This article reviews, from a very personal point of view, the origins and the early work on
transitions driven by topological defects such as vortices in the two dimensional planar rotor …

We discuss the nature and sequence of phase transitions in two-dimensional systems with
continuous degeneracy, in which other factors must be taken into account in addition to the …

We present details of a stochastic generalization of the multigrid method, called multigrid
Monte Carlo (MGMC), that reduces critical slowing down in Monte Carlo computations of …

The extended Hubbard model in one dimension is studied for half-filled bands using a
continuum theory based on the Luttinger model. Interactions going beyond the Luttinger …

Renormalization-group analysis is employed to investigate the critical behavior of coupled
XY models. Recursion relations for small vortex fugacities and Migdal recursion relations in …

We study the critical behavior of fully frustrated XY and Josephson-junction systems by
means of a coupled XY-Ising model. From Monte Carlo and transfer-matrix calculations, we …

We investigate the nature of phase transitions in a generalized uniformly frustrated square-
lattice model with XY spins. The frustration is made to vary by changing the negative bond …

The nonequilibrium relaxation (NER) method is a numerical technique to analyse
equilibrium phase transitions. One can estimate the transition point and critical exponents …

The critical behavior of the fully frustrated XY model on a triangular and square lattice is
investigated by Monte Carlo simulations. From a finite-size-scaling analysis we determine …

A simple model for weak quenched disorder in Josephson-junction arrays is considered and
the effects of two kinds of disorder on the resistive behavior of the array is determined. For …