Sydney team runs multi-qubit logical operations on IBM's 120-qubit ibm_phoenix
University of Sydney researchers report fault-tolerant logic experiments on IBM Quantum's cloud-deployed ibm_phoenix, a 120-qubit (physical) superconducting processor based on the square-lattice Nighthawk r2 architecture. The work, in an arXiv preprint (arXiv:2610.32347) that is not yet peer reviewed, covers distance-3 and distance-5 rotated surface code memories, logical Bell-state preparation via lattice surgery, and state and gate teleportation across three logical qubits. Reported figures include memory error per round below 1%, Bell-state fidelity above 93%, teleportation process fidelity of 78% to 93%, and an error probability of about 2 x 10^-7 out to 170 rounds (8 failures in 50 million runs). The team used a dynamic 'walking' syndrome circuit that alternates data and ancilla roles each round, so every physical qubit is measured and reset every two rounds to clear leakage into non-computational states. The experiments came 54 days after the processor's fleet integration.