IQM, which is building superconducting quantum computers, announced that its IQM Emerald system has fully entangled all 54 qubits on the chip simultaneously, and is now available on the cloud.
These results, said IQM, rank among the strongest reported for any commercially available quantum computer; until now, a user running a comparable demonstration on IQM Emerald could reliably use on the order of 30 qubits within a single algorithm. IQM also claimed that studies show large quantum chips often use only a fraction of the available qubits, commonly 10 to 20, even when the hardware has many more.
“Entangling the entire chip means every qubit and every connection between them has to work correctly in the same circuit. Getting there came down to being smarter about how we prepare the state itself, choosing the gate order to keep idle time to a minimum,” said Craig Ciesla, CTO, IQM Quantum Computers. “Our current and prospective cloud customers now have the chance to benefit from the same tools and system performance that made this achievement possible.”
The demonstration used a Greenberger–Horne–Zeilinger (GHZ) state, a standard benchmark for large-scale entanglement, prepared across the entire IQM Emerald processor. The result was enabled by routine for state preparation that selects the best two-qubit gates while weighing gate fidelity against qubit idle time, choosing both the qubits and the gate order to minimize idle time as the state is built. IQM said it measured a fidelity of 0.515 at 40 qubits without readout error mitigation (REM) and 0.516 at the full 54 qubits with REM applied, both above the classical threshold of 0.500 that separates genuine entanglement from noise.
The result, said IQM, builds on roughly a year of hardware and calibration work across IQM’s technical teams, including an updated calibration methodology, an improved gate set and continued deployment of error-reduction tools such as dynamical decoupling. These improvements, claimed IQM, led to an error rate reduction of up to 50% for quantum operations in the processor.
