent optical quantum memory using thermal gases. The efficiency of this memory is high for short storage time, but decreases exponentially due to decoherence as the storage time is increased. We study the effects of both longitudinal and transverse diffusion in this memory system, and give both analytical and numerical results that are in good agreement. Our results show that diffusion has a significant effect on the efficiency. Further, we suggest ways to reduce these effects to improve storage efficiency.