Dark Energy

Measurements of supernovae distances first showed that the expansion rate of the Universe is accelerating. This finding is consistent with the idea that a large part of the energy of the Universe is stored into dark energy. Further evidences from surveys of distant galaxies and from gravitational lensing corroborates this interpretation. It is currently not known whether dark energy is a cosmological constant or a new, extremely light particle. I work on this second possibility, assuming that dark energy is a manifestation of a quintessence field.