Investigations into an unobserved photonic law of nature: Quantitative Observational Bounds from the CMB: Constraining Torsional Anomaly Inflow (Paper V)

Following the mathematical and geometric architecture established in the preceding papers
of the Topological Emergence program, we extract parametric phenomenological bounds
from astrophysical data. Assuming that the four-dimensional classical vacuum is a topolog
ically protected boundary state of a Riemann-Cartan bulk, the resulting torsional anomaly
inflow predicts parity-violating macroscopic signatures. The most distinct of these is topolog
ical vacuum birefringence—an effective rotation of the polarization plane of photons travers
ing the cosmos. In this manuscript, we compare our theoretical framework directly against
recent precision constraints from the Cosmic Microwave Background (CMB). By utilizing
the latest isotropic birefringence angles from the Planck NPIPE data release and multipole
dependent constraints from the BICEP/Keck (BK18) dataset, we derive a parametric upper
limit on the strength of the topological current Jtop. Consequently, we derive a phenomeno
logical lower bound within the proposed effective framework on the string compactification
scale Λ required to sustain the holographic boundary equilibrium