Decoupling the Bounce from the Spectrum: Generation at Low Density in Einstein-Cartan Cosmology

The Einstein-Cartan bounce at the Aldred Limit, rho_A = 9.72e54 g/cm^3, is a statement about a background of fermion dust. That background contains no sector that generates primordial perturbations, and the companion spectrum calculation (corrected version, DOI 10.5281/zenodo.24113975) shows that its bound rho_b <= 2.77e54 g/cm^3 is a property of a conjunction - generation at the bounce density, a single-component identification, and unit transfer across the bounce - not a bound the background supplies alone. This paper settles the standing of the spectral index for this cosmology by formal decoupling: primordial perturbations are adopted to be generated at x* << 1, where x* = rho*/rho_A is the density at generation in units of the Limit, in a sector separate from the bounce, and the bounce is therefore not constrained by the measured spectral index. Under the adoption the bounce's residual imprint on the tilt is Delta n_s = -4 eps_V x*^2/((1-x*)(1-2x*)) ~ -4 eps_V x*^2: at the benchmark eps_V = 0.004 it is -1.65e-06 at x* = 1e-2 and -1.60e-08 at x* = 1e-3, respectively about 2.5e3 and 2.6e5 times below the Planck uncertainty (n_s = 0.9649 +/- 0.0042). The costs are stated at full size: the cosmic microwave background spectrum carries no information about the bounce under decoupling; the bounce model's observational contact through the spectrum is surrendered until a generation mechanism native to it is computed; and the generation sector itself remains unspecified. The two candidates are named and scoped, not computed: matter-bounce generation on the contracting dust branch (pure dust gives n_s = 1 exactly; the observed tilt requires a specified w(t); mode mixing through the H = 0 layer is uncomputed) and a postulated slow-roll sector (a scalar field the bounce model does not contain, whose density must be carried in two-component bookkeeping with the fermion fraction at generation below about 2.67e-03). All numbers are reproduced by the deposited compute.py. AI-use disclosure: the derivation and computation were prepared with the assistance of Dave, an artificial intelligence system operated by Aldred Industries; the author takes responsibility for the results.