Cosmic Expansion in f(Q,C) Gravity: Observational Constraints and Geometric Diagnostics
Abstract
We investigate the late-time expansion history of the Universe within the framework of $f(Q, C)$ gravity by adopting a linear parametrization of the deceleration parameter q(z) = α+βH, where Q denotes the non-metricity scalar and C represents the associated boundary term satisfying the geometrical relation mathringR= Q+C. The adopted parametrization provides a phenomenological description of the cosmic expansion while retaining analytical tractability, allowing the transition from decelerated to accelerated expansion to be examined directly. An exact integration of the corresponding differential equation yields the closed-form Hubble function, H(z)=1/(β[F0−ln(1+z)]), thereby providing an explicit description of the expansion history in terms of redshift. Here F=1/β√(2βt+b) and F0 specifies the value of F at the present epoch. The model parameters are constrained using recent Cosmic Chronometer (CC) measurements, DESI DR2 Baryon Acoustic Oscillation (BAO) observations, Pantheon+SH0ES Type Ia supernovae, and the Union3 observations through Bayesian Markov Chain Monte Carlo (MCMC) analysis. Individual and combined datasets are compared to assess the model's consistency, while its cosmic evolution is examined using the deceleration, the equation-of-state parameter, the state-finder pair r,s, and the Om diagnostic.
Related
- Constraints on Rastall gravity from current observational data
- Observational constraints on a non-minimally coupled scalar field in non-metricity gravity with an extra degree of freedom
- Hybrid Expansion Cosmology in f(T) Gravity: Late-Time Evolution and Observational Bounds
- Observational constraints on Diffusion Cosmologies in Unimodular Gravity from DESI DR2
- Modified Gravity Framework for the Woods-Saxon Inflation: Theoretical Foundations and Observational Constraints
BibTeX
@misc{jena2026cosmic,
title = {{Cosmic Expansion in f(Q,C) Gravity: Observational Constraints and Geometric Diagnostics}},
author = {Rajalaxmi Jena and Sankarsan Tarai},
howpublished = {arXiv},
year = {2026},
month = nov,
doi = {10.48550/arxiv.2611.03689},
eprint = {2611.03689},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2611.03689},
}
RIS
TY - UNPB
TI - Cosmic Expansion in f(Q,C) Gravity: Observational Constraints and Geometric Diagnostics
AU - Rajalaxmi Jena
AU - Sankarsan Tarai
PY - 2026
DA - 2026/11/01
PB - arXiv
DO - 10.48550/arxiv.2611.03689
UR - https://arxiv.org/abs/2611.03689
AB - We investigate the late-time expansion history of the Universe within the framework of $f(Q, C)$ gravity by adopting a linear parametrization of the deceleration parameter q(z) = α+βH, where Q denotes the non-metricity scalar and C represents the associated boundary term satisfying the geometrical relation mathringR= Q+C. The adopted parametrization provides a phenomenological description of the cosmic expansion while retaining analytical tractability, allowing the transition from decelerated to accelerated expansion to be examined directly. An exact integration of the corresponding differential equation yields the closed-form Hubble function, H(z)=1/(β[F_0−ln(1+z)]), thereby providing an explicit description of the expansion history in terms of redshift. Here F=1/β√(2βt+b) and F_0 specifies the value of F at the present epoch. The model parameters are constrained using recent Cosmic Chronometer (CC) measurements, DESI DR2 Baryon Acoustic Oscillation (BAO) observations, Pantheon+SH0ES Type Ia supernovae, and the Union3 observations through Bayesian Markov Chain Monte Carlo (MCMC) analysis. Individual and combined datasets are compared to assess the model's consistency, while its cosmic evolution is examined using the deceleration, the equation-of-state parameter, the state-finder pair r,s, and the Om diagnostic.
ER -