Large-amplitude driving of a superconducting artificial atom: Interferometry, cooling, and amplitude spectroscopy

TL;DR

This paper reviews experiments demonstrating Landau-Zener-Stueckelberg transitions in superconducting qubits, highlighting their applications in interferometry, cooling, and spectroscopy for quantum control.

Contribution

It presents novel experimental techniques leveraging large-amplitude driving to control and measure superconducting qubits, with broad applicability in quantum information science.

Findings

Successful implementation of LZS interferometry in superconducting qubits

Microwave-induced cooling achieved via amplitude modulation

Amplitude spectroscopy reveals detailed energy-level structures

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-Stueckelberg (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.