All 54 qubits entangled: IQM brings full-chip performance to cloud users
Finnish quantum computer maker IQM has entangled all 54 qubits of its Emerald processor at once. Until now, only about 30 qubits could be used reliably within a single algorithm.
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IQM Quantum Computers, based in Espoo, Finland, said it created a so-called GHZ state across all 54 qubits of its cloud-accessible Emerald processor. In this Greenberger-Horne-Zeilinger state, every qubit on the chip is entangled with the others at the same time. The company measured a fidelity of 0.516 across all 54 qubits with readout error mitigation and 0.515 at 40 qubits without it. Both values exceed the 0.5 threshold that separates genuine entanglement from noise.
Until now, users could reliably use only about 30 qubits within a single algorithm on Emerald, according to IQM. The company credits a year of calibration and hardware work, an improved gate set and an automated routine that selects qubits and gate order to keep idle time to a minimum. It said error rates for quantum operations fell by up to 50% as a result. “Entangling the entire chip means every qubit and every connection between them has to work correctly in the same circuit,” Chief Technology Officer Craig Ciesla said.
IQM said the same full-chip performance is now available to its cloud customers. Founded in 2018, the company builds superconducting quantum computers, employs more than 450 people and has major operations in Munich. IQM is listed on the Nasdaq and describes itself as the first European quantum company to list there. Besides cloud access, it also sells systems that customers operate on their own premises.