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Dynamic coarse-graining of linear and non-linear systems: Mori–Zwanzig formalism and beyond.

Authors :
Jung, Bernd
Jung, Gerhard
Source :
Journal of Chemical Physics. 8/28/2023, Vol. 159 Issue 8, p1-17. 17p.
Publication Year :
2023

Abstract

To investigate the impact of non-linear interactions on dynamic coarse graining, we study a simplified model system featuring a tracer particle in a complex environment. Using a projection operator formalism and computer simulations, we systematically derive generalized Langevin equations (GLEs) describing the dynamics of this particle. We compare different kinds of linear and non-linear coarse-graining procedures to understand how non-linearities enter reconstructed GLEs and how they influence the coarse-grained dynamics. For non-linear external potentials, we show analytically and numerically that the non-Gaussian parameter and the incoherent intermediate scattering function will not be correctly reproduced by the GLE if a linear projection is applied. This, however, can be overcome by using non-linear projection operators. We also study anharmonic coupling between the tracer and the environment and demonstrate that the reconstructed memory kernel develops an additional trap-dependent contribution. Our study highlights some open challenges and possible solutions in dynamic coarse graining. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
00219606
Volume :
159
Issue :
8
Database :
Academic Search Index
Journal :
Journal of Chemical Physics
Publication Type :
Academic Journal
Accession number :
171316917
Full Text :
https://doi.org/10.1063/5.0165541