Date: Wednesday Nov 19th
Time: 13:30
Title: Backreactions in Quantum Cosmological Perturbation Theory
Abstract:
Cosmological
perturbation theory has a long tradition for describing the early
phases of the Universe. As the observations of the CMB radiation
suggest, it is reasonable, at least as a first approximation, to
implement cosmological inhomogeneities as small perturbations around
homogeneous and isotropic FRW solutions. In these approaches,
backreactions between the inhomogeneities and the background
are usually neglected. There is an ongoing debate about how and to which
extend these backreactions affect the large scale structure of the
Universe. Even at a purely classical level, there is no conclusive
answer to this question yet.
In
my talk, I am going to present a new systematic formalism for
implementing backreactions in cosmological perturbation theory, in which
both,
the perturbations and the homogeneous degrees of freedom are considered
as quantum degrees of freedom. As a more realistic theory of quantum
fields on quantum cosmological space times, it can help to close the gap
between a full theory of quantum gravity and
symmetry-reduced models of quantum cosmology, and to confront these
theories with observations. Our results show that quantum backreactions
imply non-trivial corrections that are potentially phenomenologically
significant.
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