Seoane, Beatriz

Title: Effective potential study of hard-spheres crystallization
Author: Beatriz Seoane
Affiliation: Universidad Complutense de Madrid, Spain
Abstract:
We use tethered Monte Carlo to study the fluid-solid phase transition in hard spheres at constant pressure. Tethered Monte Carlo features directly the effective potential by simulation of constrained statistical ensembles. In order to avoid metastabilities, we have found it crucial to constraint the values of two crystalline order parameters, namely Q_6 and C. Parameter Q_6 is the standard rotationally-invariant bond-ordering parameter and C is a variation of Q_6 which is only invariant with respect to the cubic group, thus allowing us to determine the alignment of the crystal planes. A sort of Maxwell construction yields the critical pressure and the densities of the coexisting phases. In the system sizes explored so far, up to N=864 particles, exponential critical slowing-down is not present. Note that state-of-the-art methods, such as phase-switch Monte Carlo, nowadays seem limited to N=500 due to strong exponential critical slowing-down.