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CATEGORIES:Cosmology Lunch
SUMMARY:Simple emergent power spectra from complex inflati
onary physics - Mafalda Dias (DESY)
DTSTART;TZID=Europe/London:20160606T130000
DTEND;TZID=Europe/London:20160606T140000
UID:TALK66310AThttp://talks.cam.ac.uk
URL:http://talks.cam.ac.uk/talk/index/66310
DESCRIPTION:An ultraviolet-complete description of inflation m
ay not be simple. Indeed\, the large number of sca
lar fields appearing in the low energy effective d
escription of string compactifications motivates t
he idea of inflation occurring on a complicated hi
gh-dimensional\, essentially random\, potential. I
t is far from clear that such scenarios are compat
ible with the simple observed primordial power spe
ctrum\, fully described by its amplitude and tilt.
One might expect that the complicated dynamics oc
curring in such a potential would result in a high
ly non-linear spectrum. To address this question\,
two computational problems must be overcome\, one
at the level of the background and one regarding
perturbations. In this talk I will describe how n
on-equilibrium random matrix theory can be used to
solve both of these problems. As we will see\, wh
en the number of fields is small\, the heavily fea
tured potentials give rise to power spectra that a
re indeed highly non-linear. However\, when the nu
mber of fields is large\, the spectrum simplifies
considerably and we find inflationary realisations
with an approximately linear power spectrum. Henc
e\, we provide proof of principle that complicated
inflationary models as motivated by some string t
heory scenarios can be compatible with observation
. I will also discuss how these simple power spect
ra can be interpreted as an emergent property of l
arge N dynamics which can be understood in terms o
f the well known phenomenon of eigenvalue repulsio
n in random matrix theory.
LOCATION:CMS\, Pav. B\, CTC Common Room (B1.19) [Potter Roo
m]
CONTACT:Tommaso Giannantonio
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