Noether Symmetry in a Non-Metricity Theory with a Boundary Term: Exact Solutions and Bayesian Cosmological Constraints
Abstract
We investigate the cosmological implications of a power-law $f(Q, B)$ gravity model, where Q denotes the non-metricity scalar and B is the associated boundary term. We employ the Noether symmetry approach to identify the admissible functional form of the gravitational Lagrangian and to obtain the corresponding conserved quantities and exact cosmological solutions. Using the exact solution, we find that for this model parameter condition α+β>3/2, the model exhibits the accelerating phase of the Universe. Furthermore, we have also discussed the model with recent observational data using a Bayesian Markov Chain Monte Carlo analysis. We consider different combinations of Cosmic Chronometers (CC), Pantheon+ \& SH0ES, and DESI DR2 observations to constrain the model parameters and the Hubble constant H0. The inferred value of H0 depends on the adopted dataset combination, ranging from a higher value for the CC+Pantheon+ combination to a lower value for CC+DESI DR2, with the latter yielding H0=67.5+1.4−1.6 km s−1 Mpc−1, consistent with the Planck 2018 CMB-preferred value within the standard ΛCDM framework. The inferred H0 is strongly dataset dependent, spanning the range between the early-Universe and locally calibrated determinations. We further examine the posterior covariance and correlation matrices to identify parameter degeneracies and assess the robustness of the MCMC constraints. The background evolution also exhibits late-time accelerated expansion and remains compatible with the observational constraints. These results demonstrate that the $f(Q, B)$ model provides a viable alternative description of late-time cosmology.
Related
- Observational constraints on a non-minimally coupled scalar field in non-metricity gravity with an extra degree of freedom
- Cosmological vacuum selection in dynamical symmetry breaking at zero vacuum energy
- Cosmological Evolution of the Randall-Sundrum II Model with Running Vacuum: A Special Class of Solutions
- General Spin-1 Dynamics During Inflation: Microcausality Constraints and Cosmological Collider Signals
- Twin Universes and Bimetric Gravity: From Sakharov's Cosmological Symmetry to Modern Speculations on Negative Mass
BibTeX
@misc{vishwakarma2026noether,
title = {{Noether Symmetry in a Non-Metricity Theory with a Boundary Term: Exact Solutions and Bayesian Cosmological Constraints}},
author = {Pooja Vishwakarma and L K Duchaniya and Yu Shi},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.29303},
eprint = {2609.29303},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.29303},
}
RIS
TY - UNPB
TI - Noether Symmetry in a Non-Metricity Theory with a Boundary Term: Exact Solutions and Bayesian Cosmological Constraints
AU - Pooja Vishwakarma
AU - L K Duchaniya
AU - Yu Shi
PY - 2026
DA - 2026/09/24
PB - arXiv
DO - 10.48550/arxiv.2609.29303
UR - https://arxiv.org/abs/2609.29303
AB - We investigate the cosmological implications of a power-law $f(Q, B)$ gravity model, where Q denotes the non-metricity scalar and B is the associated boundary term. We employ the Noether symmetry approach to identify the admissible functional form of the gravitational Lagrangian and to obtain the corresponding conserved quantities and exact cosmological solutions. Using the exact solution, we find that for this model parameter condition α+β>3/2, the model exhibits the accelerating phase of the Universe. Furthermore, we have also discussed the model with recent observational data using a Bayesian Markov Chain Monte Carlo analysis. We consider different combinations of Cosmic Chronometers (CC), Pantheon+ \& SH0ES, and DESI DR2 observations to constrain the model parameters and the Hubble constant H_0. The inferred value of H_0 depends on the adopted dataset combination, ranging from a higher value for the CC+Pantheon+ combination to a lower value for CC+DESI DR2, with the latter yielding H_0=67.5^+1.4_−1.6 km s^−1 Mpc^−1, consistent with the Planck 2018 CMB-preferred value within the standard ΛCDM framework. The inferred H_0 is strongly dataset dependent, spanning the range between the early-Universe and locally calibrated determinations. We further examine the posterior covariance and correlation matrices to identify parameter degeneracies and assess the robustness of the MCMC constraints. The background evolution also exhibits late-time accelerated expansion and remains compatible with the observational constraints. These results demonstrate that the $f(Q, B)$ model provides a viable alternative description of late-time cosmology.
ER -