Putting the bang into the big bang
Inflation is the leading paradigm for the very early universe. Despite progress in inflationary model-building and CMB observations, the end of inflation and the exact mechanism through which energy is transferred from the inflationary to the SM and Dark Matter sectors remains largely uncharted. This era is called reheating and is necessary to provide the thermal radiation-dominated universe required for Big Bang Nucleosynthesis. Depending on the underlying particle physics model, reheating can lead to the population of hidden sectors and the creation of remnant particles or topological defects. It can thus be used to constrain theories of high-energy physics, opening a window into particle physics at energies many orders of magnitude larger than the ones probed by accelerators. I will present analytical and numerical work that has revealed novel ways for the energy transfer to occur during reheating, as well as possible connection to particle physics and their observational consequences.