Wang-Landau Monte Carlo: A new key for unlocking structure in complex physical systems

The Wang-Landau technique is a new Monte Carlo approach which provides an effective means of studying the behaviour of a complex physical system over a wide temperature range. It facilitates the calculation of a system's heat capacity as a function of temperature, enabling transitions between stable phases to be identified. Combined with the calculation of properties such density, cluster size, number of discrete clusters, the evolution of the distribution of different structures across varying temperatures may be determined. We leverage the technique to identify structures representative of the system in each phase. Concrete examples are taken from studies of multiblock copolymers. The phase transitions found include transitions between polyglobular and entwined spiral structures, and the order-disorder transition between ordered striped (lamellar) and disordered random globule phases of the collapsed polymer.