Storage and retrieval of continuous-variable polarization-entangled cluster states in atomic ensembles

TL;DR

This paper proposes a method to store and retrieve continuous-variable polarization-entangled cluster states in atomic ensembles, enabling long-term quantum information storage with feasible experimental conditions.

Contribution

It introduces a novel scheme utilizing atomic ensembles and Larmor precession to store and retrieve polarization-entangled states with high fidelity.

Findings

Scheme is feasible under realistic experimental conditions

High fidelity of storage and retrieval demonstrated through variance analysis

Utilizes symmetry in atomic canonical operators for effective state mapping

Abstract

We present a proposal for storing and retrieving a continuous-variable quadripartite polarization-entangled cluster state, using macroscopic atomic ensembles in a magnetic field. The Larmor precession of the atomic spins leads to a symmetry between the atomic canonical operators. In this scheme, each of the four spatially separated pulses passes twice through the respective ensemble in order to map the polarization-entangled cluster state onto the long-lived atomic ensembles. The stored state can then be retrieved by another four read-out pulses, each crossing the respective ensemble twice. By calculating the variances, we analyzed the fidelities of the storage and retrieval, and our scheme is feasible under realistic experimental conditions.