Entanglement production due to quench dynamics of an anisotropic XY chain in a transverse field

TL;DR

This paper investigates how a power-law quench across a quantum critical point in an anisotropic XY chain generates two-site entanglement, revealing critical quench rates and scaling behaviors related to defect production.

Contribution

It demonstrates that only even-neighbor pairs become entangled during a power-law quench and identifies a critical quench rate beyond which entanglement is multipartite.

Findings

Only even-neighbor pairs get entangled.

A critical quench rate exists above which no two-site entanglement is produced.

Concurrence and negativity scale as sqrt{alpha/tau} and alpha/tau for large tau.

Abstract

We compute concurrence and negativity as measures of two-site entanglement generated by a power-law quench (characterized by a rate 1/tau and an exponent alpha) which takes an anisotropic XY chain in a transverse field through a quantum critical point (QCP). We show that only the even-neighbor pairs of sites get entangled in such a process. Moreover, there is a critical rate of quench, 1/tau_c, above which no two-site entanglement is generated; the entire entanglement is multipartite. The ratio of the two-site entanglements between consecutive even neighbors can be tuned by changing the quench rate. We also show that for large tau, the concurrence (negativity) scales as sqrt{alpha/tau} (alpha/tau), and we relate this scaling behavior to defect production by the quench through a QCP.