Resealed Einstein-Hilbert gravity: Inflation and the Swampland criteria

In this work, we shall study a class of f (R, phi) gravity models which during the inflationary era, which is the large curvature regime, result to an effective inflationary Lagrangian that contains a resealed Einstein Hilbert term alpha R in the presence of a canonical minimally coupled scalar field. The dimensionless parameter alpha is chosen to take values in the range 0 < alpha < 1 and the main motivation for studying these resealed Einstein-Hilbert f (R, phi) gravities, is the fact that the resealed action may render an otherwise incompatible canonical scalar field theory with the Swampland criteria, to be compatible with the Swampland criteria and specifically the distance conjecture and the de Sitter conjecture, without considering the refined de Sitter conjecture however. As we will show, by studying a large number of inflationary potentials appearing in the 2018 Planck collaboration paper for the constraints on inflation, the simultaneous compatibility with both the Planck constraints and the aforementioned two Swampland criteria is achieved for some models, and the main characteristic of the models for which this is possible is the small value that the parameter alpha must take.

Automated summary

In this work, a class of f(R,phi) gravity models that result in an effective inflationary Lagrangian with a resealed Einstein-Hilbert term alpha R during the inflationary era is studied. The motivation is to make incompatible canonical scalar field theories compatible with the Swampland criteria, specifically the distance conjecture and the de Sitter conjecture. It is found that some models can simultaneously satisfy the Planck constraints and the two Swampland criteria when the parameter alpha is small.