Microwave amplification via interfering multi-photon processes in a half-waveguide quantum electrodynamics system

  1. Fahad Aziz,
  2. Kuan-Ting Lin,
  3. Ping-Yi Wen,
  4. Samina,
  5. Yu Chen Lin,
  6. Emely Wiegand,
  7. Ching-Ping Lee,
  8. Yu-Ting Cheng,
  9. Ching-Yeh Chen,
  10. Chin-Hsun Chien,
  11. Kai-Min Hsieh,
  12. Yu-Huan Huang,
  13. Ian Hou,
  14. Jeng-Chung Chen,
  15. Yen-Hsiang Lin,
  16. Anton Frisk Kockum,
  17. Guin-Dar Lin,
  18. and Io-Chun Hoi
We investigate the amplification of a microwave probe signal by a superconducting artificial atom, a transmon, strongly coupled to the end of a one-dimensional semi-infinite transmission line. The end of the transmission line acts as a mirror for microwave fields. Due to the weak anharmonicity of the artificial atom, a strong pump field creates multi-photon excitations among the dressed states. Transitions between these dressed states, Rabi sidebands, give rise to either amplification or attenuation of the weak probe. We obtain a maximum amplitude amplification of about 18 %, higher than in any previous experiment with a single artificial atom, due to constructive interference between Rabi sidebands. We also characterize the noise properties of the system by measuring the spectrum of spontaneous emission.

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