Cosmological implications of f (Q) gravity with a nonlinear equation of state


Özansoy M., Shukla B. K., SOFUOĞLU D., Beesham A., Khare S.

International Journal of Geometric Methods in Modern Physics, 2025 (SCI-Expanded) identifier

  • Yayın Türü: Makale / Tam Makale
  • Basım Tarihi: 2025
  • Doi Numarası: 10.1142/s0219887825502731
  • Dergi Adı: International Journal of Geometric Methods in Modern Physics
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Aerospace Database, Communication Abstracts, Metadex, zbMATH, Civil Engineering Abstracts
  • Anahtar Kelimeler: cosmographic parameters, f (Q) gravity, observational constraints
  • İstanbul Üniversitesi Adresli: Evet

Özet

In this work, we investigate the cosmological implications of f(Q) gravity by introducing a nonlinear equation of state of the form p = βρ2 - ρ. This modified gravity framework, based on the non-metricity scalar Q, offers an alternative to General Relativity and provides new insights into cosmic acceleration. To test the validity of our model, we use a combined observational dataset consisting of 31 cosmic chronometer data points, 1701 Type Ia supernova measurements, and 26 baryon acoustic oscillation observations, leading to a total of 1758 data points. The statistical analysis based on this dataset allows for a viable comparison with the standard ΛCDM model. We analyze cosmographic parameters such as the deceleration parameter, jerk parameter, and statefinder parameters, to determine the impact of the model on the evolution of the universe. The results indicate that our model successfully describes cosmic expansion while presenting deviations from the standard ΛCDM scenario. Statistical comparisons based on the Akaike Information Criterion (AIC) and Bayesian Information Criterion (BIC) further suggest that the proposed model provides a competitive fit to observational data. Our findings show the potential of f(Q) gravity with a nonlinear EoS in the quadratic form as an alternative to the ΛCDM model. This work contributes to efforts to explore modified gravity theories as possible explanations for late cosmic acceleration and provides commentary on their implications.