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Speakers: Austin Joyce (Delta ITP/UvA), William Coulton (Kavli Cambridge) and Azadeh Moradinezhad (Geneva University). Location: Groningen.

Event details of Theoretical Cosmology meeting
Date 6 March 2020
Time 12:15 -18:00


12:15 – 13:15 Austin Joyce (UvA) - Cosmological Correlation Functions From Symmetries and Factorization 

13:15 – 14:15 Lunch Break 

14:15 – 15:15 William Coulton (Kavli Cambridge) - The prospects and challenges of primordial non-Gaussianity searches with future CMB experiments

15:15 – 15:45 Coffee Break 

15:45 – 16:45 Azadeh Moradinezhad(Geneva University) - Probing primordial non-Gaussianity (PNG) with the large-scale structure (LSS) across cosmic times 

16:45 Borrel


Austin Joyce (UvA) 

Cosmological Correlation Functions From Symmetries and Factorization

Abstract: The large-scale correlations that we observe in the distribution of matter in the Universe have their origins in primordial perturbations produced prior to the hot big bang—likely during a period of inflationary expansion. The correlations in these primordial perturbations carry information about the dynamics of the inflationary period, but the details of how this dynamical information is encoded are not fully understood. I will discuss recent progress toward such a systematic understanding of cosmological correlation functions. In particular, the structure of cosmological correlators is highly constrained by symmetry and by other fundamental considerations, like locality. In some cases these constraints are sufficiently strong as to fix the answer completely. I will review these symmetry and locality constraints in the quasi-de Sitter inflationary spacetime and describe how they constrain correlation functions, focusing on the case where the fields involved have spin. 

William Coulton (Kavli Cambridge) 

The prospects and challenges of primordial non-Gaussianity searches with future CMB experiments 

Abstract: Signatures of primordial non-Gaussianity (PNG) are one of the most powerful means of probing the physics of the early universe. The linear nature of the CMB makes it ideal for searching for PNG, with the current best constraints on PNG coming from the \textit{Planck} Satellite. The Simons Observatory is an upcoming ground based CMB experiment based in the Atacama, Chile. I will discuss how the Simons Observatory will improve our knowledge of primordial non-Gaussianity. To achieve these improvements we have to push to smaller scales and I will describe some of the challenges this produces, as well as paths to overcome them. Finally I will discuss how measurements of Ralyeigh scattering, in the further future, could be used to aid searches of PNG. 

Azadeh Moradinezhad(Geneva University) 

Probing primordial non-Gaussianity (PNG) with the large-scale structure (LSS) across cosmic times 

Abstract: The non-Gaussianity of the initial conditions leaves its imprints on statistical properties of the dark matter and its biased tracers. The upcoming wide-field optical galaxy surveys are expected to significantly improve the current constraints on PNG from measurements of the anisotropies of the cosmic microwave background. Furthermore, measurements of the integrated emission of spectral lines from galaxies and the intergalactic medium via a technique referred to as line intensity mapping, provide a mean to probe the LSS at redshifts and scales not accessible to traditional galaxy surveys. In this talk, I will discuss some of our recent works on the prospects of constraining PNG with these two tracers. In the first part of the talk, focusing on the 3-point statistics of the galaxy distribution, first I will describe the possibility of constraining the presence of inflationary-era new particles with the galaxy bispectrum. Second, I will discuss the idea of constructing estimators that capture the information of the bispectrum on PNG but are potentially simpler and hence more optimal than the standard bispectrum. In the second part, focusing on 2-point statistics, I will discuss the prospects of intensity mapping with rotational lines of carbon monoxide CO, and the fine structure line of ionised carbon [CII], as well as their synergies with galaxy surveys to constrain PNG.


The meeting will take place in room 5159.0291 at the Energy Academy on Zernike Campus, Nijenborgh 6, 9747 AG Groningen.



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