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PreprintarXiv licencearXiv

Natural Metric-Affine Inflation: Reloaded

  • D. Kraiko
  • A. Racioppi
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Abstract

We revisit natural inflation within the framework of metric-affine gravity, considering the impact of a periodic non-minimal coupling between the inflaton and the Nieh-Yan term. Such a term, alone, leads to linear inflation predictions in the strong coupling limit and cannot help to rescue the natural inflation scenario. However, once an analogous non-minimal coupling with the Ricci scalar is added, agreement with data can be easily achieved. Remarkably, the scenario remains viable even with a sub-Planckian periodicity scale and relatively small (order of one) non-minimal couplings.

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Cite

BibTeXRIS
BibTeX
@misc{kraiko2026natural,
  title = {{Natural Metric-Affine Inflation: Reloaded}},
  author = {D. Kraiko and A. Racioppi},
  howpublished = {arXiv},
  year = {2026},
  month = oct,
  doi = {10.48550/arxiv.2605.23827},
  eprint = {2605.23827},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2605.23827},
}
RIS
TY  - UNPB
TI  - Natural Metric-Affine Inflation: Reloaded
AU  - D. Kraiko
AU  - A. Racioppi
PY  - 2026
DA  - 2026/10/05
PB  - arXiv
DO  - 10.48550/arxiv.2605.23827
UR  - https://arxiv.org/abs/2605.23827
AB  - We revisit natural inflation within the framework of metric-affine gravity, considering the impact of a periodic non-minimal coupling between the inflaton and the Nieh-Yan term. Such a term, alone, leads to linear inflation predictions in the strong coupling limit and cannot help to rescue the natural inflation scenario. However, once an analogous non-minimal coupling with the Ricci scalar is added, agreement with data can be easily achieved. Remarkably, the scenario remains viable even with a sub-Planckian periodicity scale and relatively small (order of one) non-minimal couplings.
ER  -