发表机构
Yukhnovskii Institute for Condensed Matter Physics of the National Academy of Sciences of Ukraine（乌克兰国家科学院尤赫诺夫斯基凝聚态物理研究所）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
研究具有Curie-Weiss相互作用的双占据单元流体模型，通过自旋-占据变量变换证明其与完全图上的Blume-Capel模型同构，并利用解析和数值方法揭示其丰富的相行为，包括单临界点、双临界点、三临界点和三相点。
AI 中文摘要
研究具有Curie-Weiss相互作用的双占据单元流体模型。首先，通过从自旋到占据变量的简单变换，证明该模型与完全图上的Blume-Capel模型同构。然后，结合解析和数值方法，在巨正则系综中研究其相行为。尽管模型简单，但根据局域排斥与全局吸引相互作用的比值，它表现出极其丰富的热力学行为。我们识别出具有单个临界点、两个不同临界点、三临界行为以及三相点形成的区域。当排斥足够强时，系统拥有三个不同密度的流体相，导致气-液和液-液共存。确定了临界点、三临界点和三相点的位置，并构建了相应的相图。这些结果表明，双占据排斥与长程吸引之间的竞争足以在最小多占据格子气模型中产生复杂的相行为。
英文摘要
A double-occupancy cell model of a fluid with Curie-Weiss interaction is studied. First, we show that the model is isomorphic to the Blume-Capel model on a complete graph through a simple transformation from spin to occupancy variables. We then investigate its phase behavior within the grand-canonical ensemble using a combination of analytical and numerical methods. Despite its simplicity, the model exhibits a remarkably rich thermodynamic behavior depending on the ratio between the local repulsive and global attractive interactions. We identify the regimes characterized by a single critical point, two distinct critical points, tricritical behavior, and triple-point formation. For sufficiently strong repulsion, the system possesses three fluid phases of different densities, leading to both gas-liquid and liquid-liquid coexistence. The locations of the critical, tricritical, and triple points are determined, and the corresponding phase diagrams are constructed. These results demonstrate that the competition between double-occupancy repulsion and long-range attraction is sufficient to generate a complex phase behavior in a minimal multiple-occupancy lattice-gas-like model.
Comments17 pages, 4 figures
Journal refCondens. Matter Phys. 2026, 29 (3), 33603
