Searcharxiv⌕ Search
Home/Archive/arXiv

arXiv · 2603.29337

Accelerating Cosmological Model with Scalar Field in $f(R,\mathcal{L}_{m})$ Gravity

Y. Kalpana Devi·Rahul Bhagat·B. Mishra
View original source ↗Read source document ↗Export metadata ↓

Abstract

In this work, we investigate the cosmological dynamics of $f(R,\mathcal{L}_m)$ gravity using two complementary scenarios: without a scalar field and with a minimally coupled generalized scalar field. For the case without a scalar field, we consider a functional form with linear and exponential dependence on the matter Lagrangian and perform a dynamical system analysis. The resulting autonomous system admits a matter-dominated saddle configuration and a de Sitter attractor . Due to the non-hyperbolic nature of the critical curves, Center Manifold Theory (CMT) is employed to establish the local asymptotic stability of the de Sitter solution. We then extend the framework by including a minimally coupled generalized scalar field with an exponential self-interacting potential. The extended autonomous system also contains a matter-dominated saddle point and a stable dark-energy-dominated attractor corresponding to a late-time de Sitter phase. The stability of the attractor is confirmed through CMT, and the evolution of the cosmological parameters demonstrates a smooth transition from a matter-dominated decelerating era to accelerated. Also, in the absence of the scalar field, the matter-dominated configuration associated with a vanishing nonlinear contribution remains stable, whereas the inclusion of the scalar field transforms the matter era into a saddle configuration, thereby enabling the Universe to naturally evolve toward the late-time accelerated attractor. In both scenarios, the exponential power term equal to $-1$ corresponds to a late-time de Sitter phase. These results show that both scenarios lead to late-time cosmic acceleration, while the inclusion of the scalar field provides an additional dynamical mechanism for realizing a stable dark-energy-dominated Universe without invoking a cosmological constant.

Explore related subjects

gr-qc

Keep this discovery

BibTeXRIS

Y. Kalpana Devi, Rahul Bhagat, B. Mishra. 2026-03-31. Accelerating Cosmological Model with Scalar Field in $f(R,\mathcal{L}_{m})$ Gravity. https://doi.org/10.1016/j.aop.2026.170597

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Electrovacuum Black Hole Uniqueness

We prove the black hole uniqueness conjecture in the axially symmetric, stationary, electrovacuum setting, subject to the refined asymptotic analysis of the associated singular harmonic maps, which includes an analyticity hypothesis at the axes. More precisely, it is shown that any asymptotically flat solution of the Einstein--Maxwell equations in this class, with more than one black hole horizon component is either: Majumdar--Papapetrou, up to a duality rotation, in which case all logarithmic angle defects vanish, or every finite axis rod logarithmic angle defect is strictly negative and hence every interaction force is strictly attractive. The proof extends the singular harmonic map method used for vacuum Kerr uniqueness in [18].

gr-qc↗
arXiv2026

Constraining Modified Mass-to-Horizon Cosmology Through Primordial Inflationary Observables

We investigate slow-roll inflation in a modified cosmological framework inspired by a generalized mass-to-horizon relation (MHR), $M=\gamma {c^2 L^n}/{G}$, where $n$ is a real parameter and $\gamma$ a dimensional constant. Using Padmanabhan's emergence paradigm, we derive the modified Friedmann equations for a flat FRW universe and analyze the dynamics of a canonical scalar field (inflaton) under the slow-roll approximation. We study the resulting inflationary phenomenology for power-law and Starobinsky potentials. For power-law potentials, the MHR modification fails to reconcile these models with current CMB constraints on $r$ and $n_s$. In contrast, Starobinsky inflation exhibits significant sensitivity to deviations from $n=1$. A perturbative analysis ($n=1+\Delta$) yields corrections to inflationary observables. We observe that the scalar power-spectrum normalization, under a fixed-Starobinsky prescription, imposes the stringent constraint $0.960 \lesssim n \lesssim 1.040$ for $N=60$ efolds. This is considerably tighter than spectral-index bounds. Our results establish inflation, particularly Starobinsky-like models, as a sensitive probe of generalized horizon thermodynamics and departures from standard MHR scaling.

gr-qc↗
arXiv2026

Improving the Sensitivity of Gravitational Wave Detection with Weighted Conformal Prediction

In the last decade, kilometre-scale interferometric gravitational-wave detectors have observed hundreds of compact binary mergers, the majority of which are binary black holes. However, the data are noise-dominated, and multiple independent search algorithms (pipelines) are used to enhance sensitivity and improve robustness. Rather than the standard approach of selecting the most significant pipeline output, we combine the outputs from all pipelines using a conformal prediction-based framework to provide statistically rigorous confidence estimates for candidate events. While combining pipelines improves sensitivity and ranking robustness, it requires a principled statistical framework that remains valid as data properties evolve across observing runs. A key challenge is distribution shifts between simulated datasets used for training and calibration and the real, unlabelled, observations used for testing, which can invalidate coverage guarantees and bias confidence estimates. In this work, we address this challenge by incorporating likelihood-ratio reweighting into our conformal prediction framework to account for covariate shift. Using mock datasets containing simulated signals, we demonstrate that weighted conformal prediction restores well-calibrated coverage under covariate shift and increases the confidence of events near the detection threshold, recovering true signals that would otherwise be missed.

gr-qc↗