Alex Stephane Piedjou Komnang

Characterization of a Transmon Qubit in a 3D Cavity for Quantum Machine Learning and Photon Counting

  1. Alessandro D'Elia,
  2. Boulos Alfakes,
  3. Anas Alkhazaleh,
  4. Leonardo Banchi,
  5. Matteo Beretta,
  6. Stefano Carrazza,
  7. Fabio Chiarello,
  8. Daniele Di Gioacchino,
  9. Andrea Giachero,
  10. Felix Henrich,
  11. Alex Stephane Piedjou Komnang,
  12. Carlo Ligi,
  13. Giovanni Maccarrone,
  14. Massimo Macucci,
  15. Emanuele Palumbo,
  16. Andrea Pasquale,
  17. Luca Piersanti,
  18. Florent Ravaux,
  19. Alessio Rettaroli,
  20. Matteo Robbiati,
  21. Simone Tocci,
  22. and Claudio Gatti
In this paper we report the use of superconducting transmon qubit in a 3D cavity for quantum machine learning and photon counting applications. We first describe the realization and
characterization of a transmon qubit coupled to a 3D resonator, providing a detailed description of the simulation framework and of the experimental measurement of important parameters, like the dispersive shift and the qubit anharmonicity. We then report on a Quantum Machine Learning application implemented on the single-qubit device to fit the u-quark parton distribution function of the proton. In the final section of the manuscript we present a new microwave photon detection scheme based on two qubits coupled to the same 3D resonator. This could in principle decrease the dark count rate, favouring applications like axion dark matter searches.
arxiv pdf

Josephson-based scheme for the detection of microwave photons

  1. Claudio Guarcello,
  2. Alex Stephane Piedjou Komnang,
  3. Carlo Barone,
  4. Alessio Rettaroli,
  5. Claudio Gatti,
  6. Sergio Pagano,
  7. and Giovanni Filatrella
We propose a scheme for the detection of microwave induced photons through current-biased Josephson junction, from the point of view of the statistical decision theory. Our analysis
is based on the numerical study of the zero voltage lifetime distribution in response to a periodic train of pulses, that mimics the absorption of photons. The statistical properties of the detection are retrieved comparing the thermally induced transitions with the distribution of the switchings to the finite voltage state due to the joint action of thermal noise and of the incident pulses. The capability to discriminate the photon arrival can be quantified through the Kumar-Caroll index, which is a good indicator of the Signal-to-Noise-Ratio. The index can be exploited to identify the system parameters best suited for the detection of weak microwave photons.
arxiv pdf