Polarization entanglement and quantum beats of photon pairs from four-wave mixing in a cold Rb-87 ensemble

TL;DR

This paper demonstrates polarization entanglement and quantum beats in photon pairs generated from cold Rb-87 atoms via four-wave mixing, revealing high-purity entangled states and temporal quantum interference effects.

Contribution

It provides a detailed characterization of polarization entanglement and quantum beats in photon pairs from cold atomic ensembles, advancing quantum light source understanding.

Findings

High-purity polarization entanglement achieved.

Observation of quantum beats in time-resolved correlations.

Correlation measurements confirm entanglement and quantum interference.

Abstract

We characterize correlations in polarization and time of photon pairs generated from a cold cloud of Rb-87 atoms via a four-wave mixing process in a cascade level scheme. Quantum state tomography reveals entangled polarization states of high purity for each of the decay paths through two different intermediate hyperfine levels. When allowing both decay paths, we observe quantum beats in time-resolved correlation measurements.