Axio-Dilaton Dark Energy: A Dynamical Systems and Bayesian Inference Analysis
Abstract
We initiate a systematic cosmological investigation of an axio-dilaton system governed by a curved field-space metric as generically motivated by supergravity and string compactifications. The scalar sector consists of a light scalar dilaton field evolving along an asymptotically exponential potential and a pseudoscalar field spanning an essentially flat direction, kinetically coupled through an exponential field-space metric. Deviations from the asymptotic regime are incorporated by introducing a generalised Albrecht-Skordis potential containing a polynomial factor. Utilising a dynamical systems approach alongside numerical evolution and Bayesian inference, we constrain the model using Type Ia Supernovae (SNe Ia), Baryon Acoustic Oscillations (BAO) and Planck 2018 distance-prior data. We identify a parameter degeneracy indicating that steeper potentials demand stronger field-space kinetic couplings to sustain late-time cosmic acceleration. Finally, a joint likelihood analysis reveals that while the model successfully accounts for dark energy dynamics, it is only slightly statistically favoured over ΛCDM by current observations.
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BibTeX
@misc{ramoshamud2026axiodilaton,
title = {{Axio-Dilaton Dark Energy: A Dynamical Systems and Bayesian Inference Analysis}},
author = {Mario Ramos-Hamud and Gabriela García-Arroyo and Fernando Quevedo and J. Alberto Vázquez},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.22539},
eprint = {2609.22539},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.22539},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Axio-Dilaton Dark Energy: A Dynamical Systems and Bayesian Inference Analysis
AU - Mario Ramos-Hamud
AU - Gabriela García-Arroyo
AU - Fernando Quevedo
AU - J. Alberto Vázquez
PY - 2026
DA - 2026/09/18
PB - arXiv
DO - 10.48550/arxiv.2609.22539
UR - https://arxiv.org/abs/2609.22539
AB - We initiate a systematic cosmological investigation of an axio-dilaton system governed by a curved field-space metric as generically motivated by supergravity and string compactifications. The scalar sector consists of a light scalar dilaton field evolving along an asymptotically exponential potential and a pseudoscalar field spanning an essentially flat direction, kinetically coupled through an exponential field-space metric. Deviations from the asymptotic regime are incorporated by introducing a generalised Albrecht-Skordis potential containing a polynomial factor. Utilising a dynamical systems approach alongside numerical evolution and Bayesian inference, we constrain the model using Type Ia Supernovae (SNe Ia), Baryon Acoustic Oscillations (BAO) and Planck 2018 distance-prior data. We identify a parameter degeneracy indicating that steeper potentials demand stronger field-space kinetic couplings to sustain late-time cosmic acceleration. Finally, a joint likelihood analysis reveals that while the model successfully accounts for dark energy dynamics, it is only slightly statistically favoured over ΛCDM by current observations.
ER -