Attractor Models in Scalar-Tensor Theories of Inflation

Abstract

In this work we study the cosmological attractor models of inflation in connection with certain scalar-tensor theories of gravity, e.g $f(R)$ gravity and Brans-Dicke theory. For some particular choices of the functional degrees of freedom in these theories, one obtains Starobinsky like predictions in the ($n_s$-$r$) observable plane. We have demonstrated that these choices in the Lagrangian density of certain $f(R)$ and Brans-Dicke theories fulfil the condition of the cosmological attractors. That explains why known predictions of $f(R)$ and Brans-Dicke theories in certain cases appear to be the predictions of the much discussed attractor theories. In addition, we did an analysis showing how the predictions of an attractor model is preserved with respect to the variation in the functional freedom of the theory.

12 pages, 5 figures, updated with some clarifications and minor changes, IJMPD accepted version

References in corpus (9)

• The Standard Model Higgs boson as the inflaton
• The Unity of Cosmological Attractors
• Superconformal Symmetry, NMSSM, and Inflation
• Single-field $\alpha$-attractors
• Inflationary $\alpha$-attractors from $F(R)$ Gravity
• COSMOS-$e^{\prime }$- soft Higgsotic attractors
• Disentangling the $f(R)$ - Duality
• $\alpha$-Attractors: Planck, LHC and Dark Energy
• Non-canonical Conformal Attractors for Single Field Inflation

Cited by in corpus (6)

• Frame-dependence of higher-order inflationary observables in scalar-tensor theories
• Nonminimal Coleman--Weinberg Inflation with an $R^2$ term
• Keeping the relation between the Starobinsky model and no-scale supergravity ACTive
• On the Renormalization Group perspective of $\alpha$-attractors
• Study in the noncanonical domain of Goldstone inflation
• Inflationary assessment of $F(\mathcal{R},\tilde{\mathcal{R}})$ Einstein-Cartan models