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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Amsterdam Spring 2022
01/04/2022 @ 13:00 - 17:00
Amsterdam, April 1st.
This meeting will take place in an hybrid format. Here the information for connecting:
Time: April 1st, 2022 01:00 PM Amsterdam Time
Join Zoom Meeting
Zoom Link
Meeting ID: 851 1023 6334
Passcode: 845161
13:00-14:00 CET: Talk by Guido d’Amico (University of Parma)
Title: The Cosmological Analysis of the SDSS/BOSS data from the EFTofLSS
Abstract:
The Effective Field Theory of Large-Scale Structure is a perturbative formalism that allows us to predict the clustering of Cosmological Large-Scale Structure in the mildly non-linear regime in an accurate and reliable way.
After a brief illustration of the theory, I will discuss recent results on its application to the analysis of galaxy clustering data.
14:00-15:00 CET: Talk by Manus Visser (Cambridge)
Title: De Sitter Entropy and the Gravitational Path Integral
Abstract:
Gibbons and Hawking famously derived the de Sitter horizon entropy from the Euclidean gravitational path integral in the saddle point approximation. This result is a crucial hint for quantum gravity in de Sitter space, as it suggests that the Hilbert space is finite dimensional. In this talk we extend this result in two different ways. First, we compute the entropy of de Sitter black holes from the on-shell Euclidean action, and take their contributions in the gravitational path integral into account using the formalism of constrained instantons. We use this to calculate the pair creation rate of arbitrary mass black holes in de Sitter space. Second, in two-dimensional de Sitter space we show how the generalized entropy (the sum of the classical gravitational entropy and matter entanglement entropy) can be obtained from an on-shell action for semiclassical dilaton gravity in the microcanonical ensemble. Minimizing the action yields extremizing the generalized entropy, consistent with the island formula.
15:00-15:30 CET: Coffee Break
15:30-16:30 CET: Talk by Moritz Munchmeyer (University of Wisconsin-Madison)
Title: Two machine learning based methods for field-level inference in cosmology
Abstract:
Abstract: In the first part of this talk I will discuss how normalizing flows can be used to learn the probability distribution of non-Gaussian fields in cosmology. I will show novel applications of this recent development from probabilistic machine learning to inference and simulation of the matter distribution of the universe. In the second part of this talk I will present a novel approach for robust inference of local primordial non-Gaussianity. This method combines the sensitivity of neural networks with the analytic control of scale-dependent bias. Both methods are promising tools to help analyzing future high-resolution survey data in the non-linear regime.
16:30 CET: Drinks