IQM says its 54-qubit Emerald chip reached full-chip GHZ entanglement at 0.516 fidelity
IQM Quantum Computers says its cloud-accessible Emerald system prepared a Greenberger–Horne–Zeilinger (GHZ) state across all 54 physical qubits at once. The company reports a fidelity of 0.516 at 54 qubits with readout error mitigation applied, and 0.515 at 40 qubits without it, both above the 0.500 threshold used to separate genuine entanglement from noise. IQM attributes the result to about a year of work on calibration, gate selection and error-reduction tools such as dynamical decoupling, plus an automated state-preparation routine that picks gates and qubit order to minimize idle time. The company says these changes cut error rates for quantum operations by up to 50%, and that cloud customers can now access the same full-chip performance.