| Автор | Antonio De Felice |
| Автор | Shinji Tsujikawa |
| Дата выпуска | 2011-04-01 |
| dc.description | We compute the three-point correlation function of primordial scalar density perturbations in a general single-field inflationary scenario, where a scalar field φ has a direct coupling with the Ricci scalar R and the Gauss-Bonnet term G. Our analysis also covers the models in which the Lagrangian includes a function non-linear in the field kinetic energy X = −(φ)<sup>2</sup>/2, and a Galileon-type field self-interaction G(φ,X)□φ, where G is a function of φ and X. We provide a general analytic formula for the equilateral non-Gaussianity parameter f<sub>NL</sub><sup>equil</sup> associated with the bispectrum of curvature perturbations. A quasi de Sitter approximation in terms of slow-variation parameters allows us to derive a simplified form of f<sub>NL</sub><sup>equil</sup> convenient to constrain various inflation models observationally. If the propagation speed of the scalar perturbations is much smaller than the speed of light, the Gauss-Bonnet term as well as the Galileon-type field self-interaction can give rise to large non-Gaussianities testable in future observations. We also show that, in Brans-Dicke theory with a field potential (including f(R) gravity), f<sub>NL</sub><sup>equil</sup> is of the order of slow-roll parameters as in standard inflation driven by a minimally coupled scalar field. |
| Формат | application.pdf |
| Издатель | Institute of Physics Publishing |
| Название | Primordial non-gaussianities in general modified gravitational models of inflation |
| Тип | paper |
| DOI | 10.1088/1475-7516/2011/04/029 |
| Electronic ISSN | 1475-7516 |
| Журнал | Journal of Cosmology and Astroparticle Physics |
| Том | 2011 |
| Первая страница | 29 |
| Последняя страница | 029 |
| Аффилиация | Antonio De Felice; Department of Physics, Faculty of Science, Tokyo University of Science, 1-3, Kagurazaka, Shinjuku-ku, Tokyo 162-8601, Japan |
| Аффилиация | Shinji Tsujikawa; Department of Physics, Faculty of Science, Tokyo University of Science, 1-3, Kagurazaka, Shinjuku-ku, Tokyo 162-8601, Japan |
| Выпуск | 04 |
