In monitored quantum circuits, measurements can trigger phase transitions, but seeing them means conditioning on the measurement record, which real readout errors corrupt. Murtaza Ali Mir, Teemu Ojanen and Ali Moghaddam of QMAT's Theory of Quantum Matter group at Tampere University have studied how such errors affect circuits that conserve charge.

They find that the charge-sharpening transition survives at a finite error rate, and that charge fluctuations show a shallow minimum near the ideal transition point, which still marks it in noisy data. Separating the quantum and classical parts of these fluctuations offers a minimal error-mitigation framework and a way to locate the transition directly from experiments. Mid-circuit measurements prove much harder to protect against readout errors than end-of-circuit ones.

The preprint has not yet been peer reviewed.

Figure: Mir et al., arXiv:2610.20712 (2026)