O. V. Kibis

Stimulated emission for a three-level artificial atom in waveguide quantum electrodynamics

  1. O. A. Chuikin,
  2. Ya. S. Greenberg,
  3. V. V. Taravkova,
  4. and O. V. Kibis
This work is devoted to a theoretical study of the interaction of a quantum three-level ladder system with a continuous electromagnetic field in a one-dimensional open waveguide. Weconsider a situation closely resembling stimulated emission – the scattering of a single-photon exponential pulse by an excited three-level emitter. Using the real-space formalism, we obtain an analytical expression for the wavefunction of our system. We show that, for the low anharmonicity of a three-level system inherent to a transmon (the most common type of artificial atom), the influence of the third level can have a significant effect on the system’s behavior. Namely, the presence of the third level largely suppresses the stimulated emission effect if the relative anharmonicity is lower than |αr|<4%. However, for a three-level system, it is possible to obtain correlation effects such as photon bunching in the reflected field, which can also be 'switched off' by tuning the incident photon parameters.[/expand]
arxiv pdf

Decay of transmon qubit strongly coupled with a continuum

  1. Ya. S. Greenberg,
  2. A. A. Shtygashev,
  3. and O. V. Kibis
We investigate the decay of three-level artificial atom, a superconducting transmon qubit which interacts with a continuum of modes in an open one-dimensional waveguide. For strong
interaction of transmon with a continuum we obtain analytical expressions for the frequency shifts and widths of the resonances the values of which are calculated numerically for the Gaussian density of states. We show that the coupling between the second level and ground state of a transmon significantly influences the decay of the third transmon level.
arxiv pdf