Should simulation-as a computer experiment- guide theory or the opposite? A liquid state physicist point of view

Aurelien Perera
Le laboratoire de Physique Théorique de la Matière Condensée de l'Université Pierre et Marie Curie, Paris


About a decade ago, computer simulations of complex liquids mixtures, such as water mixed with alcohols for example, posed seemingly formidable problems, that were predicted by many experts to be resolved in the future by the brute force increase of raw computational power. These problems were thought to be posed by the different force field representation of water and various solutes molecules as well as system sizes and length of statistics. It turned out that these problems were posed by a physical manifestation of these complex liquids, namely micro-heterogeneous distribution of species. This type of distribution poses fundamental problems about matter in general, principally about its homogeneity. The organiser of the Physics and Philosophy, Franjo Sokolic, and myself, were active actors in the change of paradigms that allowed to solve this problem at the modest level of the physics of liquids. The various steps of this exciting adventure are revisited, in connection to the many key concepts in Statistical Physics.