Quantum Coherence and Correlations of optical radiation by atomic ensembles interacting with a two-level atom in microwave cavity

TL;DR

This paper investigates the quantum statistical properties and entanglement of optical photons emitted from atomic ensembles coupled with a two-level atom in a microwave cavity, exploring both steady and non-equilibrium states.

Contribution

It introduces a comprehensive analysis of quantum correlations, coherence, and entanglement in a hybrid atomic-microwave optical system, including potential experimental implementations.

Findings

Analysis of second order coherence and quantum correlations.

Identification of conditions for quantum state transfer and entanglement.

Proposal for experimental realization in superconducting resonators with diamond NV centers.

Abstract

We examine quantum statistics of optical photons emitted from atomic ensembles which are classically driven and simultaneously coupled to a two-level atom via microwave photon exchange. Quantum statistics and correlations are analyzed by calculating second order coherence degree, von Neumann entropy, spin squeezing for multi-particle entanglement, as well as genuine two and three-mode entanglement parameters for steady state and non-equilibrium situations. Coherent transfer of population between the radiation modes and quantum state mapping between the two-level atom and the optical modes are discussed. A potential experimental realization of the theoretical results in a superconducting coplanar waveguide resonator containing diamond crystals with Nitrogen-Vacancy color centers and a superconducting artificial two-level atom is discussed.