Mitigation of Quasiparticle Loss in Superconducting Qubits by Phonon Scattering

Quantum error correction will be an essential ingredient in realizing fault-tolerant quantum computing. However, most correction schemes rely on the assumption that errors are sufficiently uncorrelated in space and time. In superconducting qubits, this assumption is drastically violated in the presence of ionizing radiation, which creates bursts...

Gate-tunable superconductivity in hybrid InSb-Pb nanowires

We present a report on hybrid InSb-Pb nanowires that combine high spin-orbit coupling with a high critical field and a large superconducting gap. Material characterization indicates the Pb layer of high crystal quality on the nanowire side facets. Hard induced superconducting gaps and gate-tunable supercurrent are observed in the hybrid...

Radio-Frequency C - V Measurements with Subattofarad Sensitivity

We demonstrate the use of radio-frequency (rf) resonators to measure the capacitance of nanoscale semiconducting devices in field-effect transistor configurations. The rf resonator is attached to the gate or the lead of the device. Consequently, tuning the carrier density in the conducting channel of the device affects the resonance frequency...

Observation of Vanishing Charge Dispersion of a Nearly Open Superconducting Island

Isolation from the environment determines the extent to which charge is confined on an island, which manifests as Coulomb oscillations, such as charge dispersion. We investigate the charge dispersion of a nanowire transmon hosting a quantum dot in the junction. We observe rapid suppression of the charge dispersion with increasing junction...

Gate-Tunable Field-Compatible Fluxonium

Hybrid superconducting circuits, which integrate nonsuperconducting elements into a circuit quantum electrodynamics (cQED) architecture, expand the possible applications of cQED. Building hybrid circuits that work in large magnetic fields presents even further possibilities, such as the probing of spin-polarized Andreev bound states and the...

Triplet-blockaded Josephson supercurrent in double quantum dots

Serial double quantum dots created in semiconductor nanostructures provide a versatile platform for investigating two-electron spin quantum states, which can be tuned by electrostatic gating and an external magnetic field. In this Rapid Communication, we directly measure the supercurrent reversal between adjacent charge states of an InAs...

Broadband microwave spectroscopy of semiconductor nanowire-based Cooper-pair transistors

The Cooper-pair transistor (CPT), a small superconducting island enclosed between two Josephson weak links, is the atomic building block of various superconducting quantum circuits. Utilizing gate-tunable semiconductor channels as weak links, the energy scale associated with the Josephson tunneling can be changed with respect to the charging...

Selective-area chemical beam epitaxy of in-plane InAs one-dimensional channels grown on InP(001), InP(111)B, and InP(011) surfaces

We report on the selective-area chemical beam epitaxial growth of InAs in-plane, one-dimensional (1D) channels using patterned SiO2-coated InP(001), InP(111)B, and InP(011) substrates to establish a scalable platform for topological superconductor networks. Top-view scanning electron micrographs show excellent surface selectivity and...