Speaker
James Cline
(McGill University, (CA))
Description
The Dark Energy Spectrometer Instrument second data release has
strengthened indications of evolving dark energy, possibly including
the violation of the null energy condition $\rho > -p$. It is suggested that
the dark energy equation of state evolved from $w < -1$ to $w > -1$,
known as crossing the phantom divide. I will discuss
challenges to constructing theoretical models realizing this scenario,
focusing on ``ghost condensation,'' in which higher-derivative terms
in the action play an essential role. We find that the simplest such
theory can provide a reasonable fit to the $w(z)$ evolution that best
fits the DESI + CMB + Union3 data sets.
Author
James Cline
(McGill University, (CA))
