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arXiv · 1605.02461

Inflationary cosmology in unimodular $F(T)$ gravity

Kazuharu Bamba·Sergei D. Odintsov·Emmanuel N. Saridakis
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Abstract

We investigate the inflationary realization in the context of unimodular $F(T)$ gravity, which is based on the $F(T)$ modification of teleparallel gravity, in which one imposes the unimodular condition through the use of Lagrange multipliers. We develop the general reconstruction procedure of the $F(T)$ form that can give rise to a given scale-factor evolution, and then we apply it in the inflationary regime. We extract the Hubble slow-roll parameters that allow us to calculate various inflation-related observables, such as the scalar spectral index and its running, the tensor-to-scalar ratio, and the tensor spectral index. Then, we examine the particular cases of de Sitter and power-law inflation, of Starobinsky inflation, as well as inflation in a specific model of unimodular $F(T)$ gravity. As we show, in all cases the predictions of our scenarios are in a very good agreement with Planck observational data. Finally, inflation in unimodular $F(T)$ gravity has the additional advantage that it always allows for a graceful exit for specific regions of the model parameters.

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Kazuharu Bamba, Sergei D. Odintsov, Emmanuel N. Saridakis. 2017-05-27. Inflationary cosmology in unimodular $F(T)$ gravity. https://doi.org/10.1142/s0217732317501140

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