Controllable quantum correlations of two-photon states generated using classically driven three-level atoms

TL;DR

This paper explores how two-photon quantum correlations generated by three-level atoms can be controlled and characterized, revealing their dependence on system parameters and potential for quantum information applications.

Contribution

It demonstrates controllable quantum correlations in two-photon states from three-level atoms, analyzing their hierarchy and steady-state behavior under various parameters.

Findings

Correlation properties are generic and model-independent.

MID bounds quantum discord and quantum work deficit.

Correlation hierarchy is controllable via atomic decay and driving fields.

Abstract

We investigate the dynamics of two-photon correlations generated by the interaction of a three-level atom in the $\Xi$, $\Lambda$ or V configuration, with two classical external driving fields, under the rotating-wave approximation, in the presence of level decays. Using the example of a rubidium atom in each configuration, with field strengths validating the single-photon approximation, we compute measurement based correlations, such as measurement induced disturbance (MID), quantum discord (QD), and quantum work deficit (WD), and compare the results with that of quantum entanglement (concurrence). Certain correlation properties observed are generic, model independent and consistent with known results, e.g., MID is an upper bound on QD, QD and WD are monotonic, and the generic correlation behavior is strongly affected by the purity of the photon states. We observe that the qualitative hierarchy, monotonicity and steady-state behavior of the correlations can be controlled by the choice of parameters such as atomic decay constants and external driving field strengths. We point out how particular configurations are better suited at generating monotonic correlations in specific regimes and how the steady-state correlation behavior and hierarchy are affected by the population dynamics of the density matrix for different parameters. The possibility of using well studied quantum optical systems such as the three-level atom to generate, characterize and parametrically control mixed state quantum correlations establishes an important step in the direction of their implementation in quantum information tasks.