Metric-affine gravity and inflation

Keigo Shimada, Katsuki Aoki, Keiichi Maeda

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

We classify the metric-affine theories of gravitation, in which the metric and the connections are treated as independent variables, by use of several constraints on the connections. Assuming the Einstein-Hilbert action, we find that the equations for the distortion tensor (torsion and non-metricity) become algebraic, which means that those variables are not dynamical. As a result, we can rewrite the basic equations in the form of Riemannian geometry. Although all classified models recover the Einstein gravity in the Palatini formalism (in which we assume there is no coupling between matter and the connections), but when matter field couples to the connections, the effective Einstein equations include an additional hyper energy-momentum tensor obtained from the distortion tensor. Assuming a simple extension of a minimally coupled scalar field in metric-affine gravity, we analyze an inflationary scenario. Even if we adopt a chaotic inflation potential, certain parameters could satisfy observational constraints. Furthermore, we find that a simple form of Galileon scalar field in metric-affine could cause G-inflation.

Original languageEnglish
Article number104020
JournalPhysical Review D
Volume99
Issue number10
DOIs
Publication statusPublished - 2019 May 15

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tensors
gravitation
scalars
Einstein equations
torsion
kinetic energy
formalism
causes
geometry

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

Cite this

Metric-affine gravity and inflation. / Shimada, Keigo; Aoki, Katsuki; Maeda, Keiichi.

In: Physical Review D, Vol. 99, No. 10, 104020, 15.05.2019.

Research output: Contribution to journalArticle

Shimada, Keigo ; Aoki, Katsuki ; Maeda, Keiichi. / Metric-affine gravity and inflation. In: Physical Review D. 2019 ; Vol. 99, No. 10.
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