Nature is intrinsically multiscale, with physical length scales ranging from the Planck length to planetary scales. Condensed matter is an important but challenging system for implementing a multiscale approach since the properties arising from chemical or physical changes take place on the femtoscale to exascale. This talk presents statistical mechanical paradigms for developing theoretical and computational methodologies to study complex condensed matter across multiple length and time scales. Systematic bottom-up coarse-graining (CG) of molecular systems provides the means to explore multiscale processes by treating the molecular-scale physics at a reduced level.

In order to faithfully develop coarse-grained models of molecular soft matter, this talk will approach the multiscale challenge from two first-principles-based perspectives: structure and dynamics. While the many-body correlations at the finer molecular level are often lost upon simplifying to a CG resolution, these structural correlations can be captured by designing a many-body CG potential of mean force for the CG variables with high transferability. In addition, CG dynamics are often incorrect due to missing fluctuation and frictional forces but can be rigorously understood by explicitly incorporating the missing forces or implicitly utilizing the excess entropy scaling. Altogether, our findings demonstrate that rigorous, physics-driven CG modeling can facilitate the efficient simulation of complex molecular soft matter and can help guide the future era of multiscale modeling.

Jaehyeok Jin is currently an Arnold O. Beckman Postdoctoral Fellow in Chemical Sciences with Professor David R. Reichman at Columbia University (USA). He received a Ph.D. in Chemistry in 2021 from the University of Chicago (USA), where he was a William Rainey Harper Dissertation Fellow under the supervision of Professor Gregory A. Voth.

His research interests lie in the development of predictive bottom-up multiscale theory for molecular soft matter using equilibrium and non-equilibrium statistical mechanics. He is also broadly interested in studies of soft condensed matter and active matter.