---
abstract: 'Superconducting persistent-current qubits are quantum-coherent artificial atoms with multiple, tunable energy levels. In the presence of large-amplitude harmonic excitation, the qubit state can be driven through one or more of the constituent energy-level avoided crossings. The resulting Landau-Zener-Stückelberg (LZS) transitions mediate a rich array of quantum-coherent phenomena. We review here three experimental works based on LZS transitions: Mach-Zehnder-type interferometry between repeated LZS transitions, microwave-induced cooling, and amplitude spectroscopy. These experiments exhibit a remarkable agreement with theory, and are extensible to other solid-state and atomic qubit modalities. We anticipate they will find application to qubit state-preparation and control methods for quantum information science and technology.'
author:
- 'W. D. Oliver'
- 'S. O. Valenzuela'
title: |
    Large-amplitude driving of a superconducting artificial atom:\
    Interferometry, cooling, and amplitude spectroscopy
---

Introduction {#intro}
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Superconducting qubits are solid-state artificial atoms, comprising lithographically defined Josephson tunnel junctions and superconducting interconnects. When cooled to milli-Kelvin temperatures, these qubits exhibit quantized states of charge, flux, or junction phase depending on the circuit design parameters [@Clarke88; @Clarke08a]. Associated with these quantized states is a spectrum of energy levels, tunable via an external control parameter, e.g., an applied electric or magnetic field. Although generally only the 