Effectiveness of rastall gravity in modified chaplygin gas inspired viscous-flation

Abstract

This paper is a contribution to study the effectiveness of Rastall gravity (RG) by another mechanism of warm viscous inflation inspired by modified Chaplygin gas (MCG). The matter contents of our cosmos are taken to be standard scalar field (ϕ) and radiation within flat FRW geometry. We establish the current model using intermediate form of scale factor and calculate the analytic solution of inflaton, effective potential V(ϕ) necessary to inflate the Universe and entropy density S under slow-roll limit. The further work in this paper is restricted to high dissipative regime, taking constant and variable dissipative (Γ) and viscous coefficients (ξ). The evaluated exact solutions are the main source in developing the inflationary observable like scalar/tensor power spectra, scalar/tensor spectral indices, tensor to scalar ratio and running of scalar spectral index for our model. The model parameters as well as additional theory parameter λ are constrained to check the compatibility of RG with Planck 2018 data via and α s − n s trajectories. We conclude that RG along with modification of CG model can lead to significant changes in the early universe.