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The Aldred Limit pins a number: in the Einstein–Cartan spin-fluid model, under the incoherent prescription with coefficient 1/8, for neutron matter, the effective density turns over and vanishes at ρ_A = 9.7×10⁵⁴ g/cm³ (paper of record, deposit DOI 10.5281/zenodo.23850767). This paper asks the laboratory's question about that number — what would it cost, in density, energy and scale, to reach it on a bench — and prints the answer as its result: a negative, priced. On my bench, with every comparison value declared, ρ_A stands 51.99 dex above the peak densities of inertial-confinement fuel (order 10³ g/cm³), 52.99 dex above static diamond-anvil compression (order 10² g/cm³), 53.63 dex above the densest stable element, osmium at 22.59 g/cm³ — and 39.99 dex above even a neutron star's centre (order 10¹⁵ g/cm³), which no laboratory is. The energy face: ε = ρ_Ac² = 8.717925e+68 J/cm³, a radiation-equivalent temperature of 3.276355e+22 K, one cubic centimetre at ρ_A carrying 4.877e+21 solar masses, and a (10 micron)³ cell at ρ_A still massing 9.700e+45 g. The density's own scale: n_A = 5.791295e+78 neutrons per cm³, a mean spacing of 5.569e-29 m — the same spacing whose smallness against the neutron Compton wavelength fences the model itself, in its own paper, as a formal extrapolation. Between ρ_A and the Planck density the bench counts 38.73 dex the other way, so the bounce sits in a desert with laboratory physics fifty-two orders of magnitude below it and quantum gravity thirty-nine above, reachable by neither. Nothing in this paper weakens the bound, which is a statement inside a stated model and stands exactly where its paper puts it; what the paper prices is the bound's *testability at bench scale*, and the price is the finding: no laboratory route prices within reach, by roughly fifty-two orders of magnitude, and any claimed bench test of ρ_A should be read against this arithmetic first. Grade, printed at full size: NEGATIVE PRICED / UNREACHABILITY SHOWN ON DECLARED INPUTS — a pricing of reach, not a re-grade of the bound. The program headline stands unmoved: vacuum catastrophe NOT SOLVED / PARTIAL, producing-count 0.
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William Alexander Aldred (2026) studied this question.
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