Emergent Cosmology, Inflation and Dark Energy

Abstract

A new class of gravity-matter models defined in terms of two independent non-Riemannian volume forms (alternative generally covariant integration measure densities) on the space-time manifold are studied in some detail. These models involve an additional $R^2$ (square of the scalar curvature) term as well as scalar matter field potentials of appropriate form so that the pertinent action is invariant under global Weyl-scale symmetry. Scale invariance is spontaneously broken upon integration of the equations of motion for the auxiliary volume-form degrees of freedom. After performing transition to the physical Einstein frame we obtain: (i) An effective potential for the scalar field with two flat regions which allows for a unified description of both early universe inflation as well as of present dark energy epoch; (ii) For a definite parameter range the model possesses a non-singular "emergent universe" solution which describes an initial phase of evolution that precedes the inflationary phase; (iii) For a reasonable choice of the parameters the present model conforms to the Planck Collaboration data.

v.1 14 pages, 2 figures; v.2 references and acknowledgements added; v.3 very significant upgrade - 24 pages, change of list of authors, two new sections, extended abstract, introduction and conclusions, additional citations and acknowledgements; v.4 title shortened, further improvements, version to appear in "General Relativity and Gravitation"

References in corpus (7)

• Observational Signatures and Non-Gaussianities of General Single Field Inflation
• Perturbations in generalized multi-field inflation
• Emergent Universe with Exotic Matter
• A two measure model of dark energy and dark matter
• Scale Symmetry Breaking From Total Derivative Densities and the Cosmological Constant Problem
• Instability of an emergent universe
• Metric-Independent Measures for Supersymmetric Extended Object Theories on Curved Backgrounds

Cited by in corpus (12)

• Quintessential Inflation from Lorentzian Slow Roll
• Cosmological aspects of a unified dark energy and dust dark matter model
• Broken Scale Invariance, Gravity Mass, and Dark Energy in Modified Einstein Gravity with Two Measure Finsler Like Variables
• Quintessential Inflation with Dynamical Higgs Generation as an Affine Gravity
• Radiation Like Scalar Field and Gauge Fields in Cosmology for a theory with Dynamical Time
• Cosmology from multimeasure multifield model
• Bouncing Cosmology in Fourth-Order Gravity
• Constraining the quintessential $\alpha$-attractor inflation through dynamical horizon exit method
• Brane world creation from flat or almost flat space in dynamical tension string theories
• Does diffusion mechanism favor the emergent scenario of the universe?
• Cosmological Singularities in Brane Gravity
• Light Like Segment Compactification and Braneworlds with Dynamical String Tension