Hydrodynamic bubbles in a transport approach

Hybrid approaches are very successfully applied for the description of the dynamics of heavy ion collisions. In the high density regime one takes advantage of relativistic hydrodynamics, while at lower density non-equilibrium transport models are applied. Handling the transitions between fluid dynamics and the transport description includes uncertainties, both when generating the initial condition by turning particles into fluid and in the final stages, when particles are sampled from the fluid. We suggest a way to avoid these uncertainties by generating hydrodynamical behaviour directly in the transport approach. In the regions of high density we perform a forced thermalization, which effectively simulates the result of N-particle collisions. The effect of these hydrodynamic bubbles on bulk observables such as elliptic flow is investigated by comparing the results to pure transport and traditional hybrid approach.