# 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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## December 7 @ 12:00 - 17:00

Amsterdam, December 7th 2018

The last THC meeting of the solar year takes place in Amsterdam. This meeting includes the opportunity to attend Daniel Baumann’s inaugural lecture for his appointment as full professor at University of Amsterdam. Detailed schedule and locations below.

Program

12:00 – 12:30: Arrival with lunch  Location: Roeterseiland complex, lecture room REC E0.22

12:30 – 13:30: Talk by Rafael Porto (DESY & ICTP Sao Paulo)

Title: Gravitational Collider Physics: From the LHC to LISA

Abstract:

It is indisputable that gravitational wave (GW) science will play a transformative role in astrophysics. It is, however, less clear what impact GW measurements will have to shed light on phenomena beyond our current understanding of gravity and particle physics. In principle, the non-perturbative regime in the dynamics of binary systems may carry the imprint of ‘new physics’. However, the need for numerical modeling, together with the small number of cycles involved, may hinder our ability to pinpoint different scenarios if restricted only to the merger phase. In contrast, an accurate analytic reconstruction of the signal during the inspiral offers a unique opportunity to study physics beyond the Standard Model through GW precision data (GWPD). Yet, the associated computational challenges are enormous. While current GW templates for compact binary sources may be sufficient for detection and crude parameter estimation, they are still too coarse for precision physics. We then find ourselves in a situation similar to particle physics in the pre-LHC era: for key processes within empirical reach theoretical uncertainties may dominate. To move forward, and profit the most from GW observations, more accurate waveforms will be needed. The “effective field theory” approach to the binary inspiral problem in general relativity has been instrumental for the construction of the state-of-the-art GW template bank. In this talk I will review how these novel techniques will provide the building blocks that will enable foundational investigations in physics through GWPD: from probes of dynamical spacetime and strongly interacting matter, to the potential to discover exotic compact objects and ultra-light particles in nature. To conclude I will discuss the theoretical challenges ahead, in modeling the binary’s dynamics, to maximize the discovery potential of GW observations in a new era of explorations of the cosmos.

13:30 – 13:45: Coffee Break

13:45 – 14:45: Talk by Liam McAllister (Cornell University)

Title: The Kreuzer-Skarke Axiverse

Abstract:

I will describe a large ensemble of compactifications of type IIB string theory on Calabi-Yau threefold hypersurfaces, obtained by triangulating polytopes from the Kreuzer-Skarke list. We have developed methods to compute effective theories in the previously-inaccessible region with many Kahler moduli that plausibly contains almost all vacua in this class. We find that ultralight axions are ubiquitous when the $\alpha^{\prime}$ expansion is under control. I will explain how these results can be used to advance our understanding of the string landscape and to test ideas about inflation and weak gravity.

15:00 – 16:00: move to lecture hall Location: Aula Oude Lutherse Kerk

Suggested route here

16:00 – 17:00: Inaugural lecture Daniel Baumann(UvA)

Info here

17:00: Drinks

Date:
December 7
Time:
12:00 - 17:00
Event Category:

### Organizer

Jan Pieter van der Schaar
Website:
http://cosmology.amsterdam/