Cosmology with Scalar-Euler form Coupling

Abstract

A coupling between the spacetime geometry and a scalar field involving the Euler four-form can have important consequences in General Relativity. The coupling is a four-dimensional version of the Jackiw-Teitelboim action, in which a scalar couples to the Euler two-form in two dimensions. In this case the first order formalism, in which the vierbein (or the metric) and the spin connection (or the afine connection) are varied independently, is not equivalent to the second order one, in which the geometry is completely determined by the metric. This is because the torsion postulate (T=0) is not valid and one cannot algebraically solve the spin connection from its own field equation. The direct consequence of this obstruction is that the torsion becomes a new source for the metric curvature, and even if the scalar field is very slowly varying over cosmic scales as to have no observable astronomical efects at the galactic scale, it has important dynamical efects that can give rise to a cosmological evolution radically diferent from the standard FRWL model.

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• A unified, purely affine theory of gravitation and electromagnetism

Cited by in corpus (23)

• Big bounce and closed universe from spin and torsion
• Parity violating Friedmann Universes
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• Non-minimally coupled scalar field cosmology with torsion
• A Zero-Parameter Extension of General Relativity with Varying Cosmological Constant
• Nonminimal couplings, gravitational waves, and torsion in Horndeski's theory
• Kaluza-Klein cosmology from five-dimensional Lovelock-Cartan theory
• Luminal Propagation of Gravitational Waves in Scalar-tensor Theories: The Case for Torsion
• Unimodular Einstein--Cartan gravity: Dynamics and conservation laws
• Induced gravitational topological term and the Einstein-Cartan modified theory
• Cosmological signature change in Cartan Gravity with dynamical symmetry breaking
• Some cosmological models coming from gravitational theories having torsional degrees of freedom
• Cosmological Dark Matter Amplification through Dark Torsion
• A black hole solution in conformal supergravity
• Chern-Simons Gravity in Four Dimensions
• A polynomial affine model of gravity: after ten years
• Asymptotically AdS black hole with a conformally-coupled scalar field in the first-order formalism of gravity
• An introduction to the physics of Cartan gravity
• Comments On Torsion and MacDowell-Mansouri gravity
• Five dimensional Chern-Simons Gravity for the expanded (anti)-de Sitter gauge group C${}_5$
• $n+1$ formalism of $f($Lovelock$)$ gravity
• Gauss-Bonnet Gravity in $D=4$ Without Gauss-Bonnet Coupling to Matter - Cosmological Implications
• Torsion as a Gauge Field in a Lorentz-Chern-Simons Theory