Speed of sound and specific heat in the QCD plasma: hydrodynamics, fluctuations, and conformal symmetry

Abstract

We report the continuum limits of the speed of sound, C_s, and the specific heat at constant volume, C_V, in quenched QCD at temperatures of 2T_c and 3T_c. At these temperatures, C_s is within 2-σ of the ideal gas value, whereas C_v differs significantly from the ideal gas. However, both are compatible with results expected in a theory with conformal symmetry. We investigate effective measures of conformal symmetry in the high temperature phase of QCD.