Mutual Preservation of Entanglement

TL;DR

This paper investigates how entanglement can be preserved in a generalized double Jaynes-Cummings model with two entangled pairs of atoms, demonstrating conditions for continuous entanglement and extending results to multi-mode interactions.

Contribution

It introduces a generalized model showing persistent entanglement in two entangled pairs and extends the analysis to multi-mode atom-cavity systems using non-Markovian dynamics.

Findings

Existence of initial states maintaining entanglement at all times

Minimum entanglement depends on initial state

Multi-mode interactions also preserve entanglement

Abstract

We study a generalized double Jaynes-Cummings (JC) model where two entangled pairs of two-level atoms interact indirectly. We focus on the case where the cavities and the entangled pairs are uncorrelated. We show that there exist initial states of the qubit system so that two entangled pairs are available at all times. In particular, the minimum entanglement in the pairs as a function of the initial state is studied. Finally, we extend our findings to a model consisting of multi-mode atom-cavity interactions. We use a non-Markovian quantum state diffusion (QSD) equation to obtain the steady-state density matrix for the qubits. We show that the multi-mode model also displays dynamical preservation of entanglement.