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We explore the swampland conjectures of quintessence and tachyon scalar field models in f (T) and Einstein gravities, respectively. In f (T) gravity, we consider cold and warm (by assuming generalized dissipative coefficient) inflationary scenarios and develop constraints on de-Sitter conjectures through Bekenstein entropy relation. In usual inflation, the de-Sitter conjecture constraint becomes constant (in terms of models constant parameters) which can be easily analyzed for its validity (i.e., | V ′ | V ≤ O (1)). However, in warm inflation, we analyze the de-Sitter conjecture constraint through τ ′ V τ V ′ , i.e., if τ ′ V τ V ′ < 1 then | V ′ | V ≤ O (1) and hence we can obtain the required result. For evaluating this condition, we choose three well-known potentials such as monomial chaotic, hilltop and generalized exponential. It is observed that the condition τ ′ V τ V ′ < 1 satisfied for all three potentials in both regimes of dissipative coefficient for specific choice of constants. We also obtain satisfactory results of de-Sitter conjecture for tachyon and polytropic (with quintessence scalar field) in general relativity. We investigate the consistency of assumed potentials through inflationary parameters n s and r comparing with Planck's observational data 2018 and found them compatible with the recent observations. [ABSTRACT FROM AUTHOR]

In this paper, we study the inflationary scenario in the realm of k-essence model and swampland conjectures. Taking into account three models of Chaplygin gas, such as generalized, modified, and generalized cosmic Chaplygin gas models, we discuss the equation of state (EoS) parameter ω , slow roll parameters (ϵ (ϕ) , η (ϕ)) , curvature perturbation (P s) , tensor to scalar ratio (r) , and scalar spectral index (n s) . As regards the k-essence model, the coupling function as a function of scalar field L (ϕ) is used. We investigate the swampland conjecture and then find the value of ζ (ϕ) , i.e., bound of second conjecture for these three models by unifying swampland conjecture and k-essence. We plot the EoS parameter ω , inflationary parameters plane r − n s and bound of swampland conjecture ζ (ϕ) − ϕ , which determine that the values of ω < − 1 for each model, r, are r < 0.0094 , r ≤ 0.0065 , r ≤ 0.0067 , and ranges for n s are [ 0.934 , 0.999 ] , [ 0.9 , 0.999 ] , [ 0.9 , 0.992 ] for generalized, modified, and generalized cosmic Chaplygin gas models, respectively, and compare their compatibility with the Planck data from 2018. Furthermore, we determine the bound for swampland conjecture as ζ (ϕ) ≤ 0.992 , ζ (ϕ) ≤ 0.964 , ζ (ϕ) ≤ 0.964 for generalized, modified and generalized cosmic Chaplygin gas models, respectively. [ABSTRACT FROM AUTHOR]