Thermal entanglement in a two-qubit Heisenberg XXZ spin chain under an inhomogeneous magnetic field

Abstract

The thermal entanglement in a two-qubit Heisenberg \emph{XXZ} spin chain is investigated under an inhomogeneous magnetic field \emph{b}. We show that the ground-state entanglement is independent of the interaction of \emph{z}-component $J_z$. The thermal entanglement at the fixed temperature can be enhanced when $J_z$ increases. We strictly show that for any temperature \emph{T} and $J_z$ the entanglement is symmetric with respect to zero inhomogeneous magnetic field, and the critical inhomogeneous magnetic field $b_c$ is independent of $J_z$. The critical magnetic field $B_c$ increases with the increasing $|b|$ but the maximum entanglement value that the system can arrive becomes smaller.

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