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arXiv · 0904.1946

Thermal entanglement of one-dimensional Heisenberg quantum spin chains in magnetic fields

Shou-Shu Gong·Gang Su
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Abstract

The thermal pairwise entanglement (TE) of the S=1/2 XY chain in a transverse magnetic field is exactly resolved by means of the Jordan-Wigner transformation. It is found that the TE vanishes at a common temperature Tc~0.4843J, which is irrelevant to the field. A thermal quantity is proposed to witness the entangled state. Furthermore, the TE of the S=1/2 antiferromagnetic-ferromagnetic (AF-F) Heisenberg chain is studied by the transfer-matrix renormalization group method.The TEs of the spins coupled by AF and F interactions are found to behave distinctively. The vanishing temperature of the field-induced TE of the spins coupled by F interactions is observed to change with the magnetic field. The results are further confirmed and analyzed by the mean-field theory.

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Shou-Shu Gong, Gang Su. 2009-07-02. Thermal entanglement of one-dimensional Heisenberg quantum spin chains in magnetic fields. https://doi.org/10.1103/physreva.80.012323

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