Executive Summary : | The early Universe dynamics can be described by two compelling inflationary scenarios: Cold Inflation (CI) and Warm Inflation (WI). During CI, the couplings of the inflaton field with other fields are generally ignored, while in WI, these couplings are assumed to be strong enough not to be ignored. This leads to dissipation of the inflaton field in a constant radiation bath during inflation, causing WI to transition into a radiation-dominated Universe when inflation ends. However, CI has been explored more in the literature than WI due to its more intricate and rich inflationary dynamics. To compare CI and WI, it is essential to explore all aspects of inflationary dynamics in both scenarios. This project aims to explore WI in areas where CI has already been explored in the literature, such as generating E-mode polarization of cosmic microwave background radiation (CMBR), causing mu-type distortions in the blackbody spectrum of CMBR, non-minimal coupling of the inflaton field with gravity, generation of primordial blackholes, and primordial magnetogenesis during inflation.
To become a viable model of the early Universe, WI should generate the E-mode polarization of the CMBR accurately, accommodate non-minimal coupling of the inflaton field with gravity, and seed magnetic fields. As CI can yield E-mode polarizations, accommodate non-minimal coupling to gravity in its dynamics, and seed magnetic fields, it is already preferred over WI as a viable model. Therefore, exploring WI further is crucial to unravel the true nature of the early Universe. |