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arXiv · 2007.12595

Higgs inflation with the Holst and the Nieh-Yan term

Miklos Långvik·Juha-Matti Ojanperä·Sami Raatikainen·Syksy Rasanen
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Abstract

The action of loop quantum gravity includes the Holst term and/or the Nieh-Yan term in addition to the Ricci scalar. These terms are expected to couple non-minimally to the Higgs. Thus the Holst and Nieh-Yan terms contribute to the classical equations of motion, and they can have a significant impact on inflation. We derive inflationary predictions in the parameter space of the non-minimal couplings, including non-minimally coupled terms up to dimension 4. Successful inflation is possible even with zero or negative coupling of the Ricci scalar. Notably, inflation supported by the non-minimally coupled Holst term alone gives almost the same observables as the original metric formulation plateau Higgs inflation. A non-minimally coupled Nieh-Yan term alone cannot give successful inflation. When all three terms are considered, the predictions for the spectral index and tensor-to-scalar ratio span almost the whole range probed by upcoming experiments. This is not true for the running of the spectral index, and many cases are highly tuned.

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Miklos Långvik, Juha-Matti Ojanperä, Sami Raatikainen, Syksy Rasanen. 2020-07-24. Higgs inflation with the Holst and the Nieh-Yan term. https://doi.org/10.1103/physrevd.103.083514

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