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The inflationary bispectrum with curved field-space
journal contribution
posted on 2023-06-08, 13:39 authored by Joseph Elliston, David SeeryDavid Seery, Reza TavakolWe compute the covariant three-point function near horizon-crossing for a system of slowly-rolling scalar fields during an inflationary epoch, allowing for an arbitrary field-space metric. We show explicitly how to compute its subsequent evolution using a covariantized version of the separate universe or "delta-N" expansion, which must be augmented by terms measuring curvature of the field-space manifold, and give the nonlinear gauge transformation to the comoving curvature perturbation. Nonlinearities induced by the field-space curvature terms are a new and potentially significant source of non-Gaussianity. We show how inflationary models with non-minimal coupling to the spacetime Ricci scalar can be accommodated within this framework. This yields a simple toolkit allowing the bispectrum to be computed in models with non-negligible field-space curvature.
History
Publication status
- Published
File Version
- Accepted version
Journal
Journal of Cosmology and Astroparticle PhysicsISSN
1475-7516Publisher
Institute of PhysicsExternal DOI
Issue
11Volume
2012Department affiliated with
- Physics and Astronomy Publications
Full text available
- Yes
Peer reviewed?
- Yes
Legacy Posted Date
2014-09-08First Open Access (FOA) Date
2016-03-22First Compliant Deposit (FCD) Date
2014-09-07Usage metrics
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