Black holes with rotating quantum dust cores

Classical gravitational collapse models suggest the existence of spacetime singularities, where one expects Einstein's general relativity to break down. There are several approaches in the literature to avoid such singularities, by either imposing regularity conditions inspired by classical physics or attempting to give quantum mechanical description to the existing collapse models. Here, we review a recent proposal in which the collapse is modelled as a dust ball with a sequence of layers. By quantising the trajectories of dust particles in each layer, one finds a collective ground state for the core which has a radius of 3G_NM/2, thus supporting the idea that black holes can be macroscopic extended objects. We then discuss the effects of rotation on the core by following the analysis in, which shows that increasing (classical) angular momentum increases the core radius but corresponds to a smaller outer horizon while removing the inner horizon completely within the perturbative approximation. Finally, we repeat a similar analysis for a more ``realistic" case in which we consider the geometry to be described by the Kerr metric and observe that it yields similar results.