Premium
Non‐equilibrium behaviour of equilibrium reservoirs in molecular simulations
Author(s) -
Tysanner Martin W.,
Garcia Alejandro L.
Publication year - 2005
Publication title -
international journal for numerical methods in fluids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.938
H-Index - 112
eISSN - 1097-0363
pISSN - 0271-2091
DOI - 10.1002/fld.983
Subject(s) - statistical physics , simple (philosophy) , momentum (technical analysis) , physics , artifact (error) , mechanics , classical mechanics , computer science , economics , philosophy , epistemology , finance , computer vision
Abstract We explore two widely used algorithms for fluid reservoirs in molecular simulations and demonstrate that they may induce non‐physical non‐equilibrium effects, even in systems that should be at equilibrium. For example, correlations of momentum and density fluctuations lead to a bias in the mean fluid velocity when measured as the mean over samples of instantaneous fluid velocity. The non‐physical behaviour is entirely computational in origin and is an instance of a more general issue in molecular simulations: a failure to correctly model stochastic properties may induce non‐equilibrium behaviour that does not exist in the corresponding physical system. Finally, we demonstrate that simple algorithm corrections eliminate this artifact. Copyright © 2005 John Wiley & Sons, Ltd.