Observational constraints on a non-minimally coupled scalar field in non-metricity gravity with an extra degree of freedom
Abstract
We investigate a non-minimally coupled scalar field in non-metricity gravity, adopting a non-trivial connection class in spatially flat FLRW spacetimes. In contrast to the coincident-gauge choice, this connection class activates an additional dynamical degree of freedom (DoF) that modifies the background evolution. We study two representative models, defined by power-law and exponential coupling functions with the exponential potential for scalar field. Confronting both models with recent combined datasets - DESI BAO, two independent supernova compilations, and cosmic chronometers - we find that each reproduces an extended matter-dominated era followed by a stable late-time de-Sitter attractor, with inferred parameters consistent with the standard ΛCDM model. A complementary autonomous dynamical-system analysis identifies a sequence of critical points describing successive stiff-fluid, transient matter-dominated, and stable de-Sitter phases, ensuring a viable thermal history of the universe. The observational and dynamical results are mutually consistent and support the cosmological viability of the proposed models.
Versions
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BibTeX
@misc{hussain2026observational,
title = {{Observational constraints on a non-minimally coupled scalar field in non-metricity gravity with an extra degree of freedom}},
author = {Saddam Hussain and Ghulam Murtaza and Avik De},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.33146},
eprint = {2610.33146},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.33146},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Observational constraints on a non-minimally coupled scalar field in non-metricity gravity with an extra degree of freedom
AU - Saddam Hussain
AU - Ghulam Murtaza
AU - Avik De
PY - 2026
DA - 2026/10/23
PB - arXiv
DO - 10.48550/arxiv.2610.33146
UR - https://arxiv.org/abs/2610.33146
AB - We investigate a non-minimally coupled scalar field in non-metricity gravity, adopting a non-trivial connection class in spatially flat FLRW spacetimes. In contrast to the coincident-gauge choice, this connection class activates an additional dynamical degree of freedom (DoF) that modifies the background evolution. We study two representative models, defined by power-law and exponential coupling functions with the exponential potential for scalar field. Confronting both models with recent combined datasets - DESI BAO, two independent supernova compilations, and cosmic chronometers - we find that each reproduces an extended matter-dominated era followed by a stable late-time de-Sitter attractor, with inferred parameters consistent with the standard ΛCDM model. A complementary autonomous dynamical-system analysis identifies a sequence of critical points describing successive stiff-fluid, transient matter-dominated, and stable de-Sitter phases, ensuring a viable thermal history of the universe. The observational and dynamical results are mutually consistent and support the cosmological viability of the proposed models.
ER -