BICEP/Keck data and Quadratic Gravity

Abstract

The recent results of the BICEP and Keck collaborations have put stringent bounds on many inflationary models, including some well-motivated ones. This is certainly the case when gravity remains described by Einstein's theory up to the inflationary scale, but can be avoided by introducing quadratic-in-curvature terms that are effective at that scale. Recently it has also been shown that these terms can UV complete gravity respecting stability and unitarity. Here the predictions of such quadratic gravity are computed and compared with the BICEP/Keck constraints by focusing on some of the inflationary scenarios that are best-motivated from the particle physics point of view and are already ruled out in Einstein gravity: (critical) Higgs inflation and natural inflation. The first scenario can be considered as the most economical option as the inflaton is identified with the only known elementary scalar field in the Standard Model and the near criticality of the Standard Model is used to remain in the perturbative regime. In the second one a pseudo-Nambu-Goldstone boson contributes to the inflationary dynamics and its potential is naturally flat. It is shown that in both scenarios one can restore the agreement with the observational constraints in quadratic gravity.

v2: 21 pages, 5 figures, published version

References in corpus (20)

• The Standard Model Higgs boson as the inflaton
• The fate of hints: updated global analysis of three-flavor neutrino oscillations
• BICEP / Keck XIII: Improved Constraints on Primordial Gravitational Waves using Planck, WMAP, and BICEP/Keck Observations through the 2018 Observing Season
• 2020 Global reassessment of the neutrino oscillation picture
• The landscape of QCD axion models
• Higgs inflation: consistency and generalisations
• Power-counting and the Validity of the Classical Approximation During Inflation
• On Inflation with Non-minimal Coupling
• Higgs inflation at the critical point
• Higgs inflation still alive
• Higgs inflation from Standard Model criticality
• Gravitational corrections to Standard Model vacuum decay
• Metastability in Quadratic Gravity
• A Simple Motivated Completion of the Standard Model below the Planck Scale: Axions and Right-Handed Neutrinos
• Softened Gravity and the Extension of the Standard Model up to Infinite Energy
• Dimensional Transmutation in Gravity and Cosmology
• Predictions of quantum gravity in inflationary cosmology: effects of the Weyl-squared term
• Natural-Scalaron Inflation
• Axion-Sterile-Neutrino Dark Matter
• Hearing Higgs with Gravitational Wave Detectors

Cited by in corpus (21)

• Slow-roll inflation in $f(R,T)$ gravity with a $RT$ mixing term
• A non-Perturbative and Background-Independent Formulation of Quadratic Gravity
• Probing Quadratic Gravity with the Event Horizon Telescope
• Generalized non-local $R^2$-like inflation
• Natural Inflation with non minimal coupling to gravity in $R^2$ gravity under the Palatini formalism
• Natural Metric-Affine Inflation
• Visions in Quantum Gravity
• Inflation with Massive Spin-2 Ghosts
• Natural Inflation with Exponentially Small Tensor-To-Scalar Ratio
• (Multi-field) Natural Inflation and Gravitational Waves
• Unimodular Quadratic Gravity and the Cosmological Constant
• Lectures in Quantum Gravity
• Introduction to Thermal Field Theory: From First Principles to Applications
• Unitarity through PT symmetry in Quantum Quadratic Gravity
• Precision predictions of Starobinsky inflation with self-consistent Weyl-squared corrections
• Natural inflation in Palatini $F(R,X)$
• Slow-roll inflation in $f\left(R,T,R_{ab}{T}^{ab}\right)$ gravity
• Primordial Gravitational Waves in Quadratic Gravity
• Strict renormalizability as a paradigm for fundamental physics
• Natural inflation in Palatini $F(R)$
• Inflationary scenarios beyond the Standard Model