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.

Superfluid Helium Weak Link as Josephson-like Element

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 Surrey and Jens Koch of Northwestern University. This potential advancement differs from prevalent qubit research centered on superconducting circuits, instead leveraging the unique properties of superfluid helium. The device, detailed in recent work, relies on quantized oscillations within a superfluid weak link coupled to a mechanical element, offering a charge-neutral alternative to traditional qubit designs.