Fidelity of photon propagation in electromagnetically induced transparency in the presence of four-wave mixing

TL;DR

This paper investigates how four-wave mixing impacts the fidelity of photon propagation in EIT-based quantum memories, revealing conditions where 4WM degrades quantum storage capabilities.

Contribution

It provides a quantum mechanical analysis of 4WM effects on photon fidelity in EIT, identifying parameter regimes that hinder quantum memory performance.

Findings

4WM can be detrimental to quantum memory fidelity

Quantum noise from 4WM affects single-photon storage

Certain parameters make 4WM incompatible with quantum memory

Abstract

We study the effects of the four-wave mixing (4WM) in a quantum memory scheme based on electromagnetically induced transparency (EIT). We treat the problem of field propagation on the quantum mechanical level, which allows us to calculate the fidelity for propagation for a quantum light pulse such as a single photon. While 4WM can be beneficial for classical, all-optical information storage, the quantum noise associated with the signal amplification and idler generation is in general detrimental for a quantum memory. We identify a range of parameters where 4WM makes a single photon quantum memory impossible.