Non-Gaussianity in multi-field DBI inflation

Add to your list(s) Download to your calendar using vCal

• Shuntaro Mizuno, University of Nottingham and RESCEU, University of Tokyo
• Friday 09 October 2009, 13:00-14:00
• Pavilion B Potter Room (B1.19).

If you have a question about this talk, please contact David Seery.

Recently, theoretical models which can produce sizeable non-Gaussianity has been extensively studied. Among them, the Dirac-Born-Infeld (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.

DBI inflation models are also well motivated by string theory so that the inflaton fields are identified 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. However, recently it has been pointed out that single field DBI inflation driven by a mobile D3 brane with large non-Gaussianity might contradict with the current WMAP data.

One way to avoid these constraints is to consider multi-field DBI models. Since the position of the brane in each compact direction is described by a scalar field, DBI inflation is naturally a multi-field inflationary model. In multi-field inflation models, the curvature perturbation is modified on large scales due to the entropy perturbation.

In this seminar, I introduce our recent work on the calculation of the bispectrum and trispectrum in multi-field DBI inflation model.

This talk is part of the DAMTP Friday GR Seminar series.

This talk is included in these lists:

• All CMS events
• All Talks (aka the CURE list)
• CMS Events
• Cosmology lists
• Cosmology, Astrophysics and General Relativity
• DAMTP Friday GR Seminar
• DAMTP info aggregator
• Interested Talks
• Kavli Institute for Cosmology Talk Lists
• Pavilion B Potter Room (B1.19)
• Priscilla
• School of Physical Sciences
• bld31

Note that ex-directory lists are not shown.