2024/11/14 by Amit Samaddar, Samaddar, Amit, S. Surendra Singh +1
Earth and Planetary Sciences · Physics and Astronomy · #Black Holes and Theoretical Physics #Cosmology and Gravitation Theories #FOS: Physical sciences #General Relativity and Quantum Cosmology (gr-qc) #Geophysics and Gravity Measurements #High Energy Physics - Theory (hep-th)
paper · pdf · doi:10.48550/arxiv.2411.17754
openalex publication_date 2024/11/14 · openalex created_date 2024/12/05 · openalex updated_date 2026/07/28
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=ω0+ω1z, ω=ω0+\fracω1z(1+z)1+z2 and ω=ω0+\fracω1z21+z2 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 ΛCDM showing slight deviations consistent with recent observations. Sound speed analysis demonstrates the physical stability of all parameterizations.