Mild quasilocal non-Gaussianity as a signature of modified gravity during inflation

Nicola Bartolo; Dario Cannone; Raul Jimenez; Sabino Matarrese; Licia Verde

doi:10.1103/PhysRevLett.113.161303

Mild quasilocal non-Gaussianity as a signature of modified gravity during inflation

Phys Rev Lett. 2014 Oct 17;113(16):161303. doi: 10.1103/PhysRevLett.113.161303. Epub 2014 Oct 17.

Authors

Nicola Bartolo¹, Dario Cannone¹, Raul Jimenez², Sabino Matarrese³, Licia Verde⁴

Affiliations

¹ Dipartimento di Fisica e Astronomia G. Galilei, Università degli Studi di Padova, I-35131 Padova, Italy and INFN, Sezione di Padova, I-35131 Padova, Italy.
² ICREA & ICC, University of Barcelona, Marti i Franques 1, Barcelona 08028, Spain and Institute for Applied Computational Science, Harvard University, Massachusetts 02138, USA.
³ Dipartimento di Fisica e Astronomia G. Galilei, Università degli Studi di Padova, I-35131 Padova, Italy and INFN, Sezione di Padova, I-35131 Padova, Italy and Gran Sasso Science Institute (INFN), viale F. Crispi 7, 67100 L'Aquila, Italy.
⁴ ICREA & ICC, University of Barcelona, Marti i Franques 1, Barcelona 08028, Spain and Institute of Theoretical Astrophysics, University of Oslo, 0315 Oslo, Norway.

PMID: 25361248
DOI: 10.1103/PhysRevLett.113.161303

Abstract

We show that modifications of Einstein gravity during inflation could leave potentially measurable imprints on cosmological observables in the form of non-Gaussian perturbations. This is due to the fact that these modifications appear in the form of an extra field that could have nontrivial interactions with the inflaton. We show it explicitly for the case R+αR(2), where nearly scale-invariant non-Gaussianity at the level of f(NL) ≈ - (1 to 30) can be obtained, in a quasilocal configuration.