# Upcoming seminars

28/11/2019, 16:00 ** Guillermo Ballesteros (Autonoma University, Madrid)**, Primordial black hole dark matter from inflation

21/11/2019, 16:00 ** Giovanni Acquaviva (Charles University, Prague, CZ)**, Emergent gravity, Bekenstein bound and unitarity

**28/11/2019 -- Guillermo Ballesteros (Autonoma University, Madrid)**

Place: 226

I will discuss the idea that black holes may constitute a large fraction of the Universe’s dark matter, focusing mostly on their formation from large primordial fluctuations generated during inflation. I will summarize the ups and downs of this mechanism and explain some ideas that help to alleviate its main shortcomings.

**21/11/2019 -- Giovanni Acquaviva (Charles University, Prague, CZ)**

Place: 226

It is known that the entropy of a system contained in a certain volume is bounded from above by the entropy of a black hole with corresponding surface area. We relate such universal bound to the existence of fundamental degrees of freedom and provide model-independent considerations about their features. In particular, both geometry and fields propagating on it are seen as phenomena emergent from the more fundamental dynamics, in analogy with many examples in condensed matter physics. An immediate consequence is that, even though the fundamental evolution is considered unitary, the fields develop an entanglement with the spacetime geometry, hence leading to an effective non-unitary evolution on the emergent level. We exemplify some consequences of this scenario by providing a toy-model of black hole evaporation: the entanglement between geometry and fields is interpreted at our low-energy scales as an effective loss of information in Hawking radiation. A question currently under scrutiny is how can unitary and continuum quantum field theory emerge from such fundamental picture.