Published in Nature Physics on October 9, 2026, an IBM-led study reported that adaptive measurements and conditional resets can steer quantum dynamics. The researchers observed transitions between chaotic and controlled behavior, and between quantum and classical dynamics, in systems of up to 100 qubits. The paper describes the experiment and its results.
How measurement feedback steers the circuit
The experiment implemented a quantum version of the Bernoulli map, a classically chaotic system. Entangling operations scramble quantum information; local measurements taken partway through the circuit then determine conditional resets that steer the system toward a fixed point. The feedback and scrambling compete, shaping how the dynamics evolve. The study describes this protocol.
As the balance between those processes changes, the researchers report transitions between chaotic and controlled dynamics and between quantum and classical dynamics. The result is an experimental study of how measurement and feedback can shape monitored quantum behavior.
IBM Fez and the conditions behind the operation counts
The study’s supplement identifies the experimental processor as IBM Fez, a 156-qubit device. The circuits used systems of up to 100 qubits. For each system size and control probability, the team ran 50 circuit realizations and repeated each realization for 1,000 shots. Tested system sizes ranged from 10 to 100 qubits in steps of 10; the control probability, p, ranged from 0.2 to 0.85 in steps of 0.05. The supplementary information gives the device identification and experimental settings.
At L = 100 and p = 0.5, the critical setting, the circuits used about 5,000 two-qubit gates and nearly 5,000 resets. At the same system size but p = 0.2, the reported two-qubit gate count reached about 8,000. Those figures describe different operating conditions. The supplement identifies p = 0.5 as the most resource-intensive point for circuit duration, because resets take substantially longer than two-qubit gates.
What the result says about quantum computing
The researchers estimated universal critical properties and compared their results with numerical simulations. Their finding concerns the control and study of monitored quantum dynamics. A complete error-correcting code and fault-tolerant quantum computation are separate milestones; this experiment did not demonstrate either.
