Fluxus · surrogates
Every engine, with its number
and its limits.
One page per surrogate: what it predicts and for whom, the public reference it was measured against, the held-out metric and the split behind it, the envelope it is trusted inside, when it refuses, and where a simpler baseline wins. Every reference is a simulator or a published device measurement. Nothing here is validated against fabricated hardware.
Fluxus-Q
Product overviewResonator frequency
ServedThe resonant frequency of a coplanar-waveguide readout resonator, from its layout geometry, with a fractional error band on every answer.
0.48%median error vs HFSS, claw given1.09% p95 · grouped split · n = 1,160
Full page
TransmonCross Hamiltonian
ServedThe circuit Hamiltonian of a TransmonCross qubit coupled to a readout resonator — qubit frequency f01, anharmonicity, resonator frequency, coupling g and dispersive shift χ — from layout geometry and junction inductance.
0.30%charging-energy error vs HFSSmedian · 1.67% p95 · grouped split · n = 1,934
Full page
Radiation-correlated errors
Served with caveatsFor a proposed qubit chip: how often cosmic-ray muons and environmental gammas cause correlated error bursts, how many qubits a burst covers, how much back-side phonon traps would help, and where a correlated floor starts to bind for a given code distance.
9.5/hrmuon burst rate vs Willow's measured 9.3/hronly at an assumed 0.3 mm die · 3.84× high at 0.5 mm
Full page
Frequency-collision yield
Analytic engineThe fraction of fabricated chips, under a given frequency spread, with no frequency collision — and which rules and which qubits drive the losses.
39.6%of ibm_brisbane's real gates violate rule 457 of 144 · why rule 4 is off by default
Summary
Fluxus-S
Product overviewRSFQ cell margins
ServedWhether an RSFQ library cell works at a given set of design knobs, and — only beside a functional verdict — its bias and critical-current (Ic) margin bands, each with a conformal interval.
427×faster than the JoSIM margin run8.8 ms per call vs 3.78 s · single design
Full page
RSFQ cell characterization
Analytic engineA single-cell datasheet: functional verdict, bias and Ic margins, propagation delay, maximum toggle rate, process-variation yield, and whether the fast surrogate agrees.
1call for a full single-cell datasheetmargins · timing · fmax · yield
Summary
Not offered
Routes that exist in the engine but are not served on hosted Fluxus. A call returns a refusal that says so, not a number.
- RSFQ margin optimization (/v1/fluxus/sfq/optimize) — refused in production.
- Preflight on hosted Fluxus — not offered.
- RSFQ margins for and2, or2, merger, dro and clock_splitter — these cells abstain.
Withdrawn
What we took back.
Figures we published and withdrew, ideas we killed, and a rule we switched off — each with the measurement that did it.
Withdrawn claims