  Matter in its present form was formed when our
  Universe emerged from the quark-gluon phase (QGP) at about 30mus into its
evolution. To explore this early period in the laboratory, we study highly
excited matter formed in relativistic heavy ion collision experiments: heavy
nuclei crash into each other, and form compressed and energetically excited
nuclear matter, resembling in its key features the stuff which filled the early
Universe. In these experiments we further explore the physics of the vacuum
structure of strongly interacting gauge theory, Quantum Chromodynamics (QCD).
The common beginning for both, heavy ion collisions, and vacuum structure
investigations, is the physics of the quantum electrodynamic (QED) vacuum in
the presence of the supercritical external field that is formed when two highly
charged heavy ions are brought together near to the Coulomb barrier in a
considerably lower reaction energy collision.
