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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 46: Poster II
CPP 46.60: Poster
Donnerstag, 12. März 2026, 09:30–11:30, P5
Density of states in monodisperse and polydisperse hard disks: Concentration dependent SAMC estimation — •Viktor Ivanov, Joram Heimbold, Malte Kautzsch, and Timur Shakirov — Martin-Luther-University Halle-Wittenberg, Halle (Saale), Germany
We propose a new variant of flat-histogram Monte Carlo, where the density of particles is the control parameter for the density of states and the visiting histogram. We simulate a system of point particles with zero diameter. The square of the minimal interparticle distance, rmin2, is used as the control parameter for a macrostate. The density of states and the visiting histogram depend on rmin2 and are updated at each step of the algorithm according to the usual SAMC rules. For a microstate (particilar configuration of particles) with a given value of the minimal distance between particles rmin one can replace the points with the hard disks of the diameter rmin or smaller, which corresponds to a system with a specific particle density. We apply this algorithm to 2d systems of monodisperse and polydisperse hard disks (with diameter distributions 1/d2) and study the density driven crystallization transition. For monodisperse hard disks the transition from the liquid to the hexatic phase proceeds via a first-order like pseudo-phase transition, whereas the transition from the hexatic to the crystalline phase is continuous. With increasing polydispersity, crystallization is significantly suppressed, such that no transition to the crystalline phase is observed for a 10% variation in particle radii.
Keywords: crystallisation of hard disks; hard disk glasses; flat-histogram Monte Carlo simulations