AI 中文总结
研究正则涨落诊断在埃伦费斯特分类中一阶、二阶和三阶相变中的表现，考虑八态Potts模型等系统，发现基于涨落的可观测量在不同热力学区域有不同响应形态，反映对潜在相变性质的敏感性而非埃伦费斯特阶分类。
AI 中文摘要
微正则拐点分析从微正则熵的导数中识别出MIPA型高阶转变结构。然而，直到最近，还没有一种正则公式可以直接从可测量的能量涨落中探测相应的涨落水平行为，而无需重构态密度。先前的工作通过引入一种量化能量涨落不对称性的正则涨落诊断来解决这一限制。在此，我们研究了这种诊断在埃伦费斯特分类中具有代表性的一阶、二阶和三阶相变中的表现。我们考虑了八态Potts模型、二维Ising模型和理想三维玻色 - 爱因斯坦凝聚。Potts和Ising系统在各自的转变区域附近表现出诊断的稳健配对极值结构，而理想玻色 - 爱因斯坦凝聚在热力学极限下在凝聚温度处表现出不连续响应。这些结果表明，一个基于涨落的可观测量在不同的热力学区域可以显示出定性不同的响应形态，反映了对潜在相变性质的敏感性，而不是作为埃伦费斯特阶的直接分类器。
英文摘要
Microcanonical inflection-point analysis identifies MIPA-type higher-order transition structures from derivatives of the microcanonical entropy. Until recently, however, there was no canonical formulation for probing the corresponding fluctuation-level behavior directly from measurable energy fluctuations without reconstructing the density of states. Previous work addressed this limitation by introducing a canonical fluctuation diagnostic that quantifies energy-fluctuation asymmetry. Here, we investigate how this diagnostic behaves across representative first-, second-, and third-order phase transitions in the Ehrenfest classification. We consider the eight-state Potts model, the two-dimensional Ising model, and ideal three-dimensional Bose--Einstein condensation. The Potts and Ising systems exhibit a robust paired-extremum structure of the diagnostic near their respective transition regions, whereas ideal Bose--Einstein condensation exhibits a discontinuous response at the condensation temperature in the thermodynamic limit. These results show that a single fluctuation-based observable can display qualitatively distinct response morphologies across thermodynamic regimes, reflecting sensitivity to the nature of the underlying phase transition rather than serving as a direct classifier of Ehrenfest order.
Comments12 pages, 4 figures
