Pasquale Scarlino

High-kinetic inductance NbN films for high-quality compact superconducting resonators

  1. Simone Frasca,
  2. Ivo Nikolaev Arabadzhiev,
  3. Sebastien Yves Bros de Puechredon,
  4. Fabian Oppliger,
  5. Vincent Jouanny,
  6. Roberto Musio,
  7. Marco Scigliuzzo,
  8. Fabrizio Minganti,
  9. Pasquale Scarlino,
  10. and Edoardo Charbon
Niobium nitride (NbN) is a particularly promising material for quantum technology applications, as entails the degree of reproducibility necessary for large-scale of superconducting
circuits. We demonstrate that resonators based on NbN thin films present a one-photon internal quality factor above 105 maintaining a high impedance (larger than 2kΩ), with a footprint of approximately 50×100 μm2 and a self-Kerr nonlinearity of few tenths of Hz. These quality factors, mostly limited by losses induced by the coupling to two-level systems, have been maintained for kinetic inductances ranging from tenths to hundreds of pH/square. We also demonstrate minimal variations in the performance of the resonators during multiple cooldowns over more than nine months. Our work proves the versatility of niobium nitride high-kinetic inductance resonators, opening perspectives towards the fabrication of compact, high-impedance and high-quality multimode circuits, with sizable interactions.
arxiv pdf

Strong Coupling Cavity QED with Gate-Defined Double Quantum Dots Enabled by a High Impedance Resonator

  1. Anna Stockklauser,
  2. Pasquale Scarlino,
  3. Jonne Koski,
  4. Simone Gasparinetti,
  5. Christian Kraglund Andersen,
  6. Christian Reichl,
  7. Werner Wegscheider,
  8. Thomas Ihn,
  9. Klaus Ensslin,
  10. and Andreas Wallraff
The strong coupling limit of cavity quantum electrodynamics (QED) implies the capability of a matter-like quantum system to coherently transform an individual excitation into a single
photon within a resonant structure. This not only enables essential processes required for quantum information processing but also allows for fundamental studies of matter-light interaction. In this work we demonstrate strong coupling between the charge degree of freedom in a gate-detuned GaAs double quantum dot (DQD) and a frequency-tunable high impedance resonator realized using an array of superconducting quantum interference devices (SQUIDs). In the resonant regime, we resolve the vacuum Rabi mode splitting of size 2g/2π=238 MHz at a resonator linewidth κ/2π=12 MHz and a DQD charge qubit dephasing rate of γ2/2π=80 MHz extracted independently from microwave spectroscopy in the dispersive regime. Our measurements indicate a viable path towards using circuit based cavity QED for quantum information processing in semiconductor nano-structures.
arxiv pdf