Coherent Josephson Qubit Suitable for Scalable Quantum Integrated Circuits

R. Barends, J. Kelly, A. Megrant, D. Sank, E. Jeffrey, Y. Chen, Y. Yin, B. Chiaro, J. Mutus, C. Neill, P. O’Malley, P. Roushan, J. Wenner, T. C. White, A. N. Cleland, and John M. Martinis
Phys. Rev. Lett. 111, 080502 – Published 22 August 2013
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Abstract

We demonstrate a planar, tunable superconducting qubit with energy relaxation times up to 44μs. This is achieved by using a geometry designed to both minimize radiative loss and reduce coupling to materials-related defects. At these levels of coherence, we find a fine structure in the qubit energy lifetime as a function of frequency, indicating the presence of a sparse population of incoherent, weakly coupled two-level defects. We elucidate this defect physics by experimentally varying the geometry and by a model analysis. Our “Xmon” qubit combines facile fabrication, straightforward connectivity, fast control, and long coherence, opening a viable route to constructing a chip-based quantum computer.

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  • Received 5 April 2013

DOI:https://doi.org/10.1103/PhysRevLett.111.080502

© 2013 American Physical Society

Authors & Affiliations

R. Barends, J. Kelly, A. Megrant, D. Sank, E. Jeffrey, Y. Chen, Y. Yin*, B. Chiaro, J. Mutus, C. Neill, P. O’Malley, P. Roushan, J. Wenner, T. C. White, A. N. Cleland, and John M. Martinis

  • Department of Physics, University of California, Santa Barbara, California 93106, USA

  • *Present address: Department of Physics, Zhejiang University, Hangzhou 310027, China.

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Vol. 111, Iss. 8 — 23 August 2013

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