具有三体相互作用的自旋系统纠缠性质研究

Study on Entanglement Properties of Spin Systems With Three-body Interaction

研究了具有三体相互作用的三格点混合自旋(1/2,1,1/2),(1,1/2,1)铁磁XX系统的量子纠缠性质.探究了不同的自旋间纠缠随外界温度与三体相互作用的变化规律.研究发现当温度高于某个阈值时纠缠消失.对于自旋系统(1/2,1,1/2),自旋1/2和1的两格点间的纠缠消失的阈值温度随三体相互作用的增大而减小,而自旋1/2的两格点的阈值温度保持不变.当温度接近绝对零温时,这两种纠缠随三体相互作用的突变行为可以反映系统的基态突变.对于(1,1/2,1)混合自旋系统,自旋1和1/2的两格点间的阈值温度随三体相互作用的增大而减小,而自旋为1的两格点的阈值温度随三体相互作用的增大而增大.只有自旋1和1/2的两格点间的纠缠突变行为可以反映系统基态突变.这两种系统的纠缠均体现出了单配性原则.

The quantum entanglement properties of three-sites mixed spin(1/2,1,1/2)and(1,1/2,1)ferromagnetic XX systems with three body interactions are studied.It is found that the entanglement vanishes when the temperature is higher than a certain threshold.For mixed spin(1/2,1,1/2)system,the threshold temperature,at which entanglement between the spin 1/2 and 1 disappears,decreases with the increase of the three-body interaction,while the threshold temperature of the case of two spin 1/2 remains unchanged with the increase of the three-body interaction.When the temperature is near the absolute zero,the sudden change of both entanglement with three-body interaction can reflect the abrupt change for the ground state of system.For mixed spin(1,1/2,1)system,the threshold temperature for the spin 1 and 1/2 decreases with the increase of three-body interaction,while the threshold temperature for the entanglement between two 1 spin increases with the increase of three body interaction.Only the entanglement between the two lattice points of spin 1 and 1/2 can reflect the abrupt change of ground state of the system.In these two mixed spin systems,the principle of monogamy of entanglement can be found.