Theoretical Cosmology meeting
Speakers: Matthias Bartelmann (Heidelberg University), Nicola Tamanini (AEI Potsdam) and Marjorie Schillo (Uppsala University). Location: Leuven, Belgium.
13:00 – 14:00 Matthias Bartelmann (Heidelberg University) - An analytic approach to non-linear cosmic structure formation
14:00 – 15:00 Nicola Tamanini(AEI Potsdam) - Cosmology with gravitational wave standard sirens: current results and future prospectives
15:30 – 16:30 Marjorie Schillo (Uppsala University) - Accelerated expansion from decaying AdS
Matthias Bartelmann (Heidelberg University)
An analytic approach to non-linear cosmic structure formation
Numerical simulations of cosmic structure formation are impressively successful. However, they have practical and conceptual disadvantages: they are computationally expensive and thus not very flexible; and they reproduce, but do not explain, the universal properties of cosmic structures. I will present a new analytic approach to cosmic structures, which is based on a non- equilibrium statistical field theory for Hamiltonian particle systems. Its main advantage is that it avoids the notorious shell-crossing problem by construction and thus allows to enter deeply into the non-linear regime. I will sketch the concepts of the theory and show the results of several applications, e.g. to the cosmological standard model, axionic dark matter, and modified theories of gravity.
Nicola Tamanini(AEI Potsdam)
Cosmology with gravitational wave standard sirens: current results and future prospectives
I will introduce the concept of standard siren, reviewing the methodologies that one can apply to probe the cosmic expansion using gravitational wave observations. I will then outline the gravitational wave sources that can be used as standard sirens for both Earth-based (LIGO/Virgo) and space-based (LISA) detectors, pointing out for which of them an electromagnetic counterpart is expected to be observed. I will then discuss the constraints on the Hubble constant recently obtained from GW170817, which represents the very first standard siren ever discovered, and discuss future cosmological prospects for LIGO/Virgo. Finally I will present cosmological forecasts for LISA, which will be able to probe the expansion of the universe at high redshift.
Marjorie Schillo (Uppsala University)
Accelerated expansion from decaying AdS
I will discuss a recent construction wherein an effective de Sitter spacetime appears as a non-supersymmetric AdS vacuum decays into the supersymmetric vacuum. Four-dimensional observers are localized on a spherical brane which nucleates to facilitate the decay. The expansion of the brane bubble then leads to an effective four-dimensional de Sitter space. This construction side-steps the difficulties of constructing scale-separated de Sitter vacua or inflating spacetimes in traditional flux compactifications. I will discuss new developments concerning four-dimensional phenomenology and the embedding of the scenario in string theory.
Thomas Van Riet
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