# Storage and retrieval of time-entangled soliton trains in a three-level atom system coupled to an optical cavity

## TL;DR

This paper presents a method for storing and retrieving time-entangled photon trains in a three-level atom system using cavity Electromagnetically-Induced Transparency, enabling controlled quantum memory for quantum communication.

## Contribution

It introduces an analytic scheme for complete transfer and retrieval of complex photon states in a cavity-atom system under impedance matching conditions.

## Key findings

- Successful transfer and retrieval of Gaussian and hyperbolic-secant photon pulses.
- Controlled storage and retrieval of time-entangled photon trains.
- Potential for multiplexed quantum communication applications.

## Abstract

The storage and subsequent retrieval of coherent pulse trains in the quantum memory (i.e. cavity-dark state) of three-level $\Lambda$ atoms, are considered for an optical medium in which adiabatic photon transfer occurs under the condition of quantum impedance matching. The underlying mechanism is based on intracavity Electromagnetically-Induced Transparency, by which properties of a cavity filled with three-level $\Lambda$-type atoms are manipulated by an external control field. Under the impedance matching condition, we derive analytic expressions that suggest a complete transfer of an input field into the cavity-dark state by varying the mixing angle in a specific way, and its subsequent retrieval at a desired time. We illustrate the scheme by demonstrating the complete transfer and retrieval of a Gaussian, a single hyperbolic-secant and a periodic train of time-entangled hyperbolic-secant input photon pulses in the atom-cavity system. For the time-entangled hyperbolic-secant input field, a total controllability of the periodic evolution of the dark state population is made possible by changing the Rabi frequency of the classical driving field, thus allowing to alternately store and retrieve high-intensity photons from the optically dense Electromagnetically-Induced transparent medium. Such multiplexed photon states, which are expected to allow sharing quantum information among many users, are currently of very high demand for applications in long-distance and multiplexed quantum communication.