# Dispersive sensing in hybrid InAs/Al nanowires

## TL;DR

This paper demonstrates dispersive charge sensing in hybrid InAs/Al nanowires, achieving high sensitivity and enabling detection of subgap states, with potential applications in topological quantum computing.

## Contribution

It introduces dispersive sensing techniques in hybrid nanowires and explores their effectiveness in detecting coherent and topological states.

## Key findings

- Charge sensitivity of 1e-3 e/√Hz at 11 MHz bandwidth
- Detection of photon-assisted tunneling dispersively
- Observation of subgap states at 0.6 T magnetic field

## Abstract

Dispersive charge sensing is realized in hybrid semiconductor-superconductor nanowires in gate-defined single- and double-island device geometries. Signal-to-noise ratios (SNRs) were measured both in the frequency and time domain. Frequency-domain measurements were carried out as a function of frequency and power and yield a charge sensitivity of $1 \times 10^{-3} e/\sqrt{\rm Hz}$ for an 11 MHz measurement bandwidth. Time-domain measurements yield SNR > 1 for 20 $\mu$s integration time. At zero magnetic field, photon-assisted tunneling was detected dispersively in a double-island geometry, indicating coherent hybridization of the two superconducting islands. At an axial magnetic field of 0.6 T, subgap states are detected dispersively, demonstrating the suitability of the method for sensing in the topological regime.