Steffen Gielen (Nottingham)
Title: The universe as a condensate of spacetime atoms
Abstract: In the standard picture of cosmology, the Universe began at
the Big Bang; the Big Bang itself is a singularity where the laws of
physics break down. A quantum theory of gravity should resolve this
singularity and help in understanding the initial state of the Universe
needed to account for present observations. I will present some progress
towards this goal in the group field theory approach to quantum gravity,
using the idea of a universe formed as a "condensate", i.e. a very
homogeneous quantum configuration, from a large number of discrete
building blocks of geometry. I will show how this setting produces new
cosmological models without an initial singularity; demanding that such
models be both theoretically self-consistent and potentially compatible
with observation then gives new ways for constraining theories of
quantum gravity.