The σ8 tension remains unresolved in 2025, with CMB vs. lensing data differing by ~2-3σ. Tachyon fields show promise for DE/DM unification via negative pressure, but they struggle to lower σ8 enough without tweaking geometry. Here is a Consistent Tachyon + Λ + Background‑Safe μ(a) Pipeline - It resolves the σ₈ tension while keeping geometry intact, which ΛCDM+ν or early DE do not do as cleanly.
If it wasn’t for KATRIN I think it would still be a tenable position that the neutrino was a tachyon but it seems to have ruled out mass squared < 0. Too bad.