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arXiv · 1408.5344

Emergent Cosmology, Inflation and Dark Energy

Eduardo Guendelman·Ramón Herrera·Pedro Labraña·Emil Nissimov·Svetlana Pacheva
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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.

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Eduardo Guendelman, Ramón Herrera, Pedro Labraña, Emil Nissimov, Svetlana Pacheva. 2014-08-22. Emergent Cosmology, Inflation and Dark Energy. https://doi.org/10.1007/s10714-015-1852-1

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