Mach-Zehnder Interferometry in a Strongly Driven Superconducting Qubit

作者：William D. Oliver, Yang Yu, Janice C. Lee, Karl K. Berggren, Leonid Levitov, Terry P. Orlando · 发表于：Science · 年份：2005 · DOI：10.1126/science.1119678 · 被引用次数：459 · 研究领域：Quantum Information and Cryptography、Quantum optics and atomic interactions、Quantum and electron transport phenomena

We demonstrate Mach-Zehnder-type interferometry in a superconducting flux qubit. The qubit is a tunable artificial atom, the ground and excited states of which exhibit an avoided crossing. Strongly driving the qubit with harmonic excitation sweeps it through the avoided crossing two times per period. Because the induced Landau-Zener transitions act as coherent beamsplitters, the accumulated phase between transitions, which varies with microwave amplitude, results in quantum interference fringes for n = 1 to 20 photon transitions. The generalization of optical Mach-Zehnder interferometry, performed in qubit phase space, provides an alternative means to manipulate and characterize the qubit in the strongly driven regime.