Driving Forbidden Transitions in the Fluxonium Artificial Atom
Uri Vool, Angela Kou, W. Clarke Smith, Nicholas Frattini, Kyle Serniak, Philip Reinhold, Ioan M. Pop, Shyam Shankar, Luigi Frunzio, S. M. Girvin, Michel Devoret · Physical Review Applied · 2018
Superconducting artificial atoms are an emerging platform for the study of coherent quantum physics, and for quantum computation. However, their level-transition properties are currently much simpler than those of true atoms, which limits the quantum systems that can be implemented with this hardware. Here researchers use a nonlinear coupling element to engineer the selection rules of a fluxonium circuit, and thus gain access to previously forbidden transitions. Such a technique allows us to expand the set of quantum operations possible using superconducting circuitry, and is necessary for controlling and measuring physically protected quantum systems.