ar X iv : g r - qc / 9 60 70 40 v 1 1 8 Ju l 1 99 6 Creation of multiple de Sitter universes inside

A classical model for the interior structure of a Schwarzschild black hole which consists in creating multiple de Sitter universes with lightlike boundaries is proposed.The interaction of the boundaries is studied and a scenario leading to disconnected de Sitter universes is described. The interior structure of a black hole and its final state after evaporation are still two intriguing problems.Their study requires the knowledge of physics at Planckian scales and it is generally believed that only a junction of quantum theory to gravity will provide a proper solution.Quantum effects become important as one penetrates deeply inside the horizon of a black hole and it is hoped that they will prevent the formation of a singularity which,in classical general relativity, is the unavoidable end state of gravitational collapse according to Penrose's theorem (let us recall that a singular behavior already happens at the Cauchy horizon of a charged or rotating black hole). Following these ideas a classical singularity-free model for the internal evolution of a Schwarzchild black hole was proposed by Frolov, Markov and Mukhanov (FMM) [1] a few years ago.It relies upon two assumptions-i)limiting curvature hypothesis [2]-ii)transition to a de Sitter state in the final stage of gravitational collapse. Justifications of these two assumptions can be found in the existence of corrective terms in the effective action for gravity, i.e. Polchinsky [3],Mukhanov and Brandenberger [4]. It has also been shown [5] that the vacuum polarization inside the horizon of a Schwarzschild black hole can have a 1