Spin-Control Technique Could Lead to Billion-Qubit Quantum Chips

Scientists at UNSW Sydney and the start-up company Diraq have discovered a method for controlling single electrons within “quantum dots that run logic gates.” According to Dr. Tuomo Tanttu of UNSW Engineering, “I was trying to really accurately operate a two-qubit gate, iterating through a lot of different devices, slightly different geometries, different materials stacks and different control techniques, then this strange peak popped up. It looked like the rate of rotation for one of the qubits was speeding up, which I’d never seen in four years of running these experiments.”

The new technique manipulates the spin of an electron using electrical, rather than magnetic, fields. The researchers believe this method could make it easier to scale up quantum computer chips to a billion qubits. Diraq’s Dr. Will Gilbert adds, “This is a new way to manipulate qubits, and it’s less bulky to build – you don’t need to fabricate cobalt micro-magnets or an antenna right next to the qubits to generate the control effect. It removes the requirement of placing extra structures around each gate. so, there’s less clutter.”