The shape of non-Gaussianities
@article{Babich2004TheSO, title={The shape of non-Gaussianities}, author={Daniel Babich and Paolo Creminelli and Matias Zaldarriaga}, journal={Journal of Cosmology and Astroparticle Physics}, year={2004}, volume={2004}, pages={009-009} }
We study the dependence on the configuration in momentum space of the primordial three-point function of density perturbations in several different scenarios: standard slow-roll inflation, curvaton and variable decay models, ghost inflation, models with higher derivative operators and the DBI model of inflation. We define a cosine between the distributions using a measure based on the ability of experiments to distinguish between them. We find that models fall into two broad categories with…
430 Citations
Large non-Gaussianities in single-field inflation
- Computer Science
- 2007
While adding features to a potential can improve the fit to the two-point function, these are generically associated with a greatly enhanced signal at the three-point level, which may lead to a consistency check on models of inflation with non-smooth potentials.
Non-Gaussianities in Multi-field Inflation
- Physics
- 2007
We compute the amplitude of the non-Gaussianities in inflationary models with multiple, uncoupled scalar fields. This calculation thus applies to all models of assisted inflation, including…
Primordial Non-Gaussianities from the Trispectra in Multiple Field Inflationary Models
- Mathematics
- 2009
We investigate the primordial non-Gaussianities from the trispectra in multi-field inflation models, which can be seen as generalization of multi-field k-inflation and multi-DBI inflation. We derive…
Non-Gaussianities in two-field inflation
- Physics
- 2006
We study the bispectrum of the curvature perturbation on uniform energy density hypersurfaces in models of inflation with two scalar fields evolving simultaneously. In the case of a separable…
Prospects for constraining the shape of non-Gaussianity with the scale-dependent bias
- Physics
- 2012
We consider whether the non-Gaussian scale-dependent halo bias can be used not only to constrain the local form of non-Gaussianity but also to distinguish among different shapes. In particular, we…
A naturally large four-point function in single field inflation
- Computer Science
- 2011
Using the recently developed Effective Field Theory of Inflation, it is shown that it is possible to impose an approximate parity symmetry and an approximate continuos shift symmetry on the inflaton fluctuations that allow a unique quartic operator, while approximately forbidding all the cubic ones.
Limits on non-Gaussianities from WMAP data
- Mathematics
- 2006
We develop a method for constraining the level of non-Gaussianity of density perturbations when the three-point function is of the 'equilateral' type. Departures from Gaussianity of this form are…
Primordial fluctuations and non-Gaussianities in sidetracked inflation
- PhysicsJournal of Cosmology and Astroparticle Physics
- 2018
Heavy scalar fields can undergo an instability during inflation as a result of their kinetic couplings with the inflaton. This is known as the geometrical destabilization of inflation, as it relies…
Consistency relation and non-Gaussianity in a Galileon inflation
- Physics
- 2016
We study a particular Galileon inflation in the light of Planck2015 observational data in order to constraint the model parameter space. We study the spectrum of the primordial modes of the density…
Testing an Inflation Model with Nonminimal Derivative Coupling in the Light of PLANCK 2015 Data
- Physics
- 2015
We study the dynamics of a generalized inflationary model in which both the scalar field and its derivatives are coupled with the gravity. We consider a general form of the nonminimal derivative…
References
SHOWING 1-10 OF 31 REFERENCES
Non-Gaussianities in models with a varying inflaton decay rate
- Mathematics
- 2004
We consider the expected level of primordial non-Gaussianities in models in which density perturbations are produced by spatial fluctuations in the decay rate of the inflaton. We consider both the…
Non-Gaussianity in multifield inflation
- Physics
- 2002
This article investigates the generation of non-Gaussianity during inflation. In the context of multifield inflation, we detail a mechanism that can create significant primordial non-Gaussianities in…
Cosmological perturbations: Entering the nonlinear regime
- Physics
- 1996
We consider next-to-leading-order (one-loop) nonlinear corrections to the bispectrum and skewness of cosmological density fluctuations induced by gravitational evolution, focusing on the case of…
On non-Gaussianities in single-field inflation
- Physics
- 2003
We study the impact of higher dimension operators in the inflaton Lagrangian on the non-Gaussianity of the scalar spectrum. These terms can strongly enhance the effect without spoiling slow-roll,…
Ghost Inflation
- Physics
- 2003
We propose a new scenario for early cosmology, where an inflationary de Sitter phase is obtained with a ghost condensate. The transition to radiation dominance is triggered by the ghost itself,…
Non-Gaussian features of primordial fluctuations in single field inflationary models
- Mathematics
- 2003
We compute the three point correlation functions for primordial scalar and tensor fluctuations in single field inflationary models. We obtain explicit expressions in the slow roll limit where the…
New mechanism for generating density perturbations from inflation
- Economics
- 2004
We propose a new mechanism to generate density perturbations in inflationary models. Spatial fluctuations in the decay rate of the inflaton field to ordinary matter lead to fluctuations in the…
On the Amount of Gravitational Waves from Inflation
- Physics
- 2004
The curvaton and the inhomogeneous reheating scenarios for the generation of the cosmological curvature perturbation on large scales represent an alternative to the standard slow-roll scenario where…