Non-Local Cosmological Observables in MRUV Cosmology: A Unified Framework for H0 Estimator Drift and Cosmic Birefringence

Cosmological observables are commonly interpreted as direct probes of underlying dynamical quantities. However, a series of recent results in MRUV cosmology has shown that key observables — such as the Hubble parameter inferred from finite redshift windows and the rotation of CMB polarisation — exhibit systematic deviations that cannot be fully understood within a purely local interpretation. In this work we provide a unified operator-based framework that consolidates these results by expressing cosmological observables in the form O = Π∘GX, where G represents propagation through spacetime and Π denotes observational projection. Within this formulation, observables defined over finite propagation intervals are intrinsically non-local and do not coincide with the underlying dynamical quantities. We show that the H0 estimator drift and cosmic birefringence of the CMB (β = 0.30° ±0.11°, Diego-Palazuelos et al. 2022) are different manifestations of the same non-local operator structure. Birefringence is identified as the polarimetric realisation of the Mirage Operator introduced in earlier work (Prevedello 2026c), with rotation angle Δα = ε Φt0/c. The coupling parameter ε is interpreted as a structurally constrained quantity whose order of magnitude is fixed by the near-apex geometry of the MRUV universe: 1−Φt0/c ≈ 2.30×10⁻³, where Φ ≈ 5.571×10⁻¹⁰ m s⁻² is the universal deceleration field, t0 = 17.024 Gyr is the cosmic age, and tmax = c/Φ = 17.0634 Gyr is the maximum-expansion epoch. The observed value εobs ≈ 5.3×10⁻³ is consistent with this geometric scale up to an order-unity projection factor. This unified perspective does not introduce new dynamical components, but reinterprets existing anomalies as consequences of non-local propagation and inference. The framework leads to testable predictions linking birefringence, redshift dependence, and estimator drift, and suggests that part of the current cosmological tensions may arise from the intrinsic non-local nature of observational processes. Cosmological observations may not reveal new components of the universe, but the non-local nature of how we observe it.