Nunes Maria Eugênia Silva, Plascak J A
Departamento de Física, ICEB, Universidade Federal de Ouro Preto, Campus Universitário Morro do Cruzeiro, 35400-000 Ouro Preto, MG, Brazil.
Centro de Desnvolvimento da Tecnologia Nuclear, C.P. 941, 30161-970 Belo Horizonte, MG, Brazil.
Phys Rev E. 2024 Jan;109(1-1):014134. doi: 10.1103/PhysRevE.109.014134.
The quantum spin-1/2 Ising ladder with homogeneous side rail interaction and disordered rung interaction in the presence of a random site transverse magnetic field has been studied using the method of recurrence relations in the high-temperature limit. The first six recurrants have been exactly calculated, and a linear extrapolation process has been used to obtain a total of 100 recurrants. This extrapolation allows us to extend the analysis to longer times. Both the rung coupling and the transverse field obey a bimodal distribution. The time autocorrelation functions of the z-component dynamic spin variable have been obtained. We have considered several cases of rung and transverse field distributions, as well as several values of the Hamiltonian parameters. The results show that the disorder present in the rung interaction and external transverse field affects the behavior of the temporal autocorrelation and the spectral functions in all studied cases. In addition, the interesting case where the rung interactions and the transverse magnetic field are correlated has also been studied. In general, transition in the dynamics of the system from individual to collective mode was observed depending on the dominant kind of interaction in the sites, that is, whether most of the sites were subject to a strong external field or strong interchain local interactions.
利用递推关系方法，在高温极限下研究了具有均匀侧链相互作用和无序梯级相互作用且存在随机格点横向磁场的量子自旋 - 1/2伊辛梯子。已精确计算出前六个递推项，并采用线性外推过程总共获得了100个递推项。这种外推使我们能够将分析扩展到更长时间。梯级耦合和横向场均服从双峰分布。已获得z分量动态自旋变量的时间自相关函数。我们考虑了梯级和横向场分布的几种情况以及哈密顿量参数的几个值。结果表明，梯级相互作用和外部横向场中存在的无序在所有研究情况下都会影响时间自相关和谱函数的行为。此外，还研究了梯级相互作用与横向磁场相关的有趣情况。一般来说，根据格点中主导的相互作用类型，即大多数格点是否受到强外部场或强链间局部相互作用，观察到了系统动力学从个体模式到集体模式的转变。
