DECONFINEMENT TRANSITION AND DIMENSIONAL CROSS-OVER IN THE 3D GAUGE ISING-MODEL

We present a high-precision Monte Carlo study of the finite-temperatur e Z(2) gauge theory in 2 + 1 dimensions, The duality with the 3D Ising spin model allows us to use powerful cluster algorithms for the simul ations. For temporal extensions of up to N-t = 16 we obtain the invers e critical temperature with a statistical accuracy comparable with the most accurate results for the bulk phase transition of the 3D Ising m odel. We discuss the predictions of T.W. Capehart and M.E. Fisher for the dimensional cross-over from 2 to 3 dimensions. Our precise data fo r the critical exponents and critical amplitudes confirm the Svetitsky -Yaffe conjecture. We find deviations from Olesen's prediction for the critical temperature of about 20%.