Swampland diagnostics and observational tests of the inflationary universe in the Palatini formalism
Abstract
We consider quintessential inflation in a quadratic Palatini model with a generalized Peebles-Vilenkin potential, where the same scalar field describes both the inflationary plateau and the later inverse-power-law regime. Passing to the Einstein frame gives a canonically normalized field and an explicit effective potential. The inflationary predictions are then reassessed, together with the further-refined de Sitter, scalar weak-gravity, strong scalar weak-gravity, distance, and trans-Planckian censorship conjectures. The value of the tensor-to-scalar ratio stays below the observational bounds used in this work, whereas the spectral index of scalar fluctuations changes with the potential exponent and with the duration of inflation. The further-refined de Sitter bound is satisfied only over part of the trajectory. At the pivot, both weak-gravity diagnostics are negative in the reduced-Planck-mass convention, although they become positive at finite field values. The field excursion is super-Planckian, but this does not by itself imply a failure of the distance conjecture; the trans-Planckian censorship criterion is not met in the assumed slow-roll regime.
Related
- Swampland conjectures through ACT observations: Observational signatures of radiative-corrected inflation
- Nucleating an inflationary universe: Euclidean wormholes and their no-boundary limit
- Creation of an inflationary epoch from an Emergent Universe through quantum tunneling
- Entropic Chaplygin-Gas cosmology and late-universe tension diagnostics
- Beating and coupling in pulsating stars: A unified Fourier description and observational diagnostics
BibTeX
@misc{gashti2026swampland,
title = {{Swampland diagnostics and observational tests of the inflationary universe in the Palatini formalism}},
author = {Saeed Noori Gashti and Mohammad Reza Alipour and Mohammad Ali S. Afshar and Kazuharu Bamba},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.28661},
eprint = {2610.28661},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.28661},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Swampland diagnostics and observational tests of the inflationary universe in the Palatini formalism
AU - Saeed Noori Gashti
AU - Mohammad Reza Alipour
AU - Mohammad Ali S. Afshar
AU - Kazuharu Bamba
PY - 2026
DA - 2026/10/13
PB - arXiv
DO - 10.48550/arxiv.2610.28661
UR - https://arxiv.org/abs/2610.28661
AB - We consider quintessential inflation in a quadratic Palatini model with a generalized Peebles-Vilenkin potential, where the same scalar field describes both the inflationary plateau and the later inverse-power-law regime. Passing to the Einstein frame gives a canonically normalized field and an explicit effective potential. The inflationary predictions are then reassessed, together with the further-refined de Sitter, scalar weak-gravity, strong scalar weak-gravity, distance, and trans-Planckian censorship conjectures. The value of the tensor-to-scalar ratio stays below the observational bounds used in this work, whereas the spectral index of scalar fluctuations changes with the potential exponent and with the duration of inflation. The further-refined de Sitter bound is satisfied only over part of the trajectory. At the pivot, both weak-gravity diagnostics are negative in the reduced-Planck-mass convention, although they become positive at finite field values. The field excursion is super-Planckian, but this does not by itself imply a failure of the distance conjecture; the trans-Planckian censorship criterion is not met in the assumed slow-roll regime.
ER -