Related Experiment Video
Updated: Jul 2, 2025

An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids
Published on: December 4, 2017
Microscopic Cutoff Dependence of an Entropic Force in Interface Propagation of Stochastic Order Parameter Dynamics
1Department of Physics, Kyoto University, Kyoto 606-8502, Japan.
Abstract:
The steady propagation of a (d-1)-dimensional planer interface in d-dimensional space is studied by analyzing mesoscopic nonconserved order parameter dynamics with two local minima under the influence of thermal noise. In this analysis, an entropic force generating interface propagation is formulated using a perturbation method. It is found that the entropic force singularly depends on an ultraviolet cutoff when d≥2. The theoretical calculation is confirmed by numerical simulations with d=2. The result means that an experimental measurement of the entropic force provides an estimation of the microscopic cutoff of the mesoscopic description.
Related Concept Videos
Entropy
Van der Waals Interactions
The Uncertainty Principle
Force and Potential Energy in One Dimension
Entropy and the Second Law of Thermodynamics
The relation between entropy and disorder can be illustrated with the example of the phase change of ice to water. In ice, the molecules are located at specific sites giving a solid state, whereas, in a liquid form, these molecules are much freer to move. The molecular arrangement has therefore become more randomized. Although the change in average...
The Second Law of Thermodynamics

