Generation of fluctuations from the quark-hadron transition in the early universe

We present a model for the generation of isothermal baryon density fluctuations in the early universe associated with the quark-hadron transition. The model is based on thermal nucleation theory for the creation of bubbles of the new phase and on entropy conservation during the phase transition. We find that the baryon number transport characteristics together with the rapid motion of the phase boundary can result in baryon density fluctuations with amplitudes considerably larger than the chemical equilibrium limit. All of these results depend on uncertain quantities associated with the underlying QCD physics. We discuss how uncertainties in these quantities translate into uncertainties in the fluctuation amplitude, shape, and mean separation