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arXiv · 2203.15035

Slow-roll inflation in $f(R,T)$ gravity with a $RT$ mixing term

Che-Yu Chen·Yakefu Reyimuaji·Xinyi Zhang
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Abstract

We consider slow-roll inflationary models in a class of modified theories of gravity which contains non-minimal curvature-inflaton couplings, i.e., the $f(R,T)$ gravity, where $R$ is the Ricci scalar and $T$ is the trace of the inflaton energy-momentum tensor. On top of the minimally coupled $T$ that has been widely investigated in the literature, we further include a $RT$ mixing term in the theory. This mixing term introduces non-minimal derivative couplings and plays an important role in inflationary dynamics. Taking chaotic and natural inflation as examples, we find that the predictions for spectral tilt and the tensor-to-scalar ratio are sensitive to the existence of the $RT$ mixing term. In particular, by turning on this mixing term, it is possible to bring chaotic and natural inflation into better agreement with observational data.

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Che-Yu Chen, Yakefu Reyimuaji, Xinyi Zhang. 2022-03-28. Slow-roll inflation in $f(R,T)$ gravity with a $RT$ mixing term. https://doi.org/10.1016/j.dark.2022.101130

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