Three measurements reveal how quantum computers disturb what they measure

Every time a quantum computer measures a qubit mid-computation, the act of measuring disturbs the qubit's state for whatever comes next — and standard error models ignore this. By running just three repeated measurements on a maximally mixed qubit, this protocol extracts the full backaction fingerprint, including asymmetric decay effects standard models miss. Tested on IBM superconducting processors, the approach improves prediction accuracy by ~100× over conventional methods, with direct payoff for quantum error correction and circuit reset operations.