Inflationary Parameters and Swampland Conjectures in Various Scenarios of Gravity

Abstract

The purpose of this thesis is to investigate the inflationary parameters and swampland conjectures in the presence of scalar field and Chaplygin gas models. We investigate the inflationary parameters such as slow roll parameters, scalar power spectrum, tensor power spectrum, spectral in- dex, tensor-to-scalar ratio in the presence of scalar field and Chaplygin gas models and also discuss the recently proposed swampland conjectures. The inflationary scenario is assumed to be working under a standard scalar field having Γ as decay ratio. This decay ratio has dependence in the form of generic power-law of scalar field φ along with thermal bath temperature T , that is, Γ(φ, T ) = Cφ T a φa−1 , where Cφ is dimensionless parameter and a is inflation decay rate. Assuming that our model bends according to strong dissipative regime (R À 1), we study the background and perturbative dy- namics as well as inflationary observable as the scalar power spectrum PR, scalar spectral index ns, dissipative ratio R, the tensor-to-scalar ratio r, run- ning of the scalar spectral index dns d ln k and generalized ratio of Swampland de-Sitter conjecture T´V V´ T for three different potentials V (φ) = 3H2 inf 8π e 2φ p(φ+1) , V = M4 µ φ Mp ¶ 2 µ 1 + β φ2 M2 p ¶ and V = 3 4 M2(1 − e √ 2 3 φ)2 respectively.