  We study the thermodynamic and dynamic phase transitions in two-dimensional
polydisperse hard disks using Monte Carlo methods. A conventional local Monte
Carlo algorithm allows us to observe a dynamic liquid-glass transition at a
density, which depends very little on the degree of polydispersity. We
furthermore apply Monte Carlo methods which sample the Boltzmann equilibrium
distribution at any value of the density and polydispersity, and remain ergodic
even far within the glass. We find that the dynamical transition is not
accompanied by a thermodynamic transition in this two-dimensional system so
that the glass is thermodynamically identical to the liquid. Moreover, we
scrutinize the polydispersity-driven transition from the crystal into the
disordered phase (liquid or glass). Our results indicate the presence of a
continuous (Kosterlitz-Thouless type) transition upon increase of the
polydispersity.
