The discovery of cosmic acceleration established dark energy as one of
the central problems in cosmology. In the standard cosmological model,
dark energy is described by a cosmological constant, yet its extremely
small value remains difficult to reconcile with expectations from
quantum field theory. Recent DESI results, combined with other
cosmological probes, suggest that dark energy may evolve with cosmic
time. In this talk, I will first review the observational evidence for
dark energy, what current data tell us about its properties, and why
evolving dark energy is theoretically challenging. I will then discuss
the possibility that dark energy may not require a new particle or
field, but could instead emerge from known but overlooked physics within
the Standard Model of particle physics.
Description