Research Projects

The early history of the observable universe is based on two major pillars: cosmic inflation and big bang nucleosynthesis (BBN). However, much of the physics between these two stages remains poorly understood due to the lack of direct observational probes. To connect inflation to BBN, it is necessary to understand how the universe transitioned from a cold and dark regime dominated by scalar fields during inflation to a hot, thermalized radiation-dominated state required for nucleosynthesis. This phase of reheating is the transition from the end of inflation to radiation domination, when energy from the inflaton must be transferred to the relativistic degrees of freedom, leading to a hot, thermal, radiation-dominated universe. The phase of reheating influences the relationship between the cosmological scales today and those at the time of Hubble exit during the initial stages of inflation. The research proposal aims to connect the dynamics during reheating to seemingly disconnected cosmological observables, providing a new perspective on this era. The research plan will focus on the phase of reheating, examining the effects of reheating on the formation of primordial black holes (PBHs), probing the phase of reheating through the imprints on density perturbations of dark matter (DM) and their distribution in phase space, and constraining the dynamics of inflation and reheating through their imprints on primary and secondary gravitational waves (GWs).