Have primordial gravitational waves been detected?
Nicola Bartolo, Michele Liguori and Sabino Matarrese
Dipartimento di Fisica & Astronomia “Galileo Galilei”
& I.N.F.N. Sezione di Padova
On March 17 2014 the collaboration BICEP 2, formed by a team of
american astronomers, has announced a major discovery:
a specific polarization pattern in the Cosmic Microwave Background
radiation, which is expected to arise from a gravitational-wave background
originated by quantum effects during inflation, an epoch of accelerated
expansion taking place in the very early universe. This discovery, if
confirmed, provides the smoking gun proof of inflation, opens up a new
window on the physics of the very early universe (intriguingly, at the GUT
energy scale) and a new era for gravitational-wave based cosmology.
We will describe the scientific background of this discovery, discuss its
consequences on the physics of the early universe and for the inflationary
models, and the prospects for confirming (or
disproving) it via the forthcoming analysis of Planck polarization data.