A new parametric observational study of $f(Q,B)$ gravity with modified chaplygin gas
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| Format: | Preprint |
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2025
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| author | Samaddar, Amit Singh, S. Surendra |
| author_facet | Samaddar, Amit Singh, S. Surendra |
| contents | In this work, we explore the cosmological dynamics of a modified gravity framework based on the function $f(Q,B)=δQ^{2}+βB$, 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 $p=Aρ-\frac{B}{ρ^α}$, 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 $H_0 = 72.22^{+3.64}_{-4.46}$, $A_s = 0.696^{+0.082}_{-0.129}$, $α= 0.0029^{+0.022}_{-0.021}$, and $A = 0.0038^{+0.071}_{-0.047}$. The deceleration parameter transitions at redshift $z_{tr} \approx 0.946$, while the present-day value is $q_0 = -0.789$. The model yields an age of the Universe $t_0 \approx 13.53$ Gyr and a present EoS parameter $ω_0 \approx -0.691$, 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. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2507_14251 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | A new parametric observational study of $f(Q,B)$ gravity with modified chaplygin gas Samaddar, Amit Singh, S. Surendra General Relativity and Quantum Cosmology High Energy Physics - Theory In this work, we explore the cosmological dynamics of a modified gravity framework based on the function $f(Q,B)=δQ^{2}+βB$, 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 $p=Aρ-\frac{B}{ρ^α}$, 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 $H_0 = 72.22^{+3.64}_{-4.46}$, $A_s = 0.696^{+0.082}_{-0.129}$, $α= 0.0029^{+0.022}_{-0.021}$, and $A = 0.0038^{+0.071}_{-0.047}$. The deceleration parameter transitions at redshift $z_{tr} \approx 0.946$, while the present-day value is $q_0 = -0.789$. The model yields an age of the Universe $t_0 \approx 13.53$ Gyr and a present EoS parameter $ω_0 \approx -0.691$, 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. |
| title | A new parametric observational study of $f(Q,B)$ gravity with modified chaplygin gas |
| topic | General Relativity and Quantum Cosmology High Energy Physics - Theory |
| url | https://arxiv.org/abs/2507.14251 |