Reduced probability densities of long-lived metastable states as those of distributed thermal systems: possible experimental implications for supercooled fluids
When liquids are cooled sufficiently rapidly below their melting temperature, they may bypass crystalization and, instead, enter a long-lived metastable supercooled state that has long been the focus of intense research. Although they exhibit strikingly different properties, both the (i) long-lived supercooled liquid state and (ii) truly equilibrated (i.e., conventional equilibrium fluid or crystalline) phases of the same material share an identical Hamiltonian. This suggests a mapping between dynamical and other observables in these two different arenas. We formalize these notions via a simple theorem and illustrate that given a Hamiltonian defining the dynamics: (1) the reduced probability densities of all possible stationary states are linear combinations of reduced probability densities associated with thermal equilibria at different temperatures, chemical potentials, etc. (2) Excusing special cases, amongst all of these stationary states, a clustering of correlations is only consistent with conventional thermal equilibrium states (associated with a sharp distribution of the above state variables). (3) Other stationary states may be modified so as to have local correlations. These deformations concomitantly lead to metastable (yet possibly very long-lived) states. Since the lifetime of the supercooled state is exceptionally long relative to the natural microscopic time scales, their reduced probability densities may be close to those that we find for exact stationary states (i.e., a weighted average of equilibrium probability densities at different state variables). This form suggests several new predictions such as the existence of dynamical heterogeneity stronger than probed for thus far and a relation between the specific heat peak and viscosities. Our theorem may further place constraints on the putative "ideal glass" phase.
Two-state thermodynamics of the ST2 model for supercooled water
ST 2模型的热力学性质的过冷液体水表现出类似于在真实的水观察到的异常。这些异常现象的一个可能的解释是存在一个亚稳态的，由临界点终止的液-液转变。这种现象，其可能存在于真实的水是目前许多实验工作的主题，已经明确地证明了这个特定的模型，最新的模拟。在这项工作中，我们再现了两个版本的ST 2模型的状态方程描述水作为一个非理想的“混合物”的两种不同类型的本地分子秩序的异常。我们表明，在ST 2水的液-液转变是能量驱动的。这与另一种流行的模型mW相反，在mW中，两种替代的局部分子顺序的混合的非理想性是熵驱动的，并且不足以强到诱导液-液转变。
Inferring intermediate states by leveraging the many-body Arrhenius law
The Institute of Mathematical Sciences（数学科学研究所）；Homi Bhabha National Institute（霍米·巴巴国立研究所）；University of Haifa at Oranim（奥拉尼姆海法大学）；University of Haifa（海法大学）
