Speaker
Steffen Gielen
Description
Bridging the gap from the Planck scale to cosmological
scales is the ultimate challenge for quantum gravity, but
doing so would allow us to connect the microscopic physics
of quantum gravity to observation through cosmology. In the
group field theory (GFT) approach, a promising working
hypothesis has been that a macroscopic universe emerges from
a "condensate" of many interacting (Planck-scale) degrees of
freedom of quantum geometry. I will give an introduction
into the GFT formalism and discuss the approximations that
have been employed, in analogy to normal Bose-Einstein
condensates, in order to obtain simple, analytically
solvable equations for the emergent cosmology. Most of these
approximations are crude, and numerical techniques may
indeed be necessary for justifying them, thus providing more
solid foundations for the connection of GFT to the universe.
I will also discuss how GFT might one day pass the main test
for any theory of the early universe: explaining the pattern
of the cosmic microwave background.
