Reciprocal Cosmology I: Late-time Ultralight Axion Dynamics as a Unified Explanation for Large-scale CMB Anomalies

This paper proposes that the dynamical thawing of an ultralight axion fieldϕ(x, t) in the late universe can explain multiple large-scale CMB anomalies—low-ℓpower suppression, hemispherical asymmetry, and TB/EB cross-spectra—from asingle origin. Long-wavelength modes of post-inflationary relic axions and horizonscalelocal energy concentration structures (eDAS; excess Directional AsymmetricStructure, also referred to as pseudo-topological energy-dense asymmetric structures)are amplified as Hubble damping weakens, inducing late ISW contributionsand direction-dependent cosmic birefringence. The photon-axion coupling gϕγ generatesa spatially anisotropic polarization rotation β(ˆn), producing TB and EBcross-spectra.v3.1 Final refinements: (1) Complete mathematical definition ofeDAS with all variables explicitly explained; (2) Enhanced figure captions with detailedphysical interpretation; (3) Added timescale context to Table 1; (4) Acknowledgmentsinclude AI collaboration; (5) Final formatting optimized for arXiv submission.Keywords: CMB anomalies, ultralight axion, cosmic birefringence, ISWeffect, eDAS, parametric resonance, TB/EB cross-spectra, LiteBIRD