Constraining model parameters in f(Q,C) gravity: Observational analysis and geometric diagnostics

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Autori principali: Samaddar, Amit, Singh, S. Surendra
Natura: Preprint
Pubblicazione: 2024
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author Samaddar, Amit
Singh, S. Surendra
author_facet Samaddar, Amit
Singh, S. Surendra
contents We investigate the cosmological implications of $f(Q,C)$ gravity with $f(Q,C)=αQ+βC$, where $Q$ is the non-metricity scalar and $C$ encapsulates cosmological expansion terms. Three parameterizations of the EoS for dark energy, $ω=ω_{0}+ω_{1}z$, $ω=ω_{0}+\frac{ω_{1}z(1+z)}{1+z^{2}}$ and $ω=ω_{0}+\frac{ω_{1}z^{2}}{1+z^{2}}$ are tested using the Hubble, Hubble plus BAO, and Hubble plus BAO plus Pantheon datasets to constrain model parameters. The resulting Hubble and deceleration parameters reveal a transition from deceleration to acceleration, supporting current cosmic acceleration observations. Analysis of the energy density and pressure confirms positive energy density and a negative pressure for dark energy, potentially driving the late-time acceleration. We examine energy conditions, showing compliance with NEC, WEC and DEC, while SEC remains negative, supporting an accelerated expansion. Statefinder diagnostics suggest that two of the EoS parameterizations lead to Quintessence-like behavior with a time-varying dark energy component, while the third closely approaches $Λ$CDM showing slight deviations consistent with recent observations. Sound speed analysis demonstrates the physical stability of all parameterizations.
format Preprint
id arxiv_https___arxiv_org_abs_2411_17754
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Constraining model parameters in f(Q,C) gravity: Observational analysis and geometric diagnostics
Samaddar, Amit
Singh, S. Surendra
General Relativity and Quantum Cosmology
High Energy Physics - Theory
We investigate the cosmological implications of $f(Q,C)$ gravity with $f(Q,C)=αQ+βC$, where $Q$ is the non-metricity scalar and $C$ encapsulates cosmological expansion terms. Three parameterizations of the EoS for dark energy, $ω=ω_{0}+ω_{1}z$, $ω=ω_{0}+\frac{ω_{1}z(1+z)}{1+z^{2}}$ and $ω=ω_{0}+\frac{ω_{1}z^{2}}{1+z^{2}}$ are tested using the Hubble, Hubble plus BAO, and Hubble plus BAO plus Pantheon datasets to constrain model parameters. The resulting Hubble and deceleration parameters reveal a transition from deceleration to acceleration, supporting current cosmic acceleration observations. Analysis of the energy density and pressure confirms positive energy density and a negative pressure for dark energy, potentially driving the late-time acceleration. We examine energy conditions, showing compliance with NEC, WEC and DEC, while SEC remains negative, supporting an accelerated expansion. Statefinder diagnostics suggest that two of the EoS parameterizations lead to Quintessence-like behavior with a time-varying dark energy component, while the third closely approaches $Λ$CDM showing slight deviations consistent with recent observations. Sound speed analysis demonstrates the physical stability of all parameterizations.
title Constraining model parameters in f(Q,C) gravity: Observational analysis and geometric diagnostics
topic General Relativity and Quantum Cosmology
High Energy Physics - Theory
url https://arxiv.org/abs/2411.17754