Statistical Mechanics and Phase Transitions

Michael Fisher由化学部理论和计算化学项目和材料研究部材料理论项目共同资助，继续他在统计力学、物质有序状态、状态间相变和临界现象方面的理论研究。将使用的方法包括热力学和标度分析、重整化群方法、蒙特卡罗模拟以及分析和数值技术。应用包括：1)研究发生库仑相分离的流体电解质，而不是疏溶剂相分离；2)研究二维硬核离子液体，它为表现出超流动性和超导电性的真实系统提供基本模型；3)表征临界终点附近的热力学行为，特别是在流体混合物中；4)研究壁面自由能和临界吸附的普遍方面。复杂分子体系的理论模型有助于理解和解释对这些体系的实验观察。它们提供了对复杂的分子相互作用的分子洞察，这些相互作用负责宏观行为和物理性质。这种洞察力通常也有助于优化具有所需性能的新材料的设计。

Michael Fisher is jointly supported by a grant from the Theoretical and Computational Chemistry Program in the Chemistry Division and the Materials Theory Program in the Division of Materials Research to continue his theoretical research in statistical mechanics, the study of ordered states of matter, phase transitions between states, and critical phenomena. The methodologies to be used include thermodynamic and scaling analyses, renormalization group methods, Monte Carlo simulations, and analytical and numerical techniques. Applications include: 1) investigations of fluid electrolytes that undergo Coulombic as opposed to solvophobic phase separation; 2) investigations of two-dimensional, hard core ionic fluids which provide a basic model for real systems exhibiting superfluidity and superconductivity; 3) the characterization of thermodynamic behavior near critical endpoints, particularly in fluid mixtures; 4) investigations of wall free energies and universal aspects of critical adsorption. Theoretical models of complex molecular systems are useful for understanding and interpreting experimental observations on these systems. They provide molecular insights into the complex molecular interactions that are responsible for macroscopic behavior and physical properties. Such insights are frequently also useful in optimizing the design of new materials having desired properties.