## start date:

Tuesday, January 22, 2019 - 14:00

## Place:

646 A - Mondrian

## Nom:

Christopher Pattison

## Affiliation:

Portsmouth University

## organized by:

I will explain how primordial black holes can form from

perturbations seeded during inflation and how their abundance can be

calculated in the framework of stochastic inflation. This formalism

incorporates quantum backreaction of the small-wavelength fluctuations

on the large distances dynamics of the Universe. If quantum

corrections are small, the probability distribution of density

fluctuations is well approximated by a Gaussian. If they are large,

the PDF has a different profile with a longer tail and leads to

constraints different from the ones usually derived. I will also

discuss the validity of the stochastic formalism beyond the usual

slow-roll approximation, and how, if at all, it must be modified in

such regimes.