Generation and propagation of entanglement in driven coupled-qubit systems

TL;DR

This paper demonstrates that driven coupled-qubit systems with separate reservoirs can generate and sustain entanglement in a stationary state, which can be propagated in quantum networks, offering potential for quantum circuit applications.

Contribution

It reveals a universal stationary entanglement phenomenon in driven coupled qubits with separate reservoirs and shows how this entanglement can be propagated in quantum networks.

Findings

Stationary entanglement exists in driven coupled-qubit systems with separate reservoirs.

The stationary state has a universal form independent of initial conditions.

Entanglement can be propagated using local unitary operations.

Abstract

In a bipartite system subject to decoherence from two separate reservoirs, the entanglement is typically destroyed faster than for single reservoirs. Surprisingly however, the existence of separate reservoirs can also have a beneficial entangling effect: if the qubits are coupled and driven externally by a classical field, the system ends up in a stationary state characterized by a finite degree of entanglement. This phenomenon occurs only in a certain region of the parameter space and the structure of the stationary state has a universal form which does not depend on the initial state or on the specific physical realization of the qubits. We show that the entanglement thus generated can be propagated within a quantum network using simple local unitary operations. We suggest the use of such systems as "batteries of entanglement" in quantum circuits.