Kantowski–Sachs perfect fluid cosmological model in R2- Gravity

• Published in: Indian journal of physics 2023, Vol.97 (5), p.1621-1632
• Main Authors: Vinutha, T., Vasavi, K. Venkata, Niharika, K., Satyanarayana, G.
• Format: Article
• Language: English
• Subjects: Astronomical models; Astrophysics and Astroparticles; Cosmology; Original Paper; Parameters; Perturbation methods; Physical properties; Physics; Physics and Astronomy; Quintessence (cosmology); Tensors
• ISSN: 0973-1458; 0974-9845
• DOI: 10.1007/s12648-022-02470-5

In the present study, the Kantowski–Sachs perfect fluid cosmological model in modified theory suggested by Harko et al. [1] is obtained. In this paper, the functional form f ( R , T ) = f 1 ( R ) + f 2 ( T ) = R + α R 2 + λ T of f ( R ,  T ) gravity where α and λ are constants, R is Ricci scalar, and T is the trace of energy–momentum tensor is considered. To get the solutions to the field equations, the following two conditions are used: (i) hybrid expansion law of the scale factor and (ii) expansion scalar is proportional to the shear scalar. We have computed dynamical and physical parameters, and their relevance to modern cosmology is also explained with the help of their plots. For various values of α 1 and a fixed value of α 2 , it is noticed that the pressure is negative, whereas energy density is positive representing the accelerating universe. We have observed that NEC is satisfied for all the values of α 1 and a fixed value of α 2 , which results in the quintessence region of the EoS parameter. The stability of the solutions of the obtained model is verified using the perturbation technique. Finally, all cosmological parameters are compatible with recent observational data.