Quantum information storage using tunable flux qubits

作者：Matthias Steffen, Frederico Brito, David P. DiVincenzo, Matthew Farinelli, George Keefe, M. B. Ketchen, Shwetank Kumar, Frank Milliken, Mary Beth Rothwell, Jim Rozen, R. H. Koch · 发表于：Journal of Physics Condensed Matter · 年份：2010 · DOI：10.1088/0953-8984/22/5/053201 · 被引用次数：15 · 研究领域：Quantum Information and Cryptography、Quantum and electron transport phenomena、Quantum Computing Algorithms and Architecture

We present details and results for a superconducting quantum bit (qubit) design in which a tunable flux qubit is coupled strongly to a transmission line. Quantum information storage in the transmission line is demonstrated with a dephasing time of T(2)∼ 2.5 µs. However, energy lifetimes of the qubit are found to be short (∼ 10 ns) and not consistent with predictions. Several design and material changes do not affect qubit coherence times. In order to determine the cause of these short coherence times, we fabricated standard flux qubits based on a design which was previously successfully used by others. Initial results show significantly improved coherence times, possibly implicating losses associated with the large size of our qubit.