Topic: "Amplitude Spectroscopy with a Superconducting Artificial Atom" (Video)
ABSTRACT: Superconducting persistent-current qubits are quantum-coherent artificial atoms with multiple energy levels. In the presence of large-amplitude harmonic excitation, the qubit state can be driven through one or more of the energy-level avoided crossings. The resulting Landau-Zener-Stueckelberg (LZS) transitions mediate quantum-coherent phenomena as a function of the driving-field amplitude. In this talk, we present our recent demonstration of amplitude spectroscopy, a spectroscopy approach based on LZS transitions that monitors the system response to amplitude rather than frequency. This allowed us to probe the energy spectra of our artificial atom over the bandwidth 0.01 - 120 GHz, while driving it at a fixed frequency of only 0.16 GHz. These experiments exhibit a remarkable agreement with theory, and are extensible to other solid-state qubit modalities. We anticipate they will find application to qubit control and state-preparation methods for quantum information science and technology.
 D.M. Berns et al., Nature 455, 51 (Sept 2008)
 M.S. Rudner et al., PRL 101, 190502 (Nov 2008)