Late time behavior in $f(R,\mathcal{L}_{m})$ gravity through Gaussian reconstruction and dynamical stability

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Main Authors: Devi, Y. Kalpana, Narawade, S. A., Mishra, B.
Format: Preprint
Published: 2025
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author Devi, Y. Kalpana
Narawade, S. A.
Mishra, B.
author_facet Devi, Y. Kalpana
Narawade, S. A.
Mishra, B.
contents In this paper, we explore modified gravity in the framework of $f(R, \mathcal{L}_m)$ theories by reconstructing the function $f(\mathcal{L}_m)$, where $\mathcal{L}_m = ρ$ is the matter Lagrangian, under the assumption of a pressureless, matter-dominated Universe. Using a non-parametric Gaussian process reconstruction technique applied to Hubble data, we obtain two viable models of $f(\mathcal{L}_m)$ : (i) a power-law model $f_1(\mathcal{L}_m) = α\mathcal{L}_m^{b_1}$ with $b_1 \in [0.018, 0.025]$ and (ii) an exponential model $f_2(\mathcal{L}_m) = α\mathcal{L}_{m0} \left(1 - e^{-b_2 \sqrt{\mathcal{L}_m/\mathcal{L}_{m0}}} \right)$ with $b_2 \in [2.3, 3.0]$. We then fix the parameter values within these reconstructed ranges and analyze the corresponding dynamical systems within the matter-dominated epoch by constructing autonomous equations. Phase-space analysis reveals the presence of stable critical points in both models, suggesting viable cosmic evolution within their domains of validity. Both the models exhibit stable attractor solution at late time, reinforcing their viability in explaining the late time cosmic acceleration without explicitly invoking a cosmological constant. Our results indicate that $f(R, \mathcal{L}_m)$ gravity with data-driven matter-sector modifications can offer a compelling alternative description of cosmic dynamics during the matter-dominated era.
format Preprint
id arxiv_https___arxiv_org_abs_2506_09568
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Late time behavior in $f(R,\mathcal{L}_{m})$ gravity through Gaussian reconstruction and dynamical stability
Devi, Y. Kalpana
Narawade, S. A.
Mishra, B.
General Relativity and Quantum Cosmology
In this paper, we explore modified gravity in the framework of $f(R, \mathcal{L}_m)$ theories by reconstructing the function $f(\mathcal{L}_m)$, where $\mathcal{L}_m = ρ$ is the matter Lagrangian, under the assumption of a pressureless, matter-dominated Universe. Using a non-parametric Gaussian process reconstruction technique applied to Hubble data, we obtain two viable models of $f(\mathcal{L}_m)$ : (i) a power-law model $f_1(\mathcal{L}_m) = α\mathcal{L}_m^{b_1}$ with $b_1 \in [0.018, 0.025]$ and (ii) an exponential model $f_2(\mathcal{L}_m) = α\mathcal{L}_{m0} \left(1 - e^{-b_2 \sqrt{\mathcal{L}_m/\mathcal{L}_{m0}}} \right)$ with $b_2 \in [2.3, 3.0]$. We then fix the parameter values within these reconstructed ranges and analyze the corresponding dynamical systems within the matter-dominated epoch by constructing autonomous equations. Phase-space analysis reveals the presence of stable critical points in both models, suggesting viable cosmic evolution within their domains of validity. Both the models exhibit stable attractor solution at late time, reinforcing their viability in explaining the late time cosmic acceleration without explicitly invoking a cosmological constant. Our results indicate that $f(R, \mathcal{L}_m)$ gravity with data-driven matter-sector modifications can offer a compelling alternative description of cosmic dynamics during the matter-dominated era.
title Late time behavior in $f(R,\mathcal{L}_{m})$ gravity through Gaussian reconstruction and dynamical stability
topic General Relativity and Quantum Cosmology
url https://arxiv.org/abs/2506.09568