Entanglement replication via quantum repeated interactions

TL;DR

This paper demonstrates how repeated local interactions with Bell pairs can generate and transfer entanglement between two independent quantum spin chains, resulting in large-scale correlations and a non-equilibrium steady state.

Contribution

It provides an analytical study of entanglement transfer via repeated local interactions, revealing the formation of a non-equilibrium steady state with exponential decay of entanglement.

Findings

Perfect entanglement transfer in the steady state.

Exponential decay of entanglement with distance in the NESS.

Identification of a causal region with a current-driven non-equilibrium state.

Abstract

We study entanglement creation between two independent XX chains, which are repeatedly coupled locally to spin-1/2 Bell pairs. We show analytically that in the steady state the entanglement of the Bell pairs is perfectly transferred to the chains, generating large-scale interchain pair correlations. However, before the steady state is reached, within a growing causal region around the interacting locus the chains are found in a current driven nonquilibrium steady state (NESS). In the NESS, the chains cross entanglement decays exponentially with respect to the distance to the boundary sites with a typical length scale which is inversely proportional to the driving current.