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arXiv:quant-ph/0101013 · Physical Review A

Entanglement in the quantum Heisenberg XY model

Xiaoguang Wang

Published Jun 12, 2001• 576 citations
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Abstract

We study the entanglement in the quantum Heisenberg $\mathrm{XY}$ model in which the so-called W entangled states can be generated for 3 or 4 qubits. By the concept of concurrence, we study the entanglement in the time evolution of the $\mathrm{XY}$ model. We investigate the thermal entanglement in the two-qubit isotropic $\mathrm{XY}$ model with a magnetic field and in the anisotropic $\mathrm{XY}$ model, and find that the thermal entanglement exists for both ferromagnetic and antiferromagnetic cases. Some evidences of the quantum phase transition also appear in these simple models.

DOI
10.1103/physreva.64.012313

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