  Microscopic transport approaches are the tool to describe the non-equilibrium
evolution in low energy collisions as well as in the late dilute stages of
high-energy collisions. Here, a newly developed hadronic transport approach,
SMASH (Simulating Many Accelerated Strongly-interacting Hadrons) is introduced.
The overall bulk dynamics in low energy heavy ion collisions is shown including
the excitation function of elliptic flow employing several equations of state.
The implications of this new approach for dilepton production are discussed and
preliminary results for afterburner calculations at the highest RHIC energy are
presented and compared to previous UrQMD results. A detailed understanding of a
hadron gas with vacuum properties is required to establish the baseline for the
exploration of the transition to the quark-gluon plasma in heavy ion collisions
at high net baryon densities.

Nuclear Theory;High Energy Physics - Phenomenology;Nuclear Experiment