不对称外磁场下两量子比特系统的几何相

发布时间：2018-08-12 18:24

【摘要】：研究了不对称旋转外磁场下具有XXZ型海森堡相互作用的两量子比特系统的几何相。考虑体系的绝热条件,利用数值模拟的方法得到量子比特系统的4个本征态的Berry相,研究了外加旋转磁场的极角以及量子比特之间相互作用的各向异性参数对4个本征态的Berry相的影响。研究结果表明:当极角保持不变,各向异性参数由0增加至无穷大的过程中,系统的哈密顿量由一种极限下的含外场的XX模型经过中间的海森堡模型,逐渐演化为另外一种极限下的Ising模型。4个本征态的Berry相都有各自独特的变化规律,且极角越小几何相趋于稳定越快。通过对系统Berry相的研究,可以得到系统在不同参数区间对应的模型的转化,并对本征态的几何性质有更进一步的认识。
[Abstract]:The geometric phase of two quantum bit systems with XXZ type Heisenberg interaction in an asymmetric rotating external magnetic field is studied. Considering the adiabatic condition of the system, the Berry phases of the four intrinsic states of the quantum bit system are obtained by numerical simulation. The effects of the polar angle of the external rotating magnetic field and the anisotropic parameters of the quantum bit interaction on the Berry phases of the four intrinsic states are investigated. The results show that when the pole angle remains constant and the anisotropic parameter increases from 0 to infinity, the Hamiltonian of the system passes through the intermediate Heisenberg model from the XX model with an external field at the limit. The Berry phases of each of the four eigenstates have their own unique laws, and the smaller the polar angle, the more stable the geometric phase is. Through the study of the Berry phase of the system, we can get the transformation of the model corresponding to the system in different parameter intervals, and have a further understanding of the geometric properties of the intrinsic states.
【作者单位】：西安工程大学理学院;西安交通大学理学院;中航光电科技股份有限公司光电设备事业部;
【基金】：国家自然科学基金项目(11504283) 中国博士后基金面上项目(2014M562385) 西安交通大学基本科研业务费自由探索与自主创新类项目(xjj2014006)
【分类号】：O413

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