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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Leiden Spring 2018

April 6 @ 14:00 - 17:00

Leiden, April 6th, 2018

The meeting will take place in Leiden, room 408 in the Snellius Building (Niels Bohrweg 1).

14:00 – 15:00 Talk by José Juán Blanco Pillado (UPV-EHU Bilbao),

Title: Gravitational Waves from Cosmic Strings

Abstract:

I will give a brief introduction to the theory of cosmic strings
in the early universe and discuss recent progress
in our understanding of the evolution of a string network.
I will then discuss the production of gravitational waves
from this network and how this leads to prediction of a
stochastic background of gravitational waves covering
a wide range of frequencies. Finally, I will also discuss the
implications of these predictions for the gravitational
wave observations at the PTA range as well as the LIGO
and LISA observatories.15:00-15:30 Coffee15:30-16:30 Talk by Krzysztof Turzynski (Warsaw University)

Title: Geometrical destabilization and reheating

Abstract:

In multi-field inflationary models, the curvature of the field space manifold can dominate the stabilizing force from the potential and destabilize inflationary trajectories: a phenomenon called geometrical destablization. An interesting example of this effect can be found in alpha-attractor T-models of inflation with small alpha <~10^(-3). The “spectator” field, which is heavy during inflation and does not participate in inflationary dynamics, becomes tachyonic as the inflaton gains speed and the perturbations of that dominate the dynamics of the early stages of reheating. As a result, the transition from the inflationary era to radiation domination era is practically instantaneous and much faster than previously found in an effective theory including only the inflaton field.

16:30 – Borrel

Details

Date:
April 6
Time:
14:00 - 17:00
Event Category:

Organizer

Ana Achucarro
Website:
https://www.lorentz.leidenuniv.nl/cosmology/

Venue

Institute Lorentz Leiden
Niels Bohrweg 2
Leiden, 2333 CA Netherlands
+ Google Map
Phone:
+31715275505
Website:
www.lorentz.leidenuniv.nl