A fundamental question in cosmology is whether dark energy evolves over time,
a topic that has gained prominence since the discovery of cosmic acceleration.
Recently, the DESI collaboration has reported increasing evidence for evolving
dark energy using combinations of cosmic microwave background (CMB), type Ia
supernova (SN), and their new measurements of baryon acoustic oscillations
(BAO). Tuttavia, our analysis reveals that these combinations are problematic
due to clear tensions among the CMB, BAO and SN datasets. Consequently, DESI’s
claim of dynamical dark energy (DDE) is not robust. A more reliable approach
involves constraining the evolution of dark energy using each dataset
independently. Through a statistical comparison for each dataset, on average,
we find that DDE is strongly preferred over the $\Lambda$CDM model. This
suggests that DDE likely exists, although its real parameter space remains
elusive due to weak constraints on the dark energy equation of state and
inconsistencies among the datasets. Interestingly, when considering DDE, none
of the individual datasets — including CMB, DESI DR2, Pantheon+, Union3, E
DESY5 — can independently detect cosmic acceleration at a significant level.
Our findings not only clarify the current understanding of the nature of dark
energy but also challenge the established discovery of cosmic acceleration and
the long-held notion that dark energy exerts negative pressure. Both individual
and combined datasets suggest that the ultimate fate of the universe is likely
to be dominated by matter rather than dark energy.

Questo articolo esplora i giri e le loro implicazioni.

Scarica PDF: