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… 

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References

SHOWING 1-10 OF 31 REFERENCES
Non-Gaussianities in models with a varying inflaton decay rate
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
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
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
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
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
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
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
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
...
1
2
3
4
...