Quantitative bispectra from multifield inflation Rigopoulos, G. I.; Shellard, E. P. S.; van Tent, B. J. W.
Physical review. D, Particles, fields, gravitation, and cosmology,
10/2007, Letnik:
76, Številka:
8
Journal Article
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After simplifying and improving the non-Gaussian formalism we developed in previous work, we derive a quantitative expression for the three-point correlator (bispectrum) of the curvature perturbation ...in general multiple-field inflation models. Our result describes the evolution of non-Gaussianity on superhorizon scales caused by the nonlinear influence of isocurvature perturbations on the adiabatic perturbation during inflation. We then study a simple quadratic two-field potential and find that when slow roll breaks down and the field trajectory changes direction in field space, the non-Gaussianity can become large. However, for the simple models studied to date, the magnitude of this non-Gaussianity decays away after the isocurvature mode is converted into the adiabatic mode.
Simple route to non-Gaussianity in inflation Rigopoulos, G. I.; Shellard, E. P. S.; van Tent, B. J. W.
Physical review. D, Particles, fields, gravitation, and cosmology,
10/2005, Letnik:
72, Številka:
8
Journal Article
We present a new flexible estimator for comparing theoretical templates for the predicted bispectrum of the cosmic microwave background (CMB) anisotropy to observations. This estimator, based on ...binning in harmonic space, generalizes the ‘optimal’ estimator of Komatsu, Spergel and Wandelt by allowing an adjustable weighting scheme for masking possible foreground and other contaminants and detecting particular noteworthy features in the bispectrum. The utility of this estimator is illustrated by demonstrating how acoustic oscillations in the bispectrum and other details of the bispectral shape could be detected in the future Planck data provided that fNL is sufficiently large. The character and statistical weight of the acoustic oscillations and the decay tail are described in detail.
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