Long-time Protection of Nonlocal Entanglement

TL;DR

This paper explores how structured environments can be engineered to preserve nonlocal entanglement, identified via Bell inequality violations, over long periods in two-qubit systems interacting with reservoirs.

Contribution

It demonstrates that population trapping in structured environments can be used to protect nonlocal entanglement during evolution.

Findings

Bell inequality violation relates to excited state population.

Structured environments enable long-term entanglement protection.

Population trapping correlates with sustained nonlocal entanglement.

Abstract

We investigate how nonlocal entanglement, as identified by violations of a Bell inequality, may be protected during the evolution. Our system consists of two qubits each embedded in a bosonic reservoir evolving independently and initially in an entangled mixed state. We show that the violation of the Bell inequality can be related to the single-qubit population of excited state in such a way that, by appropriately choosing structured environments that give rise to sufficiently high values of population trapping, long-time protection of nonlocal entanglement can be correspondingly achieved.