Maximizing Thermal Entanglement of XY Model Using Site-Dependent Magnetic Fields in Specific Directions
CHAN Wen-Ling1, YANG Dong2, GU Shi-Jian1
1Department of Physics and ITP, The Chinese University of Hong Kong, Hong Kong2Laboratory for Quantum Information and Department of Physics, China Jiliang University, Hangzhou 310018
Maximizing Thermal Entanglement of XY Model Using Site-Dependent Magnetic Fields in Specific Directions
CHAN Wen-Ling1;YANG Dong2;GU Shi-Jian1
1Department of Physics and ITP, The Chinese University of Hong Kong, Hong Kong2Laboratory for Quantum Information and Department of Physics, China Jiliang University, Hangzhou 310018
摘要We study the thermal entanglement by means of concurrence in a two-qubit isotropic XY model in the presence of site-dependent external magnetic fields in arbitrary directions. We find that at a given temperature and magnetic field strength, the mirror symmetry of the two fields about the x--y plane is a necessary condition for maximum entanglement. However, if there is no constraint on the field strengths, then the necessary condition for maximum entanglement reduces to the configuration that the two fields are vertical, anti-parallel and with the same strength. We also investigate the anisotropic XY model and find that the above conclusion more or less holds.
Abstract：We study the thermal entanglement by means of concurrence in a two-qubit isotropic XY model in the presence of site-dependent external magnetic fields in arbitrary directions. We find that at a given temperature and magnetic field strength, the mirror symmetry of the two fields about the x--y plane is a necessary condition for maximum entanglement. However, if there is no constraint on the field strengths, then the necessary condition for maximum entanglement reduces to the configuration that the two fields are vertical, anti-parallel and with the same strength. We also investigate the anisotropic XY model and find that the above conclusion more or less holds.
(Quantized spin models, including quantum spin frustration)
引用本文:
CHAN Wen-Ling;YANG Dong;GU Shi-Jian. Maximizing Thermal Entanglement of XY Model Using Site-Dependent Magnetic Fields in Specific Directions[J]. 中国物理快报, 2008, 25(3): 832-835.
CHAN Wen-Ling, YANG Dong, GU Shi-Jian. Maximizing Thermal Entanglement of XY Model Using Site-Dependent Magnetic Fields in Specific Directions. Chin. Phys. Lett., 2008, 25(3): 832-835.
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2008, Vol. 25 
