Quantum engineers from UNSW Sydney have solved a problem that has baffled scientists for decades: How to reliably control millions of qubits in a silicon quantum computer chip without wasting valuable space with extra wiring.
This issue had been a significant roadblock to the development of a full-scale quantum computer, but it has now been overcome thanks to the engineers who developed a new technique capable of controlling millions of spin qubits simultaneously.
"Up until this point, controlling electron spin qubits relied on us delivering microwave magnetic fields by putting a current through a wire right beside the qubit," team leader Dr. Jarryd Pla said, a faculty member in UNSW's School of Electrical Engineering and Telecommunications, in a press release by the university.
"First off, the magnetic fields drop off really quickly with distance, so we can only control those qubits closest to the wire. That means we would need to add more and more wires as we brought in more and more qubits, which would take up a lot of real estate on the chip," Pla explained.
Furthermore, because the chip must operate at freezing cold temperatures, adding more wires would generate far too much heat in the chip, compromising the qubits' reliability.
The team claims to have found "the missing jigsaw piece" in the quantum computer architecture in a paper published in Science Advances, which should enable them to manage the millions of qubits needed for extremely complicated computations.
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