  We investigate the dynamics of a first-order quark-hadron transition via
homogeneous thermal nucleation in the two-flavor quark-meson model. The
contribution of the fermionic vacuum loop in the effective thermodynamics
potential and phase diagram together with the location of critical end point
(CEP) have been obtained in the temperature and chemical potential plane. For a
weak and strong first-order phase transition, by taking the temperature as a
variable, the critical bubble profiles, the evolutions of the surface tension
and the saddle-point action in the presence of a nucleation bubble are
numerically calculated in detail when fixing the chemical potentials at
$\mu=306 \mathrm{MeV}$ and $\mu=309 \mathrm{MeV}$. Our results show that the
system could be trapped in the metastable state for a long time as long as the
temperature is between the metastable region characterized by the up and low
spinodal lines. Moreover, the surface tension at criticality will rise up to
about $4 \mathrm{MeV/fm^2}$ when the chemical potential is very high. Such a
small value of the surface tension would favor a mixed phase in the cores of
compact stars and may have an important implication in astrophysics.
