A micromechanical qubit might last a full second

Researchers at the University of Surrey and Northwestern University are proposing a new type of qubit built not with superconducting circuits, but with quantized oscillations in superfluid helium. The device, consisting of a superfluid weak link and a mechanical element, is predicted to function as a charge-neutral quantum bit with micron-sized dimensions and exhibit millisecond-scale coherence time. This approach leverages both dissipationless mass flow and Josephson tunneling demonstrated in superfluid helium, offering a distinct path toward scalable quantum information processing. The work shows this quantum regime is within reach for a range of device designs. A qubit capable of maintaining quantum coherence for millisecond-scale times, despite being built with micron-sized components, is proposed by Priya Sharma of the University of…