Generic inference of inflation models by non-Gaussianity and primordial power spectrum reconstruction
- Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Str. 1, Garching, D-85748 (Germany)
- Instituto de Ciencias Nucleares, UNAM A. Postal 70-543, Mexico, D.F., 04510 Mexico (Mexico)
- Departamento de Física Fundamental and IUFFyM, Universidad de Salamanca, Plaza de la Merced s/n, Salamanca, 37008 (Spain)
- Arnold Sommerfeld Center for Theoretical Physics, Ludwigs-Maximilians-Universität München, Theresienstraße 37, Munich, D-80333 (Germany)
We present a generic inference method for inflation models from observational data by the usage of higher-order statistics of the curvature perturbation on uniform density hypersurfaces. This method is based on the calculation of the posterior for the primordial non-Gaussianity parameters f{sub NL} and g{sub NL}, which in general depend on specific parameters of inflation and reheating models, and enables to discriminate among the still viable inflation models. To keep analyticity as far as possible to dispense with numerically expensive sampling techniques a saddle-point approximation is introduced, whose precision is validated for a numerical toy example. The mathematical formulation is done in a generic way so that the approach remains applicable to cosmic microwave background data as well as to large scale structure data. Additionally, we review a few currently interesting inflation models and present numerical toy examples thereof in two and three dimensions to demonstrate the efficiency of the higher-order statistics method. A second quantity of interest is the primordial power spectrum. Here, we present two Bayesian methods to infer it from observational data, the so called critical filter and an extension thereof with smoothness prior, both allowing for a non-parametric spectrum reconstruction. These methods are able to reconstruct the spectra of the observed perturbations and the primordial ones of curvature perturbation even in case of non-Gaussianity and partial sky coverage. We argue that observables like T- and B-modes permit to measure both spectra. This also allows to infer the level of non-Gaussianity generated since inflation.
- OSTI ID:
- 22373496
- Journal Information:
- Journal of Cosmology and Astroparticle Physics, Vol. 2014, Issue 06; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 1475-7516
- Country of Publication:
- United States
- Language:
- English
Similar Records
Planck 2015 results: XVII. Constraints on primordial non-Gaussianity
Testing primordial non-gaussianity in cmb anisotropies