Finnish researchers unveil microwave controller that solves one of obstacles to scaling up quantum computers

(Sifted.eu) Researchers in Finland have unveiled a new type of microwave controller that solves one of the big obstacles to scaling up quantum computers to the size where they can be usable.
The controller, developed mainly by Aalto University and VTT Technical Research Centre of Finland, can work at close to absolute zero, the extremely low temperatures used in quantum computers. The tiny — less than a millimetre across — device can therefore be placed inside the same supercooled space as the quantum processor it is sending the signals to.
It eliminates the need to run huge numbers of wires into the quantum processor.
Cabling may sound like a trivial issue, but it is about to become a big bottleneck for scaling up quantum computers, says Mikko Möttönen, professor at Aalto University and VTT, who led the team.
“Each qubit currently needs three wires to carry the microwave signals in and out. It means the refrigerators cooling increasingly more qubits have to become larger to accommodate all the wires, and have to work harder because there is heat leakage from the cables,” he says. “It also adds to the cost, the cost of the wiring alone can be €1m on a quantum computer.”