FINITE-TEMPERATURE PHASE-TRANSITION IN SU(2) LATTICE GAUGE-THEORY WITH EXTENDED ACTION

We study the three dimensional fundamental-adjoint SU(2) lattice gauge theory at finite temperature by Monte Carlo simulations. We find that the finite-temperature deconfinement phase transition line joins the first-order bulk phase transition line at its endpoint. Moreover, acro ss the bulk transition line, the Polyakov loop undergoes a discontinuo us jump implying the existence of both confining and deconfining phase s on its two sides. Implications for universality and the nature of th e confining-deconfining transition are discussed.