发表机构
Harvey Mudd College; University of California, Davis（哈维穆德学院; 加州大学戴维斯分校）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过蒙特卡洛模拟发现，局域高斯无序降低铁磁Blume-Capel模型的临界温度，并抑制甚至消除一级相变，但临界温度在强无序下仍保持有限。
AI 中文摘要
我们对Blume-Capel模型的一种推广进行了数值研究，其中控制局域空位密度的晶体场$D_i$是依赖于位置的，而非均匀的。我们采用马尔可夫链蒙特卡洛方法，在固定$\bar{D}$的情况下，计算了移位相变线$T_c$作为高斯分布$P(D_i) \sim \exp( -(D_i - \bar{D})^2/2 \sigma^2)$宽度$\sigma$的函数。我们描述了这种局域高斯无序的存在如何沿二级相变线降低$T_c$，并讨论了我们的结果如何表明即使在$\sigma$较大时$T_c$仍保持有限。我们还确定了无序对传统均匀Blume-Capel模型三相点的影响，发现无序显著抑制了一级相变，在$\sigma$较大时完全消除了该相变。
英文摘要
We conduct a numerical study of a generalization of the Blume-Capel model in which the crystal field $D_i$, which controls the local vacancy density, is site dependent rather than uniform. We employ Markov Chain Monte Carlo to compute the shifted phase transition line $T_c$ as a function of the width $σ$ of a gaussian distribution $P(D_i) \sim \exp( -(D_i - \bar{D})^2/2 σ^2)$ at fixed $\bar{D}$. We characterize how the presence of this on-site Gaussian disorder reduces $T_c$ across the second order transition line, and discuss how our results suggest that $T_c$ remains finite even at large values of $σ$. We also determine the effects of disorder on the tricritical point of the conventional, uniform, Blume-Capel model, finding that it significantly suppresses the first-order phase transition, eliminating it entirely at large values of $σ$.
Comments8 pages, 10 figures
