A new parametric study of f(Q, B) gravity with modified Chaplygin gas and recent observations

Amit Samaddar; S. Surendra Singh

doi:10.1140/epjc/s10052-025-15086-w

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2024 Impact factor 4.8

Particles and Fields

Open Access

Eur. Phys. J. C (2025) 85: 1357
https://doi.org/10.1140/epjc/s10052-025-15086-w

Regular Article - Theoretical Physics

A new parametric study of f(Q, B) gravity with modified Chaplygin gas and recent observations

Amit Samaddar^a and S. Surendra Singh

Department of Mathematics, National Institute of Technology Manipur, 795004, Imphal, India

^a samaddaramit4@gmail.com

Received: 30 July 2025
Accepted: 15 November 2025
Published online: 25 November 2025

Abstract

In this work, we explore the cosmological dynamics of a modified gravity framework based on the function $f (Q, B) = δ Q^{2} + β B$ $f(Q,B)=\delta Q^{2}+\beta B$ , where Q denotes the nonmetricity scalar and B is the boundary term that relates Q to the Ricci scalar. The matter sector is modeled using the Modified Chaplygin Gas (MCG) with the equation of state $p = A ρ - \frac{D_{1}}{ρ^{α}}$ $p=A\rho -\frac{D_{1}}{\rho ^{\alpha }}$ , allowing the model to interpolate between early-time matter behavior and late-time cosmic acceleration. By deriving an analytical expression for the Hubble parameter H(z), we perform a parameter estimation using Markov Chain Monte Carlo (MCMC) techniques in conjunction with the latest cosmological observations: 46 Hubble parameter measurements, 15 BAO data points, DESI DR2 BAO data and the Pantheon+ Type Ia supernovae compilation. The best-fit values are obtained as $H_{0} = 72 . 2814_{- 4.5209}^{+ 3.4702}$ $H_0=72.2814^{+3.4702}_{-4.5209}$ km/s/Mpc, $A_{s} = 0 . 6964_{- 0.1258}^{+ 0.0779}$ $A_s = 0.6964^{+0.0779}_{-0.1258}$ , $α = 0 . 0027_{- 0.0209}^{+ 0.0225}$ $\alpha = 0.0027^{+0.0225}_{-0.0209}$ and $A = 0 . 0024_{- 0.0464}^{+ 0.0702}$ $A = 0.0024^{+0.0702}_{-0.0464}$ . The deceleration parameter transitions at redshift $z_{tr} \approx 0.946$ $z_{tr} \approx 0.946$ , while the present-day value is $q_{0} = - 0.789$ $$q_0 = -0.789$$ . The model yields an age of the Universe $t_{0} \approx 13.53$ $t_0 \approx 13.53$ Gyr and a present EoS parameter $ω_{0} \approx - 0.691$ $\omega _0 \approx -0.691$ , which reflects the late-time acceleration consistent with observational bounds. These results demonstrate that the MCG scenario within f(Q, B) gravity provides a viable and observationally consistent framework for explaining the late-time accelerated expansion of the Universe.

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.

Funded by SCOAP³.

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