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arXiv 0912.4469cond-mat.dis-nncond-mat.supr-con
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Hopfield费米子伊辛自旋玻璃中的逆冻结

Inverse freezing in the Hopfield Fermionic Ising Spin Glass

S. G. Magalhaes, C. V. Morais, F. M. Zimmer

摘要:

在这项工作中,它是研究的Hopfield费米子自旋玻璃模型,它允许从平凡的随机性插入到一个高度受挫制度。因此,它是可能的调查是否挫折是一个必不可少的成分,这将允许该磁无序模型,通过比较两个限制,平凡的随机性和高度挫折制度,以及如何不同程度的挫折可能会影响这种非常规的相变,自然呈现逆冻结。这个问题是表示在路径积分形式主义的自旋算子表示的格拉斯曼变量的双线性组合。在静态近似和一步复本对称性破缺方案下得到了巨正则势。结果,获得了几个阻挫水平的相图温度{ \it vs}化学势。特别地,当挫折的水平降低时,与逆冻结相关的再进入被逐渐抑制。

英文摘要:

In this work it is studied the Hopfield fermionic spin glass model which allows interpolating from trivial randomness to a highly frustrated regime. Therefore, it is possible to investigate whether or not frustration is an essential ingredient which would allow this magnetic disordered model to present naturally inverse freezing by comparing the two limits, trivial randomness and highly frustrated regime and how different levels of frustration could affect such unconventional phase transition. The problem is expressed in the path integral formalism where the spin operators are represented by bilinear combinations of Grassmann variables. The Grand Canonical Potential is obtained within the static approximation and one-step replica symmetry breaking scheme. As a result, phase diagrams temperature {\it versus} the chemical potential are obtained for several levels of frustration. Particularly, when the level of frustration is diminished, the reentrance related to the inverse freezing is gradually suppressed.

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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