The Geneva Symmetry Group and Beyond Spacetime present
Daniele Oriti (Albert Einstein Institute, Golm):
If space and time are emergent (in quantum gravity), what is cosmology?
Wednesday, 28 October 2015, 16:15
2, Rue De-Candolle, Room L107 [Map: http://www.openstreetmap.org/]
Anyone who wishes to attend this talk is welcome.
Abstract: “I will discuss three main conceptual aspects of current developments on the nature of space and time in quantum gravity. The first is the need to broaden the context of quantum gravity itself from a theory of quantum General Relativity to a theory of the microstructure of spacetime, founded on non-spatiotemporal building blocks. This changes to some extent the nature of the problem, brings in a new set of conceptual and technical tools (most notably, the renormalisation group and ideas from condensed matter theory), and makes room for a full-blown notion of “emergence” for spacetime itself.
The second are the various levels of such “spacetime emergence” in quantum gravity, so intended. Each carries new technical issues and opportunities, related for example to the possible phase structure of a quantum gravity system and of the related phase transitions. This deepens the scope of the debate on the nature of spacetime, both philosophically and physically.
The third is a new perspective on cosmology from the quantum gravity point of view, and more specifically in an emergent spacetime scenario. It is based on the notion of geometrogenesis (a phase transition between a geometric and a non-geometric phase) as a physical process in the history of the universe, replacing the classical big bang singularity, and on the interpretation of cosmological dynamics as the hydrodynamic description of the fundamental microscopic quantum dynamics of the building blocks pf spacetime. I will focus on the conceptual aspects, which have a more general interest, but illustrate them with examples of current research in the loop quantum gravity and group field theory approaches to quantum gravity.”