非均匀磁场和杂质磁场对自旋1系统量子关联的影响

Effects of inhomogeneous magnetic field and magnetic impurity on the quantum correlation of spin-1 system

通过负值度和测量诱导的扰动,研究了非均匀磁场和杂质磁场对自旋为1的Heisenberg系统量子关联的影响.研究发现非均匀磁场的增加会降低纠缠,但也可用来产生纠缠,并且会提高临界非线性作用Kc的值,测量诱导的扰动的临界磁场要高于负值度的临界磁场,而且测量诱导的扰动不会随着非线性作用|K|的减小而消失,它能全面反映量子关联的存在.研究还发现,不同杂质磁场对测量诱导的扰动的影响彼此间无交叉.杂质磁场下,相互作用|J|必须小于非线性作用|K|才会有纠缠存在,但是测量诱导的扰动却可以在相互作用|J|大于非线性作用|K|时依然存在,|J|与|K|相同时只是测量诱导的扰动的最小取值点.此外,系统粒子数目对量子关联也具有重要影响.

We investigate the effects of inhomogeneous magnetic field and magnetic impurity on the quantum correlation in spin-1 system by means of negativity and measurement-induced disturbance. Results show that the increase of the inhomogeneous magnetic field not only decreases entanglement, but also can induce the entanglement, and increases the value of critical nonlinear coupling Kc. The critical magnetic field for measurement-induced disturbance is higher than that for negativity, and the measurement-induced disturbance（MID） will not disappear with the decrease of nonlinear coupling ｜K｜, so it can reveal all the properties of quantum correlation. Results also show that the effects of different magnetic impurity on MID are independent of each other. Under the magnetic impurity, the entanglement exists only if the couplings ｜J｜ are less than the nonlinear couplings ｜K｜, while there will be the MID when the couplings ｜J｜ are greater than the nonlinear couplings ｜K｜. It is just the minimum point for MID when ｜J｜ equals to ｜K｜. Moreover, the size of the Chain will influence the quantum correlation also.