Comments on “Advantages and challenges in coupling an ideal gas to atomistic models in adaptive resolution simulations” by K. Kreis, A.C. Fogarty, K. Kremer and R. Potestio

Abstract

This paper describes the first successful steps towards the goal of minimizing the complexity of the coarse-grained (CG) part of adaptive resolution molecular dynamics(MD) simulations. The idea is motivated by the observation that in such simulations, when they aim at generating proper statistics in the atomistic resolution region, i.e., when they don't need to be dynamically accurate, the coarse-grained region is just there to provide an appropriate thermodynamic bath. In addition, the detailed behavior of particles passing into the atomistic region can still be manipulated considerably while they are passing the hybrid region. Thus, the authors ask why one should not use the simplest particle model available in the coarse-grained region, set up such that it provides the minimal statistical information needed to reliably drive the statistics in the atomistic subdomain. In a first realization of this approach, they adopt an ideal gas model that is void of any particle-particle interactions in the coarse-grained region, they discuss some subtleties that need attention to make it all work, and demonstrate convincing performance and reasonable to very good accuracy of this extreme variant of adaptive resolution modelling.