Finite-temperature phase transition in SU(2) lattice gauge theory with extended action

Abstract

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.