We study topological defects in the triangular Ising antiferromagnet, a related model on the square lattice equivalent to the six-vertex ice model, and the three-state antiferromagnetic Potts model on the square lattice. We suggest that in each case, defects are attracted or repelled with a...

We study the average time necessary for two independent random walkers to cover a periodic one-dimensional lattice completely, as function of the lattice size and the starting positions of the walkers.

We examine the sources of error in the histogram reweighting method for Monte Carlo data analysis. We demonstrate that, in addition to the standard statistical error which has been studied elsewhere, there are two other sources of error, one arising through correlations in the reweighted...

Using a nonlinear projection operator technique, the Markovian stochastic dynamics of a classical Brownian particle is derived in the case that the effective temperature is not constant. After recapitulating the general formalism and its application to isothermal Brownian motion, an isolated...

We introduce three models of fragmentation in which the largest fragment in the system can be broken at each time step with a fixed probability, p. We solve these models exactly in the long time limit to reveal stable time-invariant (scaling) solutions which depend on p and the precise details...

We introduce a new model for the interaction of immunological cells that takes into account their location in real space. Each one of the model cells mimics the real B cells in the sense that they detect antigens and they are also capable of reproducing themselves. We perform computer...