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

Abstract

We compute concurrence and negativity as measures of two-spin entanglement generated by a power-law quench (characterized by a rate τ⁻¹ and an exponent a) which takes an anisotropic XY chain in a transverse field through a quantum critical point (QCP). We show that only spins separated by an even number of lattice spacings get entangled in such a process. Moreover, there is a critical rate of quench, τ_c⁻¹, above which no two-spin entanglement is generated; the entire entanglement is multipartite. The ratio of the entanglements between consecutive even neighbors can be tuned by changing the quench rate. We also show that for large τ, the concurrence (negativity) scales as √α/τ (α/τ), and we relate this scaling behavior to defect production by the quench through a QCP.