Why is the observable universe made of matter and not antimatter, when the two are produced in equal amounts and annihilate to radiation? Sixty years after Sakharov framed the problem, no mechanism derives the measured baryon-to-photon ratio η ≡nB/nγ ≈6 ×10−10 from first principles: grand-unified and standard electroweak baryogenesis are excluded or fine-tuned, and leptogenesis is viable only with free high-scale parameters. We present a derivation of the magnitude of η from a single, parameter-free assumption: that the early universe is a finite quantum error-correcting (QEC) code, the self-dual 8,4,4 extended Hamming code, whose boot-time pruning is the physical origin of the photon bath. In this picture the asymmetry is not a fine-tuned initial excess but an error rate: almost all matter and antimatter are erased back into photons, and the surviving baryon number is the residue of logical faults that bypass the code’s stabilizers undetected. The minimum-weight undetectable fault has weight equal to the code distance d= 4, giving a suppression α4 0; a colour-singlet selection over the 14 weight-4 logical channels contributes a branching 3/14; against the Planck value 6.12(4) ×10−10 — a 0.9σ match with no free parameters once the fine- structure constant α0 is fixed. The three Sakharov conditions map onto three intrinsic features of the substrate. We are explicit about scope: the magnitude is a genuine parameter-free prediction; the lepton-number-to-baryon conversion reproduces the standard sphaleron factor 28/79 on the substrate’s particle content; and the absolute sign of the asymmetry remains, as in all of physics, anchored in a discrete convention — here a geometric phase of the code — rather than a fully derived dynamical quantity. All numerical claims are reproduced by self-asserting scripts. 2026-06-20 canon refresh: Locally updated to R14 billing/record-content and R15 CP-holonomy status; built cleanly; not yet Zenodo-synced. 2026-06-21 canon refresh: This version incorporates the 2026-06-21 ANCHOR/DRIFT/PTMS canon refresh and rebuilt local PDF. 2026-06-25 canon refresh: Zenodo-synced on 2026-06-20: new-version published as 10.5281/zenodo.20776750 (concept 10.5281/zenodo.20723972); local build/render previously checked. 2026-06-21 canon refresh applied where needed; PDF rebuilt and checked. Zenodo-synced on 2026-06-21: new-version published as 10.5281/zenodo.20786073 (concept 10.5281/zenodo.20723972). 2026-06-30 canon refresh: This version incorporates the current R1/Hasse-edge recovery, CP-holonomy, and SU(3) scale-setting status updates where relevant, with the local PDF rebuilt from source.
David Elliman (Tue,) studied this question.