Courtney M. Peterson, Max Tegmark
We develop an approach for testing inflation models with multiple scalar
fields by linking geometric and kinematical features of their inflationary
Lagrangians to observable quantities like the power spectra, bispectrum, and
trispectrum. Our approach also provides geometric intuition for when a
complicated multi-field model can be well-approximated by a model with one,
two, or a handful of fields. To arrive at these results, we focus on the mode
interactions, simplify them using a novel result, and then explore how these
interactions depend on the geometry of the inflationary Lagrangian and on the
kinematics of the associated field trajectory. In the process, we introduce a
multi-field observable \beta_2 that can potentially distinguish two-field
scenarios from scenarios involving three or more effective fields. We also
present a multi-field consistency relation, which involves the primordial
bispectrum parameter f_{NL}, trispectrum parameter \tau_{NL}, and other
spectral observables. These combined results provide better intuition into how
features in multi-field inflationary Lagrangians translate into cosmic
observables.
View original:
http://arxiv.org/abs/1111.0927
No comments:
Post a Comment