get_logical_noise:
The models
Λ is the error-suppression factor per two units of code distance — how much the logical
error rate improves each time you grow the code. Larger is better, and Λ ≤ 1 means the
code no longer suppresses errors at all.
The two device-flavored models are illustrative reference points, not vendor calibration
snapshots. They are rounded from published figures to give you a feel for how real
superconducting hardware behaves; they are not tracked against any vendor’s live
calibration data, and no vendor publishes every parameter the engine needs.
Physical parameters
See Custom Noise Models for what each field
means and which rules it accepts.
public/depolarize_1e-3
A general-purpose depolarizing model, generated from custom_noise_model(1e-3) as defined
in Custom Noise Models. Use it as a
well-behaved baseline rather than as a model of any particular machine.
public/google_willow_like
Flavored after a superconducting processor tuned for error correction: fast surface-code
cycle, comparatively short coherence, and a dedicated multi-level reset with leakage
removal — so its reset error is well below its readout error.
T1 of 68 µs against the gate and cycle durations; reset is an assumption.
public/ibm_heron_r2_like
Flavored after a superconducting processor with roughly three times the coherence but
slower, measurement-limited readout and reset.
T1 on the order of 200 µs against the gate and readout durations; reset is assumed
to be measurement-limited.
References
The device-flavored models are rounded from the public sources below. All of them are point-in-time figures — vendors recalibrate continuously, and these models are not tracked against live calibration data.- Willow Spec Sheet
(Google Quantum AI, 9 December 2024) — single-qubit, CZ and measurement error under
simultaneous operation, mean
T1, surface-code cycle time, reset capabilities, and the measuredΛ₃,₅,₇ = 2.14 ± 0.02for the error-correction chip. - Quantum error correction below the surface code threshold
(Google Quantum AI, Nature, 2024; arXiv:2408.13687) — gate and cycle durations,
coherence, and the surface-code memory experiment that
Λis measured from. - IBM Quantum compute resources — per-device
calibration for the Heron r2 systems (
ibm_fez,ibm_kingston,ibm_marrakesh), including both best-pair and layered two-qubit error and median readout error. - IBM Quantum Computers: Evolution, Performance, and Future Directions (arXiv:2410.00916) — Heron r2 CZ gate duration and median CZ error.
- Parameter Analysis and Optimization of Layer Fidelity for Quantum Processor Benchmarking at Scale (arXiv:2510.16915) — layer fidelity and error per layered gate for Heron r2, the basis for modeling the two-qubit error with a layered rather than an isolated figure.