A UCFT No-Tachyon Criterion for the Riemann Hypothesis

We formulate a conditional UCFT criterion for the Riemann Hypothesis. The criterion is based on a single spectral-arithmetic axiom: the physical zeta sector of arithmetic-completed UCFT is the norm-channel quantization of the integral Albert--EIII charge lattice, and its shifted physical zeta determinant is the regularized determinant of a positive self-adjoint mass-squared operator. From this axiom we derive the finite prime-orbit trace, the completed physical zeta factor, and the critical-line condition. The Riemann Hypothesis is thereby reformulated as the no-tachyon condition for the physical UCFT zeta sector.