Correction of coarse-graining errors by a two-level method: Application to the Asakura-Oosawa model

Abstract

We present a method that exploits self-consistent simulation of coarse-grained and fine-grained models, in order to analyse properties of physical systems. The method uses the coarse-grained model to obtain a first estimate of the quantity of interest, before computing a correction by analysing properties of the fine system. We illustrate the method by applying it to the Asakura-Oosawa (AO) model of colloid-polymer mixtures. We show that the liquid-vapour critical point in that system is affected by three-body interactions which are neglected in the corresponding coarse-grained model. We analyse the size of this effect and the nature of the three-body interactions. We also analyse the accuracy of the method, as a function of the associated computational effort. arXiv:1907.07912v1 [cond-mat.stat-mech]

Multi-body effects in a coarse-grained protein force field

“…29, 39, and 40). Multi-body terms have been added in CG models as a correction [41][42][43][44][45] or by considering the physical nature of the corresponding interactions, as for instance, water-mediated potentials. 20,46 However, the multi-body terms are often crucial to reproduce the system's behavior correctly.…”

Critical point for de-mixing of binary hard spheres

“…This work uses a two-level numerical method [25] to characterise the critical point for fluid-fluid phase separation in hard sphere mixtures. The first level of the method relies on an accurate coarse-grained (CG) model where the small particles are integrated out, providing an effective theory for the large ones.…”

“…This problem is avoided by the two-level method. We outline the approach, see [25] and Appendix A for details. The critical points of interest generically occur for parameters where the fluid phase is metastable with respect to crystallisation of the large particles [18] (recall Fig.…”

“…where R ij = |R i − R j | is the distance between particles i and j; also V 2 and V 3 are two-and three-body effective interactions, and the term N ∆µ ensures that the chemical potentials coincide between FG and CG models. The ∆µ, V 2 , V 3 are obtained by grand-canonical Monte Carlo (GCMC) simulation of small particles in systems which contain a few fixed large particles, see [25] and Appendix B.…”

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