BURIDAN: the ambiguous picture, decided by a 144-qubit collective with its controller in the loop. A registered experiment

On the IBM Heron processor ibm_fez, 144 qubits form 36 domains of four. A field law running on a microcontroller (an ESP32-S3, firmware v4.12) turns the measured populations of every cycle into the rotation angles of the next, and a Hebbian coupling matrix of two images, a unicorn and a heart, makes the two images attractors of the collective: cued with part of either, the field completes it. The experiment writes a blend of the two: of the 16 pixels on which the images differ, k are taken from the unicorn and the rest from the heart (which pixels: fixed in the registration, per trial), the 20 shared pixels as they are. The blend is held for two cycles and released, and the field runs six free cycles on its own. Resolution is the first free cycle in which the field's majority picture agrees with one image on at least 90 percent of the pixels. Lines, thresholds and rules were fixed and hashed before the first registered job (registration SHA-256 81398e6660c6538ebcf1566b3a2ebb6ecbaaefe29da074894848516b5749acda; a first registration was refused by its own budget guard after four burn jobs and is part of the deposit). Results, as they fell: of 13 field-on trials 11 resolved into one of the two images; the fraction resolved to the unicorn was 0.00, 0.00, 0.33, 0.50, 1.00, 1.00 for k = 5, 7, 8, 9, 11, 13, a monotone curve with a single flip whose interpolated crossing lies at k* = 9.0; the censored decision time was 4.4 cycles at the two levels nearest the flip against 1.0 at the levels far from it; the two field-off controls, the same blend with the inter-domain coupling off, never resolved. The device's lean, read from the cycles in which the field was off, pointed to the heart and moved the fair point up by about one pixel, as the registered exploratory line asked. All five binding lines and the exploratory line held. The decision dynamics is the one a textbook predicts, a mean-field quench of 16 domains from the blend's magnetisation; the content of the experiment is that it runs, pre-registered to the pixel, on a quantum collective with the controller in the loop. Two chips were in the loop: the controller (ESP32-S3, with the field, the coupling matrix and the agents drawn on its display during the run) and a witness (ESP32-C3) running the byte-identical kernel source, compiled with the same arctangent and without fused multiply-add, so that the RISC-V chip in software arithmetic and the Xtensa chip with its floating-point unit produce the same bits: a seeded programme of 527 exchanges over every kernel path gave the same vector on both before the run, and on every one of the 148 ticks of the run the witness returned the same bytes as the controller. 148 jobs of 2048 shots, one device, one night. The deposit holds the registration (and the refused first registration with its burn log), the model and registration script, the runner, the verdict script, the kernel replica, the rehearsal on the noiseless simulator with both chips in the loop under the hashed registration, the run log with the measured populations of every qubit in every cycle and the witness flag of every tick, the job ids, the verdict (formed once), the bit-check vectors of the two chips, the write-up (buridan_paper_v1.pdf) and the scripts and figures that build it. The firmware sources and binaries are not deposited; their SHA-256 are in the registration.