Quantum gravity from the atoms of space to cosmology: the universe as a quantum condensate

by Dr Daniele Oriti (AEI , Postdam, Germania)

Friday 24 Jul 2015, 15:00 → 16:00 Europe/Rome

Aula Teorici (Dipartimento di Fisica e Astronomia)

We discuss some recent developments in the group field theory (GFT) approach to quantum gravity, a promising reformulation of loop quantum gravity and spin foam models, and a generalisation of matrix models for 2d quantum gravity. After introducing the basic ideas of the formalism, we discuss the issue of connecting micro- and macro-physics in quantum gravity, and summarise results on the renormalisation of GFT models and their phase transitions. We focus on the idea of continuum space as a GFT condensate and of a “geometrogenesis” transition in the early universe, and present a derivation of effective cosmological dynamics directly from the fundamental quantum gravity dynamics of these models, inspired by these ideas. This leads to the emergence of an hydrodynamic counterpart of quantum cosmology, incorporating several features of the fundamental theory, similar to the emergence of hydrodynamics in Bose-Einstein condensates. The universe arises then as a condensate of quantum gravity “atoms of space”.

Slides QG-Atoms-Cosmology-reduced.pdf