State Tomography of Capacitively Shunted Phase Qubits with High Fidelity

作者：Matthias Steffen, M. Ansmann, R. McDermott, Nadav Y. Katz, Radoslaw C. Bialczak, Erik A. Lucero, M. Neeley, Eva Maria Weig, Andrew N. Cleland, John M. Martinis · 发表于：Physical Review Letters · 年份：2006 · DOI：10.1103/physrevlett.97.050502 · 被引用次数：228 · 研究领域：Quantum Information and Cryptography、Quantum and electron transport phenomena、Quantum Computing Algorithms and Architecture

We introduce a new design concept for superconducting phase quantum bits (qubits) in which we explicitly separate the capacitive element from the Josephson tunnel junction for improved qubit performance. The number of two-level systems that couple to the qubit is thereby reduced by an order of magnitude and the measurement fidelity improves to 90%. This improved design enables the first demonstration of quantum state tomography with superconducting qubits using single-shot measurements.