UV completion of the Starobinsky model, tensor-to-scalar ratio, and constraints on non-locality

Abstract

In this paper, we build upon the successes of the ultraviolet (UV) completion of the Starobinsky model of inflation. This involves an extension of the Einstein-Hilbert term by an infinite covariant derivative theory of gravity, which is quadratic in curvature. It has been shown that such a theory can potentially resolve the cosmological singularity for a flat, homogeneous and isotropic geometry, and now it can also provide a successful cosmological inflation model, which in the infrared matches all the predictions of the Starobinsky model of inflation. The aim of this note is to show that the tensor-to-scalar ratio is modified by the scale of non-locality, and in general a wider range of tensor-to-scalar ratios can be obtained in this class of model, which can put a lower bound on the scale of non-locality for the first time as large as the O$(10^{14})$ GeV.

7 pages, 1 figure

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Cited by in corpus (13)

• Palatini quadratic gravity: spontaneous breaking of gauged scale symmetry and inflation
• Weyl $R^2$ inflation with an emergent Planck scale
• Nonlocal star as a blackhole mimicker
• Higher-order modified Starobinsky inflation
• $f\left(R,{\nabla }_{{\mu }_1}R,\dots ,{\nabla }_{{\mu }_1}\dots {\nabla }_{{\mu }_n}R\right)$ theories of gravity in Einstein frame: A higher order modified Starobinsky inflation model in the Palatini approach
• Newtonian Potential and Geodesic Completeness in Infinite Derivative Gravity
• Revealing Infinite Derivative Gravity's true potential: The weak-field limit around de Sitter backgrounds
• Hamiltonian Analysis for Infinite Derivative Field Theories and Gravity
• Conditions for defocusing around more general metrics in Infinite Derivative Gravity
• Second-order corrections to Starobinsky inflation
• Gravitational radiation in Infinite Derivative Gravity and connections to Effective Quantum Gravity
• Criteria for resolving the cosmological singularity in Infinite Derivative Gravity around expanding backgrounds
• A Covariant Curvature-History Field Formulation for State-Dependent Infinite-Derivative Gravity