Fundamentality, universality and the emergence of spacetime: the case of Group Field Theory

The broad goal of quantum gravity projects is the formulation of a theory that combines and integrates general relativity and quantum field theory. Group field theory, a promising candidate for a theory of quantum gravity, depicts the universe as a quantum many-body system resulting from the collective behaviour of an underlying set of discrete, pre-geometric quantum entities called atoms of space(time). These quantum entities cannot be interpreted in terms of either gravitational or geometric properties. Rather, it is the very interaction among them which is supposed to allow for the “emergence” of spacetime in a phase transition termed geometrogenesis. The aim of the present project is to provide an in-depth analysis of the premises, methodologies and theoretical consequences of the group field theory approach. In particular, my objective will be to scrutinize some interpretative facets appearing in this approach to quantum gravity, such as what notion of discreteness can be defined in a non-spatiotemporal environment, what are the features of geometrogenesis, and what is the role played by the so-called relational strategy in the cosmological sector of the theory. Moreover, I will explore the interplay between the notions of fundamentality and universality, as well as the explanatory import of renormalization group methods to account for such interplay. Finally, I will try to understand whether and how the emergence of spacetime in group field theory can be characterized in functional terms and what implications for the ontology of spacetime follow from this theoretical scenario.