  The repton model is a simple model of the "reptation" motion by which DNA
diffuses through a gel during electrophoresis. In this paper we show that the
model can be mapped onto a system consisting of two types of particles with
hard-sphere interactions diffusing on a one-dimensional lattice. Using this
mapping we formulate an efficient Monte Carlo algorithm for the model which
allows us to simulate systems more than twice the size of those studied before.
Our results confirm scaling hypotheses which have previously been put forward
for the model. We also show how the particle version of the model can be used
to construct a transfer matrix which allows us to solve exactly for the
diffusion constant of small repton systems. We give results for systems of up
to 20 reptons.
