Entanglement Protection of Classically Driven Qubits in a Lossy Cavity

TL;DR

This paper explores how classical driving fields can protect and generate entanglement between two qubits in a lossy environment, identifying conditions for stationary maximally entangled states and demonstrating entanglement creation from initial separable states.

Contribution

It reveals the constructive role of classical driving in entanglement protection and generation, especially in the strong coupling regime, and identifies a stationary subspace independent of environment properties.

Findings

Classical driving can protect entanglement against environmental decay.

A stationary subspace allows for environment-independent maximally entangled states.

Initial separable states can be driven into entangled steady-states.

Abstract

Quantum technologies able to manipulating single quantum systems, are presently developing. Among the dowries of the quantum realm, entanglement is one of the basic resources for the novel quantum revolution. Within this context, one is faced with the problem of protecting the entanglement when a system state is manipulated. In this paper, we investigate the effect of the classical driving field on the generation entanglement between two qubits interacting with a bosonic environment. We discuss the effect of the classical field on the generation of entanglement between two (different) qubits and the conditions under which it has a constructive role in protecting the initial-state entanglement from decay induced by its environment. In particular, in the case of similar qubits, we locate a stationary sub-space of the system Hilbert space, characterized by states non depending on the environment properties as well as on the classical driving-field. Thus, we are able to determine the conditions to achieve maximally entangled stationary states after a transient interaction with the environment. We show that, overall, the classical driving field has a constructive role for the entanglement protection in the strong coupling regime. Also, we illustrate that a factorable initial-state can be driven in an entangled state and, even, in an entangled steady-state after the interaction with the environment.