Q-Day Index
RSA-2048 · launch targetA 0–100 measure of how close today's quantum hardware is to breaking RSA-2048 encryption, scored against a named, published resource estimate. Higher means closer. The honest reading today is low single digits — the trajectory is the story, not the digit.
The field's leading edge sits at 8.36 / 100, and today's real-world threat to RSA-2048 is low. The table below names every machine and its score. One system is non-zero today only because it is the sole machine with a publicly demonstrated below-threshold result — the ranking will shift as others clear that same bar. The rule, not our opinion ↗
× FidelityGate
× ECSignal × 100
Distance to the named RSA estimate. Multiplicative. Honest zeros everywhere a system lacks demonstrated error-corrected logical qubits. This is the headline and it stays uncompromising.
Progress toward the preconditions (fidelity, error-correction, scale). Additive. NOT distance to breaking RSA. A machine can have real readiness and a 0.000 threat score at once — that is the correct, honest state of the field.
Per-system
The raw 2-qubit fidelity column is deliberately not shown as a ranking. Each value carries its measurement method (XEB vs ECR vs RB vs …); these are not comparable to the third decimal. The cross-method problem, in full ↗
What would change this score
The threat score is gated on one thing above all: standing, error-corrected logical qubits, evidenced by a demonstrated below-threshold result. The readiness bars above show which preconditions each system has assembled toward that. Concretely, the frontier moves when:
The visible climb
Prior-generation systems, shown for context. The climb is real and we show it. We do not publish a projected "Q-Day year" — a forecast is only as good as its model, and ours is held back until it is defensible. Receipts, not press releases.
See a number you disagree with?
This index is only as good as the scrutiny it survives. If a spec is wrong, a source is weak, a method tag is misapplied, or a system is missing — tell us. Concrete corrections improve every subsequent run. For long-form critique or anything you want a public record of, open a GitHub Issue instead.