On the microscopic foundation of dissipative particle dynamics

TL;DR

This paper investigates whether a Voronoi-based coarse-graining method can reliably derive mesoscopic dissipative particle dynamics from microscopic fluids, finding it inadequate for capturing meaningful physical properties.

Contribution

The study critically evaluates a proposed Voronoi projection method for microscopic to mesoscopic coarse-graining, revealing its limitations in preserving physical properties.

Findings

Voronoi projection fails to produce meaningful coarse-grained particles.

The method yields identical equilibrium properties for different microscopic systems.

The approach does not reliably connect microscopic and mesoscopic scales.

Abstract

Mesoscopic particle based fluid models, such as dissipative particle dynamics, are usually assumed to be coarse-grained representations of an underlying microscopic fluid. A fundamental question is whether there exists a map from microscopic particles in these systems to the corresponding coarse-grained particles, such that the coarse-grained system has the same bulk and transport properties as the underlying system. In this letter, we investigate the coarse-graining of microscopic fluids using a Voronoi type projection that has been suggested in several studies. The simulations show that the projection fails in defining coarse-grained particles that have a physically meaningful connection to the microscopic fluid. In particular, the Voronoi projection produces identical coarse-grained equilibrium properties when applied to systems with different microscopic interactions and different bulk properties.