Phase transition of a two-dimensional, multiplicatively coupled XY–Potts model

Date: 2009-05-08
Authors M. Hellmann, Y. Deng, M. Weiss and D. W. Heermann
Journal No. Journal of Physics A: Mathematical and Theoretical42, 225001 (2009)
Abstract We investigate the phase transition of a combination of a two-dimensional Potts and an XY model where the coupling is multiplicative. As the XY model has a Kosterlitz–Thouless transition and the Potts variable is constrained to three states (yielding a second order transition), the order of the phase transition and the universality class of the investigated combined model are far from obvious. We find that the transition is shifted to a lower critical temperature while the course of the internal energy is steeper compared to the two constituting models. Still, we find strong indications that the transition is continuous. Our model may serve as a coarse-grained description of surface-attached flexible polymers, e.g. in the context of the extracellular matrix of living cells.