Cosmic inflation is a phase of accelerated expansion that occurred in the early universe, during which vacuum quantum fluctuations were amplified by gravitational instability and gave rise to density fluctuations on large scales. These fluctuations constitute the seeds of all cosmological structures, from clusters of galaxies to planets. Since inflation took place at very high energy, it allows one to learn about physics beyond what can be probed in particle accelerators.
I will review the main physical processes at play during inflation, how they can be constrained using high-precision astrophysical measurements, and what open issues they raise for fundamental physics. I will also highlight the role of quantum diffusion during inflation, and how it is connected to the formation of primordial black holes.
Sebastian Zell
