  The primordial nucleosinthesys of the element can be influenced by the
transitions of phase that take place after the Big Bang, such as the QCD
transition. In order to study the effect of this phase transition, in this work
we compute the time evolution of thermodynamical quantities of the early
universe, focusing on temperature and energy density fluctuations, by solving
the relevant equations of motion using as input the lattice QCD equation of
state to describe the strongly interacting matter in the early universe plasma.
We also study the effect of a primordial strong magnetic field by means of a
phenomenological equation of state. Our results show that small inhomogeneities
of strongly interacting matter in the early Universe are moderately damped
during the crossover.
