Theory of Wavelet-Based Coarse-Graining Hierarchies for Molecular Dynamics

Report No. ARL-TR-7989
Authors: Berend Christopher Rinderspacher; Jaydeep P Bardhan; Ahmed E Ismail
Date/Pages: April 2017; 56 pages
Abstract: We present a multiresolution approach to compressing the degrees of freedom (DoFs) and potentials associated with molecular dynamics (MD). We suggest a systematic way to accelerate large-scale MD with more than 2 levels of coarse-graining, particularly for simulation of polymeric materials. We derive explicit models for linear polymers and iterative methods to compute large-scale wavelet decompositions from fragment solutions. This approach does not require explicit preparation of atomistic-to-coarse-grained (CG) mappings, but instead uses diffusion wavelets for graph Laplacians to develop system-specific mappings. Our methodology leads to a hierarchy of system-specific CG DoFs that provide a conceptually clear and rigorous framework for modeling chemical systems at relevant model scales. The approach is capable of automatically generating as many CG model scales as necessary, that is, to go beyond the 2 scales in conventional CG strategies. Furthermore, the wavelet-based CG models explicitly link time and length scales. Finally, a straightforward method to introduce omitted DoFs is presented, which plays a major role in maintaining model fidelity in long-time simulations and capturing emergent behaviors.
Distribution: Approved for public release
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Last Update / Reviewed: April 1, 2017