Entanglement of Two-Qubit Quantum Heisenberg XYZ Chain
XI Xiao-Qiang1,2, HAO San-Ru1, CHEN Wen-Xue2, YUE Rui-Hong1
1Institute of Modern Physics, Northwest University,
Xi’an 710069
2Fundamental Department of Xi’an Institute of Posts and Telecommunications, Xi’an 710061
Entanglement of Two-Qubit Quantum Heisenberg XYZ Chain
XI Xiao-Qiang1,2;HAO San-Ru1;CHEN Wen-Xue2;YUE Rui-Hong1
1Institute of Modern Physics, Northwest University,
Xi’an 710069
2Fundamental Department of Xi’an Institute of Posts and Telecommunications, Xi’an 710061
Abstract： We derive the analytic expression of the concurrence in the quantum Heisenberg XYZ model and discuss the influence of parameters J, Δ, and Γ on the concurrence. By choosing different values Γ and Δ, we obtain the XX, XY, XXX and XXZ chains. The concurrence decreases with increasing temperature. When T → 0, the concurrence reaches its maximum value 1, i.e., the entangled state, | > = √2/2 (|01> - |10>), is maximum entanglement. For the XXZ chain, when Γ → ∞, the concurrence will meet its maximum value Cmax = sinh(1/T)/cosh(1/T).
2002, Vol. 19 
