Abstract:

The bounds of entanglement on antiferromagnetic (AF) isotropic Heisenberg spin-1/2 chain including dipole- dipole interaction (D) were investigated. The Quantum Monte Carlo method based on loop algorithm was employed to calculate the two-spin and single-spin expectation values mediating the lower and upper bounds. It was revealed that D and Bz (the applied magnetic field) were pivotal parameters in controlling either entanglement creation/extinction or entanglement enhancement/weakening. Rival regions indicated a revival phenomenon depending on the temperature for various strengths of D which also showed a nonmonotonic behavior under certain Bz identifying critical points. Even if thermal agitations break the stability of strong D entanglement, it remains invariable at very low temperatures.

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