University of Nottingham

## Talks by Thomas Sotiriou

## Parallel Discussion Session: Observations at the interface of strong gravity and QG

Thomas Sotiriou
University of Nottingham

## Black holes without Lorentz symmetry

Thomas Sotiriou
University of Nottingham

Our current definition of what a black hole is relies heavily on the assumption that there exists a finite maximum speed of propagation for any signal. Indeed, one is tempted to think that the notion of a black hole has no place in a world with infinitely fast signal propagation. I will use concrete examples from Lorentz-violating gravity theories to demonstrate that this naive expectation is not necessarily true.

## Coming of Age for Horava Gravity: from Renormalizability to Black Holes

Thomas Sotiriou
University of Nottingham

After giving
an overview of the basic features of Horava gravity, I will focus on the latest developments and argue that, at least for the most general and complete version of the theory, the infrared phenomenology is by now relatively well understood and pathologies have been tamed. This implies that time has come for the theory to face a new series of intriguing challenges, related to quantization, ultraviolet phenomenology, black holes and singularities etc. I will present some ideas and first results in some of these directions.