Confinement-Deconfinement Phase Transition in Hot and Dense QCD at Large N

We conjecture that the confinement deconfinement phase transition in QCD at large number of colors N and N-f << N at T not equal 0 and mu not equal 0 is triggered by the drastic change in theta behavior. The conjecture is motivated by the holographic model of QCD where confinement-deconfinement phase transition indeed happens precisely at T = T-c where theta dependence experiences a sudden change in behavior. The conjecture is also supported by quantum field theory arguments when the instanton calculations (which trigger the theta dependence) are under complete theoretical control for T > T-c, suddenly break clown immediately below T < T-c with sharp changes in the theta dependence. Finally, the conjecture is supported by a number of numerical lattice results. We employ this conjecture to study confinement-deconfinement phase transition of hot and dense QCD in large N limit by analyzing the theta dependence. We estimate the critical values for T-c and mu(c) where the phase transition happens by approaching the critical values from the hot and/or dense regions where the instanton calculations are under complete theoretical control. We also describe some defects of various codimensions within a holographic model of QCD by focusing on their role around the phase transition point.