Dynamica phase transitions in the 2D XY model

Abstract

Thesis (B.S.)--University of Rochester. Dept. of Physics and Astronomy, 1990.The 2D XY model is studied by Monte Carlo simulations in which two different configurations, subjected to the same thermal noise, are compared. By using a Rotationally Invariant Dynamics, we observe only two temperature regimes: a high-temperature phase where the two configurations are random with respect to each other and a low-temperature phase where the spins in each configuration tend to align in certain direction. This contrasts with the three phases reported recently in a work by Golinelli and Derrida. We also find that our transition temperature is close to the Kosterlitz-Thouless transition temperature