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CATEGORIES:Cosmology Lunch
SUMMARY:Primordial black holes and stochastic inflation be
yond slow roll - Swagat Saurav Mishra (Nottingham)
DTSTART;TZID=Europe/London:20231009T130000
DTEND;TZID=Europe/London:20231009T140000
UID:TALK205135AThttp://talks.cam.ac.uk
URL:http://talks.cam.ac.uk/talk/index/205135
DESCRIPTION:Primordial Black Holes (PBHs) may form in the earl
y universe\, from the gravitational collapse of la
rge density perturbations\, generated by large qua
ntum fluctuations during inflation. Since PBHs for
m from rare over-densities\, their abundance is se
nsitive to the tail of the primordial probability
distribution function (PDF) of the perturbations.
It is therefore important to calculate the full PD
F of the perturbations\, which can be carried out
non-perturbatively using the 'stochastic inflation
' framework. In single field inflationary models\,
generating large enough perturbations to produce
an interesting abundance of PBHs requires violatio
n of slow roll. It is therefore necessary to exten
d the stochastic inflation formalism beyond slow r
oll\, and consequently there has been a surge in t
he research interest in this direction in the rece
nt years. A crucial ingredient for this is the sto
chastic noise matrix corresponding to the small wa
velength fluctuations. In this talk\, after provid
ing a pedagogical introduction to PBHs and ultra
slow-roll inflation\, the speaker will discuss ana
lytical and numerical calculations of these matrix
elements for an inflaton potential with a feature
which violates slow roll and produces large\, pot
entially PBH generating\, perturbations. The semin
ar will be based on the following work carried out
at the Particle Cosmology Group\, University of N
ottingham\, in collaboration with Prof. Edmund J.
Copeland and Prof. Anne M. Green :\nhttps://arxiv.
org/abs/2303.17375
LOCATION:CMS\, Pav. B\, CTC Common Room (B1.19) [Potter Roo
m]
CONTACT:Dr Dong-Gang Wang
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