摘要
We investigate the entanglement of the three-qubit Heisenberg XXX chain in the presence of impurity and obtain the analytical expressions of the concurrence C. It is found that for impurity entanglement, C appears only when J 1 > J for J > 0, and J 1 > 0 for J < 0, and in these two regions C increases with the increase of J 1, so is the critical temperature T c. When J 1 ? | J |, C reaches its maximum value 0.5 and T c reaches the asymptotic value T c = 3.41448J 1. For entanglement between the normal lattices, C appears only when J > 0 and ?2J < J 1 < J, and initially increases with the increase of J 1 and arrives at the maximum value C max = (e4J/T ?3)/(e4J/T + 3) before it decays to zero gradually, so is the critical temperature T c with, however, the maximum value T cmax = 4J/In3.
We investigate the entanglement of the three-qubit Heisenberg XXX chain in the presence of impurity and obtain the analytical expressions of the concurrence C. It is found that for impurity entanglement, C appears only when J1 > J for J > 0, and J1 > 0 for J < 0, and in these two regions C increases with the increase of J1, so is the critical temperature Tc. When J1 >>|J| , C reaches its maximum value 0.5 and Tc reaches the asymptotic value Tc = 3.41448J1. For entanglement between the normal lattices, C appears only when J > 0 and 2J < J1 < J, and initially increases with the increase of J1 and arrives at the maximum value Cmax = (e4JIT-3)/(e4JIT+3) before it decays to zero gradually, so is the critical temperature Tc with, however, the maximum value Tcmax = 4J/ln3.
基金
the Natural Science Research Project of Shaanxi Province(Grant No. 2004A15)
