Higgs inflation with the Holst and the Nieh-Yan term
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.
Keywords
Cite
@article{arxiv.2007.12595,
title = {Higgs inflation with the Holst and the Nieh-Yan term},
author = {Miklos Långvik and Juha-Matti Ojanperä and Sami Raatikainen and Syksy Rasanen},
journal= {arXiv preprint arXiv:2007.12595},
year = {2021}
}
Comments
16+9 pages, 1 figure. Corrected typos and one figure, added references and explanations. Published version