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arXiv 0907.1474cond-mat.stat-mech
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全阻挫XY模型老化的数值研究

Numerical investigation of the aging of the Fully-Frustrated XY model

Jean-Charles Walter, Christophe Chatelain

摘要:

研究了完全阻挫XY模型的非平衡动力学。在平衡时,该模型在两个非常接近的温度下经历了两个相变:Kosterlitz无相变拓扑转变和顺磁相和低温相之间的二阶相变,其中晶格斑的手性是反铁磁有序的。我们通过蒙特卡罗模拟计算了两次自旋-自旋和手征-手征自相关函数和响应函数。从自旋波在低温相的动力学,我们提取的温度依赖的指数$η$。我们提供的Kosterlitz无温度以上的对数校正的证据,并解释它们作为一种表现形式的自由拓扑缺陷。我们对自相关指数和波动耗散比的估计与XY值不同,而$η(T_{\rm KT})$位于误差条的边界。在二阶临界温度的对数校正的指示。然而,角度和手性之间的耦合仍然很强,并解释了为什么自相关指数和波动耗散比远离伊辛值,似乎是稳定的。

英文摘要:

We study the out-of-equilibrium dynamics of the fully-frustrated XY model. At equilibrium, this model undergoes two phase transitions at two very close temperatures: a Kosterlitz-Thouless topological transition and a second-order phase transition between a paramagnetic phase and a low-temperature phase where the chiralities of the lattice plaquettes are anti-ferromagnetically ordered. We compute by Monte Carlo simulations two-time spin-spin and chirality-chirality autocorrelation and response functions. From the dynamics of the spin waves in the low temperature phase, we extract the temperature-dependent exponent $η$. We provide evidences for logarithmic corrections above the Kosterlitz-Thouless temperature and interpret them as a manifestation of free topological defects. Our estimates of the autocorrelation exponent and the fluctuation-dissipation ratio differ from the XY values, while $η(T_{\rm KT})$ lies at the boundary of the error bar. Indications for logarithmic corrections at the second-order critical temperature are presented. However, the coupling between angles and chiralities is still strong and explains why autocorrelation exponent and fluctuation-dissipation ratio are far from the Ising values and seems stable.

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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