de Souza Wescley Luiz, de Mello Silva Érica, Martins Paulo H L
Instituto de Educação, Ciência e Tecnologia de Mato Grosso-Campus Cuiabá Rua Professora Zulmira Canavarros, 95, 78005-200 Cuiabá, MT, Brazil.
Universidade Federal de Mato Grosso, Instituto de Física, Av. Fernando Corrêa da Costa, 2367, Bloco F, 78060-900 Cuiabá, MT, Brazil.
Phys Rev E. 2020 Apr;101(4-1):042104. doi: 10.1103/PhysRevE.101.042104.
Multiple-spin coupling is a key tool for investigating magnetic quantum systems. In particular, models with four-spin interactions became of great interest since they have been applied to describe material properties such as superconductivity. In this framework, the dynamics of the spin-1/2 Ising two-leg ladder with four-spin plaquette interaction in a transverse field is investigated. By means of the recurrence relations method, the first four recurrants are determined exactly for the general model, while five exact recurrants are calculated for two particular models. In all cases, higher-order recurrants are computed through extrapolation to obtain time-dependent autocorrelation functions and spectral densities in the long-time regime and infinite-temperature limit. It is found that the relaxation functions decay slower than the expected behavior of the one-dimensional transverse Ising model. The spectral lines, characterized by a Lorentzian behavior in the central body and a Gaussian shape in the tails, display exchange narrowing as the coupling intensities increase.
多自旋耦合是研究磁量子系统的关键工具。特别是，具有四自旋相互作用的模型引起了极大的兴趣，因为它们已被用于描述诸如超导性等材料特性。在此框架下，研究了在横向场中具有四自旋格子相互作用的自旋-1/2伊辛两腿梯子的动力学。通过递推关系方法，对于一般模型精确确定了前四个递推量，而对于两个特定模型计算了五个精确递推量。在所有情况下，通过外推计算高阶递推量，以获得长时间区域和无限温度极限下的时间相关自相关函数和谱密度。结果发现，弛豫函数的衰减比一维横向伊辛模型的预期行为要慢。谱线在中心部分表现为洛伦兹行为，在尾部表现为高斯形状，随着耦合强度的增加呈现出交换窄化现象。
