For best experience please turn on javascript and use a modern browser!

Speakers: Toshifumi Noumi (Kobe University) and Alex Cole (University of Wisconsin-Madison). Location: Amsterdam.

Detail Summary
Date 6 December 2019
Time 13:00 -17:30


14:00 – 15:00 Toshifumi Noumi (Kobe University) - Enlarging the scope of the cosmological collider: Beyond the positivity bounds 

15:00 – 15:30 Coffee Break

15:30 – 16:30 Alex Cole (University of Wisconsin-Madison) Simplices in the Sky - Constraining Cosmology with Computational Topology  

16:30 – 17:30 Borrel


Toshifumi Noumi (Kobe University 

Enlarging the scope of the cosmological collider: Beyond the positivity bounds

Abstract: The energy scale of inflation could be as high as 10^14 GeV, hence it is a phenomenon at the highest energy scale we may explore. Primordial non-Gaussianities can then be thought of as a 10^14 GeV collider (dubbed the cosmological collider), which may be used to probe new particles at the inflationary scale.

In this talk I will discuss how to read of the mass and spin of new particles at various scales from non-Gaussianities. In particular I will demonstrate that signs of inflaton effective interactions (which are not constrained by the positivity bounds) are useful to probe spins of particles heavier than the Hubble scale.

Alex Cole (University of Wisconsin-Madison)

Simplices in the Sky — Constraining Cosmology with Computational Topology  

Abstract: In this talk, I will describe how persistent homology, a somewhat recent development in computational topology and the main pillar of Topological Data Analysis (TDA), is a useful tool for characterizing cosmological observables in the search for new physics. After motivating the utility of developing new perspectives for analyzing cosmological data, I will review the basics of persistent homology. I will then describe how persistent homology connects to several topological statistics that have appeared previously in the cosmology literature, and how it is strictly more powerful than these statistics. To see how much mileage our improved method gives us, I will outline two applications of persistent homology to cosmology: one project with G. Shiu on primordial non-Gaussianity and the CMB (1712.08159), and work in progress with G. Shiu and M. Biagetti regarding LSS.


The meeting will take place in Amsterdam, at Nikhef, Science Park 105 in room H331.

Local organiser

Jan Pieter van der Schaar,


These meetings occur (roughly) every month and are hosted by universities across the Netherlands and sometimes Belgium, gathering the local cosmology community. Some of these talks might be of interest also for string and the Amsterdam GRAPPA groups, so we encourage you to subscribe to the THC mailing list:

and to follow our website to keep up to date on THC meetings dates and programs.