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DY: Fachverband Dynamik und Statistische Physik

DY 41: Modeling and Simulation of Soft Matter II (joint session CPP/DY)

DY 41.1: Hauptvortrag

Donnerstag, 4. April 2019, 09:30–10:00, H13

Systematic Dynamic Coarse-Graining with Memory — Gerhard Jung, Martin Hanke, and •Friederike Schmid — Johannes Gutenberg Universität Mainz, Germany

In soft matter, systematic coarse-graining (CG) approaches often face the problem that the separation of time scales is incomplete, and memory effects become important. One challenge is to extract the CG dynamical equations, namely the memory kernel, from equilibrium all-atom simulations. Another challenge is to devise an algorithm that efficiently deals with pair-memory contributions to the dynamical equations. Such pair-memory interactions may become important, e.g., in dispersions of nanocolloids when the frequency dependence of hydrodynamic interactions cannot be neglected.

The talk will address these two problems. We propose a "generalized Langevin Dynamics" model, which has the form of a generalized Langevin equation with distance-dependent two-particle contributions to the self- and pair-memory kernels. A simulation algorithm is developed that scales linearly with the number of coarse-grained particles. Furthermore, we present a robust iterative method for the accurate reconstruction of memory kernels from dynamic correlation functions.

We apply the method to a suspension of nanocolloids with frequency-dependent hydrodynamic interactions. The GLD simulations perfectly reproduce the dynamics of the underlying fine-grained system and accelerate the simulation by a factor of roughly 10.000.