Dynamically generated inflation from nonRiemannian volume forms
Abstract
We propose a simple modified gravity model without any initial matter fields in terms of several alternative nonRiemannian spacetime volume elements within the metric (second order) formalism. We show how the nonRiemannian volumeelements, when passing to the physical Einstein frame, create a canonical scalar field and produce dynamically a nontrivial inflationarytype potential for the latter with a large flat region and a stable lowlying minimum. We study the evolution of the cosmological solutions from the point of view of theory of dynamical systems. The theory predicts the spectral index n_s ≈ 0.96 and the tensortoscalar ratio r ≈ 0.002 for 60 efolds, which is in accordance with the observational data. In the future Euclid and SPHEREx missions or the BICEP3 experiment are expected to provide experimental evidence to test those predictions.
 Publication:

European Physical Journal C
 Pub Date:
 September 2019
 DOI:
 10.1140/epjc/s1005201973106
 arXiv:
 arXiv:1906.06691
 Bibcode:
 2019EPJC...79..806B
 Keywords:

 General Relativity and Quantum Cosmology;
 High Energy Physics  Phenomenology;
 High Energy Physics  Theory
 EPrint:
 9 pages, to appear in European Physical Journal C