Critical fluctuations of QCD phase transitions and their related observables

Abstract

We study how the dilepton production rate and the electric conductivity are affected by the soft modes inherently associated with the second-order phase transitions at the critical temperature of color superconductivity and QCD critical point. It is shown that the soft modes modify the photon self-energy significantly through the so called Aslamasov-Larkin, Maki-Thompson and density of states terms, which are known responsible for the paraconductivity in the metallic superconductivity, and they lead to an anomalous enhancement of the production rate in the low energy/momemtum region and the divergence of conductivity at the critical temperature.