Theoretical Cosmology meetings

To actively encourage the field of theoretical cosmology and to set an informal stage for the exchange of ideas, the Dutch theoretical cosmology community organizes Friday afternoon meetings approximately 6 times a year — usually on the first Friday of the month. The meetings typically start in the afternoon with a main speaker, followed by a short break to continue with another seminar or journal club discussion on some topic of current interest. We end the afternoon with drinks. The supporting institutes in Leiden, Amsterdam, Groningen, Utrecht where recently joined by the strings and cosmology group in Leuven and take turns in hosting the event.

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Leuven Spring 2019

May 10 @ 12:00 - 17:00

Leuven, May 10th. The meeting will take place at Mgr. Sencie Instituut (MSI1), Erasmusplein 2, 3000 Leuven .

Program

13:00 – 14:00: Talk by Matthias Bartelmann (Heidelberg University)

Title: An analytic approach to non-linear cosmic structure formation

Abstract:

 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.

14:00 – 15:00: Talk by Nicola Tamanini(AEI Potsdam)

Title: Cosmology with gravitational wave standard sirens: current results and future prospectives

Abstract:

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.

15:00 – 15:30: Coffee

15:30 – 16:30: Talk by Marjorie Schillo (Uppsala University)

Title: Accelerated expansion from decaying AdS

Abstract:

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.

 

Details

Date:
May 10
Time:
12:00 - 17:00
Event Category:
Website:
https://fys.kuleuven.be/gwc/activities-folder/GWseminars

Organizer

Thomas Van Riet, Thomas Hertog & Bert Vercnocke

Venue

Mgr. Sencie Instituut (MSI1)
Erasmusplein 2
Leuven, 3000 Belgium
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