Light-dressing of a diatomic superconducting artificial molecule

  1. G.P. Fedorov,
  2. V.B. Yursa,
  3. A. Efimov,
  4. K. Shiianov,
  5. A.Yu. Dmitriev,
  6. I.A. Rodionov,
  7. A.A. Dobronosova,
  8. D.O. Moskalev,
  9. A.A. Pischimova,
  10. and O. V. Astafiev
In this work, we irradiate a superconducting artificial molecule composed of two magnetic-flux-tunable transmons with microwave light while monitoring its state via joint dispersive
readout. At certain fluxes, the molecule demonstrates a complex spectrum deviating qualitatively from the solution of the Schrödinger equation without driving. We reproduce the observed extra spectral lines accurately by numerical simulations, and find them to be a consequence of an Autler-Townes-like effect when a single tone is simultaneously dressing the system and probing the transitions between new eigenstates. We present self-consistent analytical models accounting both these processes at the same time that agree well with both experiment and numerical simulation. This study is an important step towards understanding the behaviour of complex systems of many atoms interacting coherently with strong radiation.