The universe as a condensate of spacetime atoms

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Steffen Gielen (Nottingham)

22 March 2019

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', ie 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.