  A light front field theory for finite temperature and density is currently
being developed. It will be used here to describe the transition region from
quark matter to nuclear matter relevant in heavy ion collisions and in the
early universe. The energy regime addressed is extremely challenging, both
theoretically and experimentally. This is because of the confinement of quarks,
the appearance of bound states and correlations, special relativity, and
nonlinear phenomena that lead to a change of the vacuum structure of quantum
chromodynamics. In the region of the phase transition it eventually leads to a
change of the relevant degrees of freedom. We aim at describing this transition
from quarks to hadronic degrees of freedom in a unified microscopic approach.
