Theoretical cosmology meeting

02Dec2016 12:00 - 18:00


Next meeting: Friday 2 Dec, Groningen. Speakers: Timm Wrase (TU Vienna), Gui Pimentel (UvA Amsterdam) and David Stefanyszyn (RUG Groningen)


11:15 Coffee

11:30-12:30 Timm Wrase (TU Vienna)  

dS vacua and inflation in supergravity 

12:30-14:00 Lunch break

14:00-15:00 Gui Pimentel (UvA Amsterdam) 

Symmetries of Cosmological Fluctuations 

15:00-15:30 Coffee Break

15:30-16:30 David Stefanyszyn (RUG Groningen) 

Scalar field scattering amplitudes, soft limits and symmetries

16:30-18:00 Borrel


Timm Wrase (TU Vienna)  

dS vacua and inflation in supergravity 

I will discuss how a new ingredient, the so called nilpotent chiral superfield, has led to tremendous progress in cosmological model building in the context of supergravity.

Gui Pimentel (UvA Amsterdam)

Symmetries of Cosmological Fluctuations 

The assumption that inflationary fluctuations realize de Sitter isometries – an analogue of imposing Lorentz invariance of scattering amplitudes in flat space – imply that various primordial correlation functions are essentially fixed by symmetries. I will present (some recent, others not so recent) results related to the scalar and tensor power spectra and bispectra, which follow from symmetry considerations. If conformal symmetry is explicitly broken, non-Gaussianity is enhanced, at the cost of making them more model-dependent. In a very optimistic scenario, these large non-Gaussianities would permit us to use the early universe as a particle collider, and perform spectroscopy of heavy fields during inflation.

David Stefanyszyn (RUG Groningen)

Scalar field scattering amplitudes, soft limits and symmetries

I will discuss recent developments in classifying and constructing effective field theories of a massless scalar field based on the behaviour of scattering amplitudes in the limit where the momentum of one particle is taken soft. The relationship between non-trivial behaviour of the soft amplitudes and the presence of symmetries will be explained and by studying amplitudes for a very general class of theories, all symmetries beyond a constant shift of the scalar will be identified. 


Room 216 of the University College, Hoendiepskade 23/24, walking distance from Groningen Central Station. 

source: THC@NL

Published by  D-ITP