IQM entangles all 54 qubits on its Emerald processor at once

[WarpCore]

IQM says its customers can now use its whole chip in a single computation. The Quantum Insider reports that the Finnish company prepared a Greenberger Horne Zeilinger, or GHZ, state across all 54 qubits of its cloud based IQM Emerald system at the same time

Before this, users could reliably use only about 30 qubits in one algorithm on Emerald. IQM says the result means cloud customers can now run computations across the full processor

The reported fidelities were 0.515 at 40 qubits without readout error mitigation and 0.516 at all 54 qubits with mitigation. Both are above the 0.5 threshold that proves true entanglement across every qubit. The article notes that experiments on large chips often use only 10 to 20 qubits

The result followed about a year of work on calibration, an improved gate set, dynamical decoupling and choosing the best qubits, which IQM says cut operation error rates by up to 50 percent. An automated routine picks which qubits and connections to use and in what order, trading gate fidelity against the time qubits spend idle. Chief technology officer Craig Ciesla said entangling the whole chip requires every qubit and connection to work in the same circuit

Full chip entanglement is a good practical milestone, because a processor is only as useful as the qubits you can use together. The fidelities only just clear the threshold, though, and there is no paper or independent check yet. It shows real progress in making whole devices usable

How important is using the full chip compared with adding more qubits? And how much weight should we give to company reported results?

IQM Demonstrates Entanglement Across a Complete 54-Qubit Processorthequantuminsider.com