Observational signatures of scalar field dynamics in modified $f(Q, L_m)$ gravity
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arXiv
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| Formato: | Preprint |
| Publicado: |
2025
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| author | Samaddar, Amit Singh, S. Surendra |
| author_facet | Samaddar, Amit Singh, S. Surendra |
| contents | We investigate the cosmological implications of a tanh-parametrized scalar field model in the framework of modified $f(Q, L_{m})$ gravity by adopting the form $f(Q, L_{m})=βQ+δL_{m}$ along with a scalar field energy density $ρ_ϕ= ρ_{c0} \tanh(A + Bz)$. Using MCMC methods and combining $31$ cosmic chronometer data points, $15$ BAO, DESI DR2 BAO and $1701$ Pantheon+ samples, we constrain the model parameters and obtain $H_{0}=74.284^{+4.155}_{-4.275}$, $Ω_{m0}=0.326^{+0.093}_{-0.072}$ and $B=-0.001^{+0.030}_{-0.030}$. The model predicts a transition redshift $z_{tr}=0.5914$ and a present deceleration parameter $q_0=-0.5167$, consistent with a Universe transitioning from deceleration to acceleration. We further analyze the evolution of the EoS parameter, density components and statefinder diagnostics in which all parameters show asymptotic convergence to a de Sitter phase. Additionally, we study black hole mass accretion, showing its dependence on the scalar field dynamics. This work highlights the compatibility of tanh-scalar field forms with $f(Q, L_m)$ gravity in describing cosmic acceleration and gravitational phenomena. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2507_08897 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Observational signatures of scalar field dynamics in modified $f(Q, L_m)$ gravity Samaddar, Amit Singh, S. Surendra General Relativity and Quantum Cosmology High Energy Physics - Theory We investigate the cosmological implications of a tanh-parametrized scalar field model in the framework of modified $f(Q, L_{m})$ gravity by adopting the form $f(Q, L_{m})=βQ+δL_{m}$ along with a scalar field energy density $ρ_ϕ= ρ_{c0} \tanh(A + Bz)$. Using MCMC methods and combining $31$ cosmic chronometer data points, $15$ BAO, DESI DR2 BAO and $1701$ Pantheon+ samples, we constrain the model parameters and obtain $H_{0}=74.284^{+4.155}_{-4.275}$, $Ω_{m0}=0.326^{+0.093}_{-0.072}$ and $B=-0.001^{+0.030}_{-0.030}$. The model predicts a transition redshift $z_{tr}=0.5914$ and a present deceleration parameter $q_0=-0.5167$, consistent with a Universe transitioning from deceleration to acceleration. We further analyze the evolution of the EoS parameter, density components and statefinder diagnostics in which all parameters show asymptotic convergence to a de Sitter phase. Additionally, we study black hole mass accretion, showing its dependence on the scalar field dynamics. This work highlights the compatibility of tanh-scalar field forms with $f(Q, L_m)$ gravity in describing cosmic acceleration and gravitational phenomena. |
| title | Observational signatures of scalar field dynamics in modified $f(Q, L_m)$ gravity |
| topic | General Relativity and Quantum Cosmology High Energy Physics - Theory |
| url | https://arxiv.org/abs/2507.08897 |