Constraining f(R) gravity and evolving dark energy via large-scale structure and phase-space trajectories
Abstract
We present a joint observational analysis confronting viable f(R) modified gravity theories, specifically the Hu \& Sawicki and Starobinsky models, with background and large-scale structure (LSS) data. Utilizing Monte-Carlo Markov chain (MCMC) sampling across datasets including baryon acoustic oscillations (BAO), type Ia supernovae (SNeIa), cosmic microwave background (CMB) distance priors, and linear growth measurements (fσ8, f, σ8), we place tight constraints on the model parameters governing deviations from General Relativity. For the full dataset combination, we obtain log10 bHS = −6.325−1.138+1.216 for the Hu \& Sawicki model and bS = (0.8±61.0)×10−4 for the Starobinsky model. Model comparison based on the Akaike Information Criterion indicates that these f(R) extensions are statistically favored over flat ΛCDM (|ΔAIC| ≥ 3.99) for the combined data. However, when considering the Bayesian Information Criterion, the evidence for support is significantly reduced. Furthermore, we construct two-dimensional phase-space diagrams in the $(μ, γ)$ and $(μ, Σ)$ planes across several redshifts, establishing a novel diagnostic null-test allowing us to probe for deviations from ΛCDM, corresponding to the fixed point (1,1) in both planes, using LSS observables. Should future weak-lensing and galaxy surveys provide data points with μ−1<0 and γ−1>1 or $Σ-1 < 0 $, then the aforementioned models could be directly ruled out.
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BibTeX
@misc{mathibela2026constraining,
title = {{Constraining $f(R)$ gravity and evolving dark energy via large-scale structure and phase-space trajectories}},
author = {Tshepo Mathibela and Alvaro de la Cruz-Dombriz and Savvas Nesseris},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.10651},
eprint = {2609.10651},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.10651},
}
RIS
TY - UNPB
TI - Constraining f(R) gravity and evolving dark energy via large-scale structure and phase-space trajectories
AU - Tshepo Mathibela
AU - Alvaro de la Cruz-Dombriz
AU - Savvas Nesseris
PY - 2026
DA - 2026/09/09
PB - arXiv
DO - 10.48550/arxiv.2609.10651
UR - https://arxiv.org/abs/2609.10651
AB - We present a joint observational analysis confronting viable f(R) modified gravity theories, specifically the Hu \& Sawicki and Starobinsky models, with background and large-scale structure (LSS) data. Utilizing Monte-Carlo Markov chain (MCMC) sampling across datasets including baryon acoustic oscillations (BAO), type Ia supernovae (SNeIa), cosmic microwave background (CMB) distance priors, and linear growth measurements (fσ_8, f, σ_8), we place tight constraints on the model parameters governing deviations from General Relativity. For the full dataset combination, we obtain log_10 b_HS = −6.325_−1.138^+1.216 for the Hu \& Sawicki model and b_S = (0.8±61.0)×10^−4 for the Starobinsky model. Model comparison based on the Akaike Information Criterion indicates that these f(R) extensions are statistically favored over flat ΛCDM (|ΔAIC| ≥ 3.99) for the combined data. However, when considering the Bayesian Information Criterion, the evidence for support is significantly reduced. Furthermore, we construct two-dimensional phase-space diagrams in the $(μ, γ)$ and $(μ, Σ)$ planes across several redshifts, establishing a novel diagnostic null-test allowing us to probe for deviations from ΛCDM, corresponding to the fixed point (1,1) in both planes, using LSS observables. Should future weak-lensing and galaxy surveys provide data points with μ−1<0 and γ−1>1 or $Σ-1 < 0 $, then the aforementioned models could be directly ruled out.
ER -