  Using a transport model that includes a first-order chiral phase transition
between the partonic and the hadronic matter, we study the development of
density fluctuations in the matter produced in heavy ion collisions as it
undergoes the phase transition, and their time evolution in later hadronic
stage of the collisions. Using the coalescence model to describe the production
of deuterons and tritons from nucleons at the kinetic freeze out, we find that
the yield ratio $ N_\text{t}N_\text{p}/ N_\text{d}^2$, where $N_\text{p}$,
$N_\text{d}$, and $N_\text{t}$ are, respectively, the proton, deuteron, and
triton numbers, is enhanced if the evolution trajectory of the produced matter
in the QCD phase diagram passes through the spinodal region of a first-order
chiral phase transition.
