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CATEGORIES:DAMTP Friday GR Seminar
SUMMARY:Non-Gaussianity in multi-field DBI inflation - Shu
ntaro Mizuno\, University of Nottingham and RESCEU
\, University of Tokyo
DTSTART;TZID=Europe/London:20091009T130000
DTEND;TZID=Europe/London:20091009T140000
UID:TALK19654AThttp://talks.cam.ac.uk
URL:http://talks.cam.ac.uk/talk/index/19654
DESCRIPTION:Recently\, theoretical models which can produce si
zeable non-Gaussianity has been extensively studie
d. Among them\, the Dirac-Born-Infeld (DBI) inflat
ion model can produce large non-Gaussianity by the
fact that the sound speed of the perturbations ca
n be much smaller than one due to the non-trivial
form of the kinetic term.\n\nDBI inflation models
are also well motivated by string theory so that t
he inflaton fields are identified with the positio
ns of a moving D3 brane in the six-dimensional int
ernal space. The dynamics of the D3 brane is descr
ibed by the DBI action. However\, recently it has
been pointed out that single field DBI inflation d
riven by a mobile D3 brane with large non-Gaussian
ity might contradict with the current WMAP data.\n
\nOne way to avoid these constraints is to conside
r multi-field DBI\nmodels. Since the position of t
he brane in each compact direction is described by
a scalar field\, DBI inflation is naturally a mul
ti-field inflationary model. In multi-field inflat
ion models\, the curvature perturbation is modifie
d on large scales due to the entropy perturbation.
\n\nIn this seminar\, I introduce our recent work
on the calculation of the bispectrum and trispectr
um in multi-field DBI inflation model.
LOCATION:Pavilion B Potter Room (B1.19)
CONTACT:David Seery
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