Dynamic Coarse-Graining and Memory Effects in Soft Matter Systems
- Gerhard Jung (Institute of Physics - Johannes Gutenberg-Universität Mainz, Germany)
- Dominika Lesnicki (Institute of Physics - Johannes Gutenberg-Universität Mainz, Germany)
Whether we consider small or large molecules, nanoparticles or colloids, all objects suspended in a fluid evolve in
conjunction with this fluid. In general, we are only interested in the dynamics of these molecules and not in the details
of the fluid flow. Therefore, we describe the effect of the fluid only implicitly, through friction and random forces.
The Brownian movement model, introduced by Einstein more than a century ago, applies well when the objects in
question relax very slowly in relation to their environment. Or, in other words, if a time scale separation between
the dynamics of the large molecules and the fluid can be assumed. However, in general, the effect of the fluid is not
instantaneous [1, 2]. The movement of the molecules in the fluid will induce a disturbance of the flow field that affects
the movement of other molecules or themselves. The latter is also known as the hydrodynamic backflow effect and
usually described by a frequency-dependent friction term in the equations of motion for the solute . One prominent
consequence of this “memory effect” is the slow (algebraic) decrease in certain properties, such as the velocity auto-
correlation function . This is only one of many examples in soft matter physics, where frequency-dependent
phenomena and memory effects can be observed [4–7].
In the present workshop, we address the general problem of dynamic coarse-graining in situations where the sep-
aration of time scales is incomplete. This includes the general analysis of frequency-dependent phenomena in soft
matter systems using experiments, theory or computer simulations [4, 8, 9], as well as the detailed discussion of
methods that can be used for systematic dynamic coarse-graining [10–18].
The purpose of this workshop is to bring together scientists with very different background that work or have worked on non-Markovian dynamics and dynamic coarse-graining. Since the community in this special area of research is still very small, we hope, that the workshop can stimulate discussions and ideas for future research topics. The need of advanced theoretical understanding and coarse-graining techniques is especially important due to the emerging fields of active particles and nonequilibrium statistical physics.
The workshop takes place in Mainz, Germany, where two large condensed matter groups are located: The condensed matter research group at University of Mainz, Komet1/2, headed by Prof. Friederike Schmid and the theory group of MPIP, headed by Prof. Kurt Kremer. This event is organized in the scope of our research project SFB TRR146 (https://trr146.de) of the German Science Foundation about "Multiscale Simulation Methods for Soft Matter Systems".
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