What can we learn from the dynamics of entanglement and quantum discord in the Tavis-Cummings model?

TL;DR

This paper analyzes the dynamics of quantum correlations, specifically entanglement and quantum discord, in the exact Tavis-Cummings model, revealing complex behaviors and potential experimental applications without relying on dissipation effects.

Contribution

It provides a comprehensive analytical study of quantum correlation dynamics in the exact Tavis-Cummings model, highlighting non-trivial behaviors and proposing experimental quantum discord gates.

Findings

Quantum discord dynamics are influenced by non-linearities and initial conditions.

States with opposite quantum correlation measures can coexist.

Proposed quantum discord gates depend on photon number.

Abstract

We revisit the problem of the dynamics of quantum correlations in the exact Tavis-Cummings model. We show that many of the dynamical features of quantum discord attributed to dissipation are already present in the exact framework and are due to the well known non-linearities in the model and to the choice of initial conditions. Through a comprehensive analysis, supported by explicit analytical calculations, we find that the dynamics of entanglement and quantum discord are far from being trivial or intuitive. In this context, we find states that are indistinguishable from the point of view of entanglement and distinguishable from the point of view of quantum discord, states where the two quantifiers give opposite information and states where they give roughly the same information about correlations at a certain time. Depending on the initial conditions, this model exhibits a fascinating range of phenomena that can be used for experimental purposes such as: Robust states against change of manifold or dissipation, tunable entanglement states and states with a counterintuitive sudden birth as the number of photons increase. We furthermore propose an experiment called quantum discord gates where discord is zero or non-zero depending on the number of photons.