  We consider an instationary macroscopic system of self-interacting particles
with an additional potential, the so called Bohm's potential. We study the
existence of non-negative global solutions to the (4-th order) system of
equations and allude the differences to results obtained for classical models.
The problem is considered on a bounded domain up to three space dimension,
subject to initial and Neumann boundary condition for the particle density, and
Dirichlet boundary condition for the self-interacting potential. Moreover, the
initial datum is only assumed to be non-negative and to satisfy a weak
integrability condition.
