Abstract

We identify a simple experimental setting of a locally pumped and lossy array of two-level quantum systems that can stabilize multiple highly coherent steady states. By analytic construction, we show there is an extensive set of steady-state density operators, from minimally to maximally entangled, despite this being an interacting open many-body problem. These nonequilibrium states arise from a hidden symmetry that stabilizes Bell pairs over arbitrarily long distances, leading to controllable long-range entanglement. We show how to selectively prepare and observe the steady states in existing setups. Our conclusions apply to a broad range of two-level systems.

The talk will be based on [1] arXiv 2004.07981 (main reference) [2] arXiv 2007.08938.