**Fabio Mele and Johannes Muench, University of Regensburg**

**Title: Effective Quantum Extended Spacetime of Polymer Schwarzschild Black Hole**

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By Jorge Pullin, LSU

When one crosses the horizon into a black hole the role of time and radius get interchanged. One is inevitably dragged into "the future" along the r direction towards the singularity at r=-0. The metric of the space-time, which outside the black hole depends on r, inside depends on t, it becomes time dependent as if it were a cosmological space-time. This in fact can be made into a mathematically precise correspondence. The space-time in the interior of a black hole is equivalent to a type of cosmology known as Kantowksi-Sachs. This led people to study it using loop quantum cosmology tools. In particular one finds that the singularity inside black holes gets replaced by a "bounce" into another region in space-time just like the Big Bang is replaced by a bounce in loop quantum cosmology.

This talk focused on some technical issues of these types of studies. In particular, when one studies physically observable quantities, mathematically one finds there are two of them, but only one has a physical interpretation, it is the mass of the black hole. Through a change of variables the authors were able to identify physically two observable quantities. They correspond to the mass of the black hole and the mass of the "white hole" that emerges once one bounces through the singularity. The new variables have several other advantages, in particular they simplify the dynamics quite a bit and it actually becomes exactly solvable.