Coarse-graining of microscopic dynamics into a mesoscopic transient potential model

Area of Science:

• * Computational physics and chemistry
• * Soft matter physics
• * Statistical mechanics

Background:

• * Developing accurate coarse-grained models is crucial for simulating large-scale complex systems.
• * Existing models often struggle to capture the transient dynamics of complex potentials.
• * Microscopic dynamics, like the Langevin equation, provide a foundation but are computationally expensive.

Purpose of the Study:

• * To derive a mesoscopic coarse-grained dynamics model from underlying microscopic dynamics.
• * To incorporate transient potentials into coarse-grained models for improved accuracy.
• * To develop a simplified yet effective model for simulating complex systems.

Main Methods:

• * Formal derivation from overdamped Langevin equation using path probability and Onsager-Machlup action.
• * Incorporation of transient potential to simplify mesoscopic degrees of freedom.
• * Introduction of auxiliary degrees of freedom for the transient potential state, creating a hybrid model.

Main Results:

• * Successfully derived the Langevin equation with transient potential (LETP) model.
• * The LETP model exhibits a dynamical structure similar to responsive particle dynamics and multichain slip-spring models.
• * Demonstrated the application of LETP to single-particle dynamics in supercooled liquids, showing good agreement with molecular dynamics simulations.

Conclusions:

• * The derived LETP model offers a computationally efficient and accurate approach for coarse-grained simulations.
• * This method provides a formal link between microscopic and mesoscopic descriptions of dynamics.
• * LETP is a promising tool for studying complex systems, particularly in supercooled liquids.