Effective potential for the order parameter of the SU(2) Yang-Mills deconfinement transition

The Polyakov loop variable serves as an order parameter to characterize the confined and deconfined phases of Yang-Mills theory. By integrating out the vector fields in the SU(2) Yang-Mills partition function in one-loop approximation, an effective action is obtained for the Polyakov loop to second order in a derivative expansion. The resulting effective potential for the Polyakov loop is capable of describing a second-order deconfinement transition as a function of temperature. Even at arbitrarily high temperatures, the standard high-temperature perturbative limit is never reached.