Inhomogeneous nucleation in quark hadron phase transition

The effect of subcritical hadron bubbles on a first-order quark-hadron phase transition is studied. These subcritical hadron bubbles created due to thermal fluctuations introduce a finite amount of phase mixing (quark phase mixed with hadron phase) even at and above the critical temperature. For sufficiently strong transitions, as is expected to be the case for the quark-hadron transition, we show that the amount of phase mixing at the critical temperature remains much below the percolation threshold. Thus, as the system cools below the critical temperature, the transition proceeds through the nucleation of critical-size hadron bubbles from a metastable quark-gluon phase (QGP) within an inhomogeneous background populated by an equilibrium distribution of subcritical hadron bubbles. The inhomogeneity of the medium is incorporated consistently by modeling the subcritical bubbles as Gaussian fluctuations, resulting in a large reduction of the nucleation barrier for the critical bubbles. Using the corrected nucleation barrier, we estimate the amount of supercooling for different parameters controlling the phase transition. PACS number(s): 12.38.Mh, 64.60.Qb, 05.70.Fh, 25.75-q, 98.80.Cq