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Inflation is known to produce large infrared scalar fluctuations. Further, if a scalar field $(\chi)$ is non-minimally coupled with gravity through $\xi \chi^2 R$, those infrared modes experience \textit{tachyonic instability} during and…
In this work we study one of the most appealing string theory-motivated models, we present a tachyonic inflationary model in the recently proposed symmetric teleparallel framework, and examine constraints on tachyon inflation with the…
Inflation elegantly provides initial conditions for the standard model of cosmology, while solving the horizon, flatness, and magnetic monopole problems. Inflationary models make predictions for the tensor-to-scalar ratio $r$ and the…
In this work we revisit $\alpha$-Starobinsky inflation, also know as $E$-model, in the light of current CMB and LSS observations. The inflaton potential in the Einstein frame for this model contains a parameter $\alpha$ in the exponential,…
Bayesian inference techniques are used to investigate situations where an additional light scalar field is present during inflation and reheating. This includes (but is not limited to) curvaton-type models. We design a numerical pipeline…
We systematically study the renormalizable three-term polynomial inflation in the supersymmetric and non-supersymmetric models. The supersymmetric inflaton potentials can be realized in supergravity theory, and only have two independent…
We study the impact of perturbative reheating on primordial observables in models of multiple-field inflation. By performing a sudden decay calculation, we derive analytic expressions for the local-type non-linearity parameter $f_{\rm…
Recent measurements from the Atacama Cosmology Telescope (ACT), combined with Planck and DESI data, suggest a higher value for the spectral index $n_s$. This places Starobinsky inflation at the edge of the $2\sigma$ constraints for a number…
A simple model of quintessential inflation with the modified exponential potential exp(-\alpha \phi) [A + (\phi-\phi_0)^2] is analyzed in the braneworld context. Considering reheating via instant preheating, it is shown that the evolution…
We construct effective supergravity theories from customized constrained superfields which provide a setup consistent both for the description of inflation and the subsequent reheating processes. These theories contain the minimum degrees…
We investigate the inflationary predictions of a simple Horndeski theory where the inflaton scalar field has a non-minimal derivative coupling (NMDC) to the Einstein tensor. The NMDC is very motivated for the construction of successful…
We consider two non-canonical scalar fields (tachyon and DBI) with E-model type of the potential. We study cosmological inflation in these models to find possible $\alpha$-attractors. We show that similar to the canonical scalar field case,…
We derive the reconstruction formulae for the inflation model with the non-minimal derivative coupling term. If reconstructing the potential from the tensor-to-scalar ratio, we could obtain the potential without using the high friction…
We study (p)reheating in modular (closed string) inflationary scenarios, with a special emphasis on Kahler moduli/Roulette models. It is usually assumed that reheating in such models occurs through perturbative decays. However, we find that…
We study the dynamics and perturbations during inflation and reheating in a multi-field model where a second scalar field $\chi$ is nonminimally coupled to the scalar curvature $(\frac12 \xi R\chi^2$). When $\xi$ is positive, the usual…
The reconstruction of a warm inflationary universe model from the scalar spectral index $n_S(N)$ and the tensor to scalar ratio $r(N)$ as a function of the number of e-folds $N$ is studied. Under a general formalism we find the effective…
The precision reached by the recent CMB measurements gives new insights into the shape of the primordial power spectra of the cosmological perturbations. In the context of inflationary cosmology, this implies that the CMB data are now…
We investigate a form of $ f(R) = {R^{1+\delta}}/{R_c^{\delta}}$ and study the viability of the model for inflation in the Jordan and the Einstein frames. This model is further analysed by using the power spectrum indices of the inflation…
Despite its importance for modeling the homogeneous hot early universe very little is experimentally known about the magnitude of the reheating temperature, leaving an uncertainty of remarkable 18 orders of magnitude. In this paper we…
In the no-scale supergravity with Type-I Seesaw model of Non-minimal supersymmetric standard model (NMSSM), we have analysed inflation, reheating and leptogenesis. A no-scale supergravity realization of Starobinsky model of inflation in…