Dynamically generated inflationary two-field potential via non-Riemannian volume forms

Abstract

We consider a simple model of modified gravity interacting with a single scalar field $\phi$ with weakly coupled exponential potential within the framework of non-Riemannian spacetime volume-form formalism. The specific form of the action is fixed by the requirement of invariance under global Weyl-scale symmetry. Upon passing to the physical Einstein frame we show how the non-Riemannian volume elements create a second canonical scalar field $u$ and dynamically generate a non-trivial two-scalar-field potential $U_{\mathrm{eff}}(u,\phi )$ with two remarkable features: (i) it possesses a large flat region for large $u$ describing a slow-roll inflation; (ii) it has a stable low-lying minimum w.r.t. $(u,\phi )$ representing the dark energy density in the "late universe". We study the corresponding two-field slow-roll inflation and show that the pertinent slow-roll inflationary curve $\phi =\phi (u)$ in the two-field space $(u,\phi )$ has a very small curvature, i.e., $\phi$ changes very little during the inflationary evolution of $u$ on the flat region of $U_{\mathrm{eff}}(u,\phi )$. Explicit expressions are found for the slow-roll parameters which differ from those in the single-field inflationary counterpart. Numerical solutions for the scalar spectral index and the tensor-to-scalar ratio are derived agreeing with the observational data.

arXiv comment13 pages. 2 Fig. arXiv admin note: text overlap with arXiv:1906.06691 , v.2 14 pages, typos corrected, additional explanations

References in corpus (20)

• Unified cosmic history in modified gravity: from F(R) theory to Lorentz non-invariant models
• Modified Gravity Theories on a Nutshell: Inflation, Bounce and Late-time Evolution
• The DESI Experiment Part I: Science,Targeting, and Survey Design
• Scale invariance, new inflation and decaying Lambda terms
• Planck 2018 results. IX. Constraints on primordial non-Gaussianity
• Holographic inflation
• Dynamical measure and field theory models free of the cosmological constant problem
• Superluminous Supernovae from the Dark Energy Survey
• Dark Energy Survey Year 1 results: Detection of Intra-cluster Light at Redshift $\sim$ 0.25
• The Principle of Non-Gravitating Vacuum Energy and some of its consequences
• Unified Dark Energy and Dust Dark Matter Dual to Quadratic Purely Kinetic K-Essence
• Volume elements of spacetime and a quartet of scalar fields
• Absence of the Fifth Force Problem in a Model with Spontaneously Broken Dilatation Symmetry
• Gravity-Assisted Emergent Higgs Mechanism in the Post-Inflationary Epoch
• Two scalar fields inflation from scale-invariant gravity with modified measure
• A New Mechanism of Dynamical Spontaneous Breaking of Supersymmetry
• Dynamically Generated Inflation from Non-Riemannian Volume Forms
• Modified Gravity and Inflaton Assisted Dynamical Generation of Charge Confinement and Electroweak Symmetry Breaking in Cosmology
• Testing Two-Field Inflation
• Wheeler-DeWitt Quantization of Gravity Models of Unified Dark Energy and Dark Matter

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• Unified Dark Energy and Dark Matter from Dynamical Spacetime Cosmology
• Possible relationship between initial conditions for inflation and past geodesic incompleteness of the inflationary spacetime
• Special cases of the Multi-Measure Model -- understanding the prolonged inflation