Manipulation of two quantum systems through their mutual interaction in presence of a radiation field

TL;DR

This paper provides an exact analytic solution for the dynamics of two interacting quantum systems coupled to a radiation field, revealing how their mutual interaction influences entanglement and non-classical properties in cavity QED.

Contribution

It introduces a novel exact solution for two coupled two-level systems in a radiation field, analyzing how their mutual interaction affects quantum dynamics and entanglement.

Findings

Coupling ratio affects collapse-revival patterns and entanglement dynamics.

Increasing coupling ratio enhances entanglement and oscillation amplitude.

Higher coupling ratios extend revival times significantly.

Abstract

In cavity QED, the mutual interaction between natural atomic systems in presence of a radiation field was ignored due to its negligible impact compared with the coupling to the field. The newly engineered artificial atomic systems (such as quantum dots and superconducting circuits) proposed for quantum information processing enjoy strong interaction with same type of systems or even with other types in hybrid structures, which is coherently controllable and moreover they can be efficiently coupled to radiation fields. We present an exact analytic solution for the time evolution of a composite system of two interacting two-level quantum systems coupled to a single mode radiation field, which can be realized in cavity (circuit) QED. We show how the non-classical dynamical properties of the composite system are affected and can be tuned by introducing and varying the mutual coupling between the two systems. Particularly, the collapse-revival pattern shows a splitting during the revival intervals as the coupling ratio (system-system to system-field) increases, which is a sign of an interruption in the system-radiation energy exchange process. Furthermore, the time evolution of the bipartite entanglement between the two systems is found to vary significantly depending on the coupling ratio as well as the initial state of the composite system resulting in either an oscillatory behavior or a collapse-revival like pattern. Increasing the coupling ratio enhances the entanglement, raises its oscillation average value and emphasizes the collapse-revival like pattern. However, raising the coupling ratio beyond unity increases the revival time considerably. The effect of the other system parameters such as detuning and radiation field intensity on the system dynamics has been investigated as well.