open-standards/wai/quantum-conformance/qec-text/README.md

qec-text

The error-correction text formats, as the engine reads and writes them: noisy Clifford circuits with detectors and observables (circuits/), and detector error models (models/). The reader and writer are wai_quantum::quantum_qec_text; the circuits' meaning, sampling and models are wai_quantum::quantum_frame.

Every file here is in the writer's layout (NAME[tag](a, b) t1 t2, a block's body four spaces in), so each must come back from reading and writing byte for byte. vectors.json pins, for each:

field	what
qubits, measurements, detectors, observables	the circuit's counts after its blocks are unrolled
tags	the tags its instructions carry, each once, in order
text_blake3	BLAKE3 of the file
model, model_blake3, mechanisms	the file holding the circuit's detector error model, as the engine writes it (coordinates, tags, decompositions), and its hash and size
generator	for a circuit the crate writes, the call that writes it: the file must be what the code writes today
reference	one noiseless run of the circuit, every random result reading 0: how many results are random, and record_blake3, BLAKE3 of the record as 8-byte little-endian words of 64 measurements
samples	at shots shots of seed: detections_blake3 and measurements_blake3, the digests of the detection events and of the measurement records. The algorithm and the digests are fixed in extensions/quantum-sim.md §10, so a second implementation can produce them

A model's vector gives its detectors, observables and mechanisms after its repeat blocks are unrolled and shift_detectors applied, how many are decomposed (parts joined by ^) and how many tagged.

The files:

• surface_z_d3_r3, surface_z_d5_r1: the rotated surface-code memory experiment, Z basis, every noise knob at p.
• bb72_z_c2, bb72_x_c1: the [[72,12,6]] bivariate-bicycle memory, its depth-8 syndrome cycle, in each basis.
• cultivate_d3_k2, cultivate_d5_k2: the Clifford form of a magic-state cultivation circuit in the triangular colour code (quantum_cultivate: every T an S), noise at 0.001, a detector on every measurement. The circuits themselves, T gates and all, are cultivation/*.qasm; the cultivation list pins each one's counts, the order its checks meet the data qubits in, its text's BLAKE3 and unseen_faults: the fewest faults of the Clifford form that fire no detector and flip the observable, searched to four.
• tagged: written by hand. Tags on a gate, on noise and on a REPEAT; Pauli-target observables (OBSERVABLE_INCLUDE(1) X0 X1 X2 on a three-qubit cat state, OBSERVABLE_INCLUDE(0) rec[-1] Z2 beside a measurement record); an inverted measurement target (M !0 1); coordinates shifted by SHIFT_COORDS. A tag on a noise instruction is the tag of every mechanism it makes, and mechanisms with one symptom set but different tags stay apart.
• correlated: written by hand. C_XYZ and C_ZYX on a qubit that a detector reads through them; E and CORRELATED_ERROR on Pauli targets, so the circuit holds one qubit more than its text names; PAULI_CHANNEL_1, as the independent flips with its law, one rate above 1/2.
• refuse/no_independent_flips.circuit: PAULI_CHANNEL_1(0.1, 0.1, 0), which no independent flips give.
• models/decomposed.dem: written by hand. Decomposed errors, a tagged one, a repeat block with shift_detectors, detector coordinates and a declared observable no error flips.

refuse/ holds text the engine must refuse, each with its line and the words of its refusal in vectors.json: an instruction it does not implement (T, and a Pauli product measurement it reads but does not run), an observable that is random without noise, a record before the first measurement, a tag left open, an empty part of a decomposed error, and an unknown model instruction.

The test is wai/wai-quantum/tests/qec_text_conformance.rs:

cargo test --release --features full --test qec_text_conformance
WAI_QUANTUM_BLESS=1 cargo test --release --features full --test qec_text_conformance   # rewrite the generated files