Aleksei Yu. Dmitriev

Highly stable aluminum air-bridges with stiffeners

  1. Aleksey N. Bolgar,
  2. Daria A. Kalacheva,
  3. Viktor B. Lubsanov,
  4. Aleksei Yu. Dmitriev,
  5. Evgenia S. Alekseeva,
  6. Evgeny V. Korostylev,
  7. and Oleg V. Astafiev
Air-bridges play a critical role in the performance of microwave circuits integrated with superconducting quantum bits, and their mechanical stability is predominant for reliable operation.
This study is devoted to the technological issues that lead to air-bridge instability. We propose an optimized bridge geometry designed to enhance mechanical resilience. Through systematic testing, we established that bridges incorporating this novel geometry achieved complete stability for lengths up to 170 micrometers in our technological processes. The findings provide an insight into the problem and a practical solution for technologists that faced with the challenges of air-bridge stability. The implementation of our technology has the potential to significantly improve the mechanical robustness of air-bridges in multi-qubit circuits for quantum computation.
arxiv pdf

Mixing of coherent waves on a single three-level artificial atom

  1. Teresa Hönigl-Decrinis,
  2. Ilya V. Antonov,
  3. Rais Shaikhadarov,
  4. Vladimir N. Antonov,
  5. Aleksei Yu. Dmitriev,
  6. and Oleg V. Astafiev
We report coherent frequency conversion in the gigahertz range via three-wave mixing on a single artificial atom in open space. All frequencies involved are in vicinity of transition
frequencies of the three-level atom. A cyclic configuration of levels is therefore essential, which we have realised with an artificial atom based on the flux qubit geometry. The atom is continuously driven at two transition frequencies and we directly measure the coherent emission at the sum or difference frequency. Our approach enables coherent conversion of the incoming fields into the coherent emission at a designed frequency in prospective devices of quantum electronics.
arxiv pdf