After a short discussion of the central tenets at the basis of inflation, a review of how the most recent Cosmic Microwave Background (CMB) anisotropy measurements constrain this theory is presented.
However, cosmic inflation is not only a successful paradigm to understand the early Universe. It is also the only situation in Physics where one crucially needs General Relativity and Quantum Mechanics to derive the predictions of a theory and, where, at the same time, we have high-accuracy data to test these predictions.
Indeed, according to inflation, the large scale structures observed in our Universe (galaxies, clusters of galaxies, Cosmic Microwave Background - CMB - anisotropy . . . ) are of quantum mechanical origin: they are nothing but vacuum fluctuations, stretched to cosmological scales by the cosmic expansion and amplified by gravitational instability.
This means that inflation is also a playground to investigate foundational issues and some aspects of these questions will be discussed.
