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arXiv · 0807.0069

Inflation in $R + R^2$ Gravity with Torsion

Chih-Hung Wang·Yu-Huei Wu
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Abstract

We examine an inflationary model in $R + R^2$ gravity with torsion, where $R^2$ denotes five independent quadratic curvature invariants; it turns out that only two free parameters remain in this model. We show that the behavior of the scale factor $a(t)$ is determined by two scalar fields, axial torsion $χ(t)$ and the totally anti-symmetric curvature $E(t)$, which satisfy two first-order differential equations. Considering $\dotχ\approx 0$ during inflation leads to a power-law inflation: $a \sim (t+ A)^p$ where $1< p \leq 2 $, and the constant $A$ is determined by the initial values of $E$, $χ$ and the two parameters. After the end of inflation, $χ$ and $E$ will enter into an oscillatory phase.

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Chih-Hung Wang, Yu-Huei Wu. 2009-02-06. Inflation in $R + R^2$ Gravity with Torsion. https://doi.org/10.1088/0264-9381%2F26%2F4%2F045016

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