The edge

This is the curve everything else is built on. Ratio over depth on a real machine, both arms: the vendor's default path and ROX. Each point is a sealed run with a job ID; the bar is one standard error.

Reading it

The dashed line is the coin flip, 0.500: the ratio a random bitstring returns. The edge is the first depth at which the default arm lands within two standard errors of that line. From there on, the default returns noise. Where the ROX arm still sits above the line, the machine still carries the structure — that is the signal ROX OS sells.

Where ROX loses, the same graph says so: Below the edge, defaults hold. We say so. Under the edge the vendor path is often as good or better; the forecast tells you that before you pay.

What moves the edge

• The machine's calibration today: worse two-qubit error, earlier edge.
• The loop ROX chose: avoiding one bad coupler can double the usable depth.
• The shots: more shots, tighter bars, the same edge.

Data: the newest measured ladder on the last measured machine, straight from the ledger. Every point links its record.