Readable Quantum Dynamics Without Error Mitigation: Dual-Unitary Chains up to 91 Qubits and 3D Lattice Tests on IBM Heron Devices

Paper 7 of this series carried user-written two-dimensional circuits through an operating layer (psf-os) that reads no calibration-quality number, adds its own controls to each job and applies no error mitigation. Here the same policy is carried to a chain that no fixed shape can hold and to three-dimensional lattices that the heavy-hex coupling graph cannot embed. IBM's dual-unitary kicked-Ising chain (arXiv:2411.00765) at its largest width, N = 91, read raw on ibm_marrakesh: the decay rates agree with cos 2h at all three h (largest |k - cos 2h| 0.0037) and every depth up to t = 24 (2 205 CZ) is readable, on a chain placed by a fixed rule round the failed elements; a second run on ibm_fez, with the ruler h = 0 in both jobs, again found all three rates in agreement, while h = 0.15 sat +0.0037 above cos 2h on both devices. In three dimensions, a place rule that judges the place with the highest own mirror replaced a gate that had refused every place at 48 and 72 sites; kicked Ising on 4 x 4 x 3 read at every angle and depth, Heisenberg XXX on 4 x 2 x 2 read with a Neel retention of 0.72 to 0.51. Two new layouts cut the transport CZ of the Heisenberg step by 42%, and were compared with the old one on the same places of two devices; an Ising layout with 46% fewer CZ came closer to the exact answer at the judged 4 x 2 x 2 place but farther on 4 x 3 x 2. On the way we changed our main measure for such comparisons, from the retention of an order parameter to a normalised per-site error, because noise that slows the dynamics can raise the retention. Pair creation in the Schwinger model read in 16 of 18 circuits and beat both trivial guesses in all 18. A light-cone test failed as predicted: every front arrived late, while the shape of the spread was reproduced. Every device result re-scores to the same numbers from its committed raw counts (23 of 23). No quantum advantage is claimed: every answer is computed exactly on a classical machine.