Geometric Inductor Breaks Resistance Quantum “Limit”

In superconducting circuits, superinductors are employed to suppress charge fluctuations and increase zero-point voltage, enabling features for hardware-protected qubits, metrological standards, and strongly coupled hybrid devices. Conventionally these devices are based on kinetic inductance, and can suffer from nonlinearity, additional complexity due to multiterminal structure, and the limited control and reliability of bottom-up fabrication. Making use of miniaturization and substrate engineering, the authors realize a geometrically defined, single-wavefunction superinductor—a high-performance, innovative circuit element that promises to expand the scope of quantum circuitry.