(HPC) Physicists have produced a new type of qubit that can be switched from a stable idle mode to a fast calculation mode. The concept would also allow a large number of qubits to be combined into a powerful quantum computer, as researchers from the University of Basel and TU Eindhoven have reported.
The new type of qubit has a stable but slow state that is suitable for storing quantum information. However, the researchers were also able to switch the qubit into a much faster but less stable manipulation mode by applying an electrical voltage. In this state, the qubits can be used to process information quickly.
In the new type of qubit, these spins can be selectively coupled – via a photon, for example – to other spins by tuning their resonant frequencies. This capability is vital, since the construction of a powerful quantum computer requires the ability to selectively control and interconnect many individual qubits. Scalability is particularly necessary to reduce the error rate in quantum calculations.
The work was carried out as part of the National Centre of Competence in Research (NCCR) SPIN, which was launched in 2020. The NCCR SPIN is working on scalable spin qubits in semiconductor silicon and germanium nanostructures, and developing small and fast qubits for a universal quantum computer. The SPIN network encompasses not only EPFL and ETH Zurich, but also the industry partner IBM Research – and brings together research groups in the areas of experimental and theoretical physics, materials science, engineering sciences and computer science.