Robustness of predicted CMB fluctuations in Cartan $F(R)$ gravity

Abstract

The cosmology of the $F(R)$ gravity rebuilding by the Cartan formalism is investigated. This is called Cartan $F(R)$ gravity. The well-known $F(R)$ gravity has been introduced to extend the standard cosmology, e.g. to explain the cosmological accelerated expansion as the inflation. Cartan $F(R)$ gravity is based on the Riemann-Cartan geometry. The curvature $R$ can separate to two parts, one is derived from the Levi-Civita connection and the other from the torsion. Assuming the matter-independent spin connection, we have successfully rewritten the action of Cartan $F(R)$ gravity into the Einstein-Hilbert action and a scalar field with canonical kinetic and potential terms without any conformal transformations. This feature simplifies building and analysis of new model of inflation. In this paper, we study two models, the power-law model and logarithmic model, and evaluate fluctuations in the cosmological microwave background (CMB) radiation. We found the robustness of CMB fluctuation by the analytical computation and confirm this feature by the numerical calculation.

arXiv comment14pages, 4figures

References in corpus (34)

• Unified cosmic history in modified gravity: from F(R) theory to Lorentz non-invariant models
• Introduction to Modified Gravity and Gravitational Alternative for Dark Energy
• Modified Gravity Theories on a Nutshell: Inflation, Bounce and Late-time Evolution
• Planck 2018 results. X. Constraints on inflation
• Inflation Dynamics and Reheating
• Palatini Approach to Modified Gravity: f(R) Theories and Beyond
• Modified gravity with $\ln R$ terms and cosmic acceleration
• Instant Preheating
• Metric-affine f(R) theories of gravity
• Cosmology with torsion: An alternative to cosmic inflation
• Question of quantum equivalence between Jordan frame and Einstein frame
• Einstein and Jordan frames reconciled: a frame-invariant approach to scalar-tensor cosmology
• Cosmology with a spin
• f(R) Gravity with Torsion: The Metric-Affine Approach
• Dark spinors with torsion in cosmology
• One-loop divergences for gravity non-minimally coupled to a multiplet of scalar fields: calculation in the Jordan frame. I. The main results
• f(R) gravity, torsion and non-metricity
• Consistency relation for $R^p$ inflation
• Torsion/non-metricity duality in f(R) gravity
• Reheating in Constant-roll $F(R)$ Gravity
• The metric-affine formalism of f(R) gravity
• f(R) gravity with torsion: a geometric approach within the J-bundles framework
• Metric-affine $f(R)$-gravity with torsion: an overview
• Meaning of the field dependence of the renormalization scale in Higgs inflation
• Constraint on reheating after f(R) inflation from gravitational waves
• Gravity-induced four-fermion contact interaction implies gravitational intermediate W and Z type gauge bosons
• The Cosmology of Quadratic Torsionful Gravity
• Reheating and particle creation in unimodular f(R, T) gravity
• Imprints from a Riemann-Cartan space-time on the energy levels of Dirac spinors
• The gauge symmetries of f(R) gravity with torsion in the Cartan formalism
• Exploring the inflation of $F(R)$ gravity
• Cartan $F(R)$ Gravity and Equivalent Scalar-Tensor Theory
• Tsallis holographic inflation in $f(R,T)$ gravity: CMB constraints, reheating, and swampland implications
• Reheating constraints in Instant Preheating