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, across the bulk transition line, the Polyakov loop undergoes a discontinuous jump implying the existence of both confining and deconfining phases on its two sides. Implications for universality and the nature of the confining-deconfining transition are discussed.