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SUMMARY:Non-Gaussianity in multi-field DBI inflation - Shuntaro Mizuno\, U
 niversity of Nottingham and RESCEU\, University of Tokyo
DTSTART:20091009T120000Z
DTEND:20091009T130000Z
UID:TALK19654@talks.cam.ac.uk
CONTACT:David Seery
DESCRIPTION:Recently\, theoretical models which can produce sizeable non-G
 aussianity has been extensively studied. Among them\, the Dirac-Born-Infel
 d (DBI) inflation model can produce large non-Gaussianity by the fact that
  the sound speed of the perturbations can 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 the inflaton fields are identifie
 d with the positions of a moving D3 brane in the six-dimensional internal 
 space. The dynamics of the D3 brane is described by the DBI action. Howeve
 r\, recently it has been pointed out that single field DBI inflation drive
 n by a mobile D3 brane with large non-Gaussianity might contradict with th
 e current WMAP data.\n\nOne way to avoid these constraints is to consider 
 multi-field DBI\nmodels. Since the position of the brane in each compact d
 irection is described by a scalar field\, DBI inflation is naturally a mul
 ti-field inflationary model. In multi-field inflation models\, the curvatu
 re perturbation is modified on large scales due to the entropy perturbatio
 n.\n\nIn this seminar\, I introduce our recent work on the calculation of 
 the bispectrum and trispectrum in multi-field DBI inflation model.
LOCATION:Pavilion B Potter Room (B1.19)
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