arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0812.4750cond-mat.str-elcond-mat.stat-mech
收藏

Jordan-Wigner费米化和低维量子自旋模型理论。动力特性

Jordan-Wigner Fermionization and the Theory of Low-Dimensional Quantum Spin Models. Dynamic Properties

Oleg Derzhko

摘要:

Jordan-Wigner变换是凝聚态理论中的一个强有力的工具,特别是在低维量子自旋系统的理论中。本章的目的是回顾乔丹-维格纳费米子化技术在计算低维量子自旋模型的动力学量中的应用。在简要介绍了一维自旋二分之一系统的Jordan-Wigner变换及其在高维和高自旋情况下的一些推广之后,我们着重讨论了几种低维量子自旋模型的动力学性质。我们从著名的s=1/2 XX链开始。作为第一步,我们回顾众所周知的结果的z-自旋分量波动算子的动力学,然后转向二聚体和三聚体波动算子的动力学。三聚体涨落的动力学涉及两个费米子(一个粒子和一个空穴)和四个费米子(两个粒子和两个空穴)激发。本文讨论了两费米子和四费米子激发连续统的一些性质。四费米子动力学量的复杂性介于简单的两费米子(如zz动态结构因子)和非常复杂的多费米子(如xx或xy动态结构因子)动力学量之间。此外,我们讨论了二聚化,XY相互作用的各向异性,以及额外的Dzyaloshinskiii-Moriya相互作用对各种动力学量的影响。最后,我们考虑的动态横向自旋结构因子$S_{zz}({\bf{k}},ω)$的s=1/2 XX模型上的空间各向异性的正方形晶格,它允许一个跟踪一个到二维的动态量的交叉。

英文摘要:

The Jordan-Wigner transformation is known as a powerful tool in condensed matter theory, especially in the theory of low-dimensional quantum spin systems. The aim of this chapter is to review the application of the Jordan-Wigner fermionization technique for calculating dynamic quantities of low-dimensional quantum spin models. After a brief introduction of the Jordan-Wigner transformation for one-dimensional spin one-half systems and some of its extensions for higher dimensions and higher spin values we focus on the dynamic properties of several low-dimensional quantum spin models. We start from the famous s=1/2 XX chain. As a first step we recall well-known results for dynamics of the z-spin-component fluctuation operator and then turn to the dynamics of the dimer and trimer fluctuation operators. The dynamics of the trimer fluctuations involves both the two-fermion (one particle and one hole) and the four-fermion (two particles and two holes) excitations. We discuss some properties of the two-fermion and four-fermion excitation continua. The four-fermion dynamic quantities are of intermediate complexity between simple two-fermion (like the zz dynamic structure factor) and enormously complex multi-fermion (like the xx or xy dynamic structure factors) dynamic quantities. Further we discuss the effects of dimerization, anisotropy of XY interaction, and additional Dzyaloshinskii-Moriya interaction on various dynamic quantities. Finally we consider the dynamic transverse spin structure factor $S_{zz}({\bf{k}},ω)$ for the s=1/2 XX model on a spatially anisotropic square lattice which allows one to trace a one-to-two-dimensional crossover in dynamic quantities.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑