Signatures of a Yielding Vacuum: Resolving the H0, S8, and Birefringence Anomalies in Disformal Gravity

We propose Disformal Dynamic Cosmological Relativity (D-DCR), an Effective Field Theory
(EFT) scalar-tensor framework designed to simultaneously address the major cosmological tensions
without invalidating the standard ΛCDM model in the early universe. In this updated version
(”Platinum Fit” V9), we transcend the purely conformal approximation by adopting a Bekenstein-
type physical metric. The dark sector is governed by a conformal coupling β = 0.4404 and a
phenomenological disformal drag parameter Ddrag ≈ 13.05, where the conformal scale is directly
derived from galactic dynamics (acrit). The framework alleviates the Hubble tension (H0) by gener-
ating an effective Phantom-type equation of state (w0 ≈ −1.15) in the late universe. Crucially, this
accelerated expansion is achieved safely without quantum instabilities, protected by a rigorous No-
Ghost condition, leading to H0 ≈ 73.13 km/s/Mpc (in agreement with SH0ES). Simultaneously, the
model resolves the S8 tension as the intense disformal drag neutralizes the fifth force on cosmological
scales, predicting a clustering of S8 ≈ 0.748. Furthermore, the yielding spacetime inherently acts as
an optically anisotropic medium, predicting a cosmic birefringence angle of ∆α ≈ 0.212◦. D-DCR
offers a unified and stable dictionary for late-universe anomalies, providing falsifiable predictions for
upcoming observations.