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arXiv 1403.0979cond-mat.dis-nncond-mat.stat-mech
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无标度网络上自旋玻璃模型的逆跃迁

Inverse transitions in a spin-glass model on a scale-free network

Do-Hyun Kim

摘要:

在本文中,我们将通过考虑无标度网络上的自旋玻璃模型来研究临界现象。为此,我们考虑Ghatak-Sherrington(GS)模型,一个自旋为1的自旋玻璃模型与晶体场,而不是通常的伊辛型模型。GS模型放置在其上的无标度网络是从静态模型构造的,其中顶点的数量从一开始就固定。在复制对称解的基础上,我们得到了解析解,自由能和序参量,我们推导出各种相图组成的顺磁,铁磁,自旋玻璃相的温度$T$的函数,度指数$λ$,平均度$K$,和铁磁相互作用的分数$ρ$。由于本模型基于考虑三种状态($S=0, \pm 1$)的GS模型,因此$S=0$状态在$λ$依赖的临界行为中起着至关重要的作用:玻璃化转变温度$T_{g}$具有有限值,即使当$2 < λ< 3$ .此外,当晶体场变为非零时,本模型清楚地表现出三种类型的逆跃迁,这发生在有序相比无序相熵更大时。

英文摘要:

In this paper, we will investigate critical phenomena by considering a model spin-glass on scale-free networks. For this purpose, we consider the Ghatak-Sherrington (GS) model, a spin-1 spin-glass model with a crystal field, instead of the usual Ising-type model. Scale-free networks on which the GS model is placed are constructed from the static model, in which the number of vertices is fixed from the beginning. On the basis of the replica-symmetric solution, we obtain the analytical solutions, i.e., free energy and order parameters, and we derive the various phase diagrams consisting of the paramagnetic, ferromagnetic, and spin glass phases as functions of temperature $T$, the degree exponent $λ$, the mean degree $K$, and the fraction of the ferromagnetic interactions $ρ$. Since the present model is based on the GS model, which considers the three states ($S=0, \pm 1$), the $S=0$ state plays a crucial role in the $λ$-dependent critical behavior: glass transition temperature $T_{g}$ has a finite value, even when $2 < λ< 3$. In addition, when the crystal field becomes nonzero, the present model clearly exhibits three types of inverse transitions, which occur when an ordered phase is more entropic than a disordered one.

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。

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