arXiv subjects

Willemijn Uilhoorn

Publications and source records attributed to Willemijn Uilhoorn.

2 recordsLinked to original sources

arXiv2021

Quasiparticle trapping by orbital effect in a hybrid superconducting-semiconducting circuit

The tunneling of quasiparticles (QPs) across Josephson junctions (JJs) detrimentally affects the coherence of superconducting and charge-parity qubits, and is shown to occur more frequently in magnetic fields. Here we demonstrate the parity lifetime to survive in excess of 50$\,\mathrmμ$s in magnetic fields up to 1$\,$T, utilising a semiconducting nanowire transmon to detect QP tunneling in real time. We exploit gate-tunable QP filters and find magnetic-field-enhanced parity lifetimes, consistent with increased QP trapping by the ungated nanowire due to orbital effects. Our findings highlight the importance of QP trap engineering for building magnetic-field compatible hybrid superconducting circuits.

cond-mat.mes-hall↗

arXiv2020

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 transparency, consistent with the predicted scaling law which incorporates two branches of the Josephson potential. We find improved qubit coherence times at the point of highest suppression, suggesting novel approaches for building charge-insensitive qubits.

cond-mat.mes-hall↗