Out of the white hole: a holographic origin for the Big Bang

by Razieh Pourhasan (Science Institute, University of Iceland)

Monday 23 Mar 2015, 14:30 → 16:00 Europe/Rome

Aula Conversi (Dip. di Fisica - Edificio G. Marconi)

While most of the singularities of General Relativity are expected to be safely hidden behind the event horizons by the cosmic censorship conjecture, we happen to live in the causal future of the classical big bang singularity, whose resolution constitutes the active field of early universe cosmology. Could the big bang be also hidden behind a causal horizon, making us immune to the decadent impacts of a naked singularity? We describe a braneworld description of cosmology with both 4d induced and 5d bulk gravity (otherwise known as Dvali- Gabadadze-Porati, or DGP model), which exhibits this feature: The universe emerges as a spherical 3-brane from the gravitational collapse of 5d matter, in the process of formation of a 5d Schwarzschild black hole. That is, in this holographic picture, it is possible to avoid the big bang singularity. We further propose a holographic origin for the big bang: a pressure singularity of the holographic fluid, which happens inside the white hole horizon, and thus need not be real or imply any pathology.