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.
Kobayashi, H., Rohrbach, P. B., Scheichl, R., Wilding, N. B., & Jack, R. L. (2019). Correction of coarse-graining errors by a two-level method: Application to the Asakura-Oosawa model. Journal of Chemical Physics, 151(14), [144108 (2019)]. https://doi.org/10.1063/1.5120833