Noise spectroscopy through dynamical decoupling with a superconducting flux qubit

Jonas Bylander*, Simon Gustavsson, Fei Yan, Fumiki Yoshihara, Khalil Harrabi, George Fitch, David G. Cory, Yasunobu Nakamura, Jaw Shen Tsai, William D. Oliver

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

544 Scopus citations


Quantum coherence in natural and artificial spin systems is fundamental to applications ranging from quantum information science to magnetic-resonance imaging and identification. Several multipulse control sequences targeting generalized noise models have been developed to extend coherence by dynamically decoupling a spin system from its noisy environment. In any particular implementation, however, the efficacy of these methods is sensitive to the specific frequency distribution of the noise, suggesting that these same pulse sequences could also be used to probe the noise spectrum directly. Here we demonstrate noise spectroscopy by means of dynamical decoupling using a superconducting qubit with energy-relaxation time T 1 =12 μs. We first demonstrate that dynamical decoupling improves the coherence time T 2 in this system up to the T 2 =2 T 1 limit (pure dephasing times exceeding 100 μs), and then leverage its filtering properties to probe the environmental noise over a frequency (f) range 0.2-20 MHz, observing a 1/f α distribution with α < 1. The characterization of environmental noise has broad utility for spin-resonance applications, enabling the design of optimized coherent-control methods, promoting device and materials engineering, and generally improving coherence.

Original languageEnglish
Pages (from-to)565-570
Number of pages6
JournalNature Physics
Issue number7
StatePublished - Jul 2011

Bibliographical note

Funding Information:
We gratefully acknowledge T. Orlando for support in all aspects of this work. We appreciate M. Biercuk, J. Clarke, L. Levitov and S. Lloyd for discussions, and P. Forn-Diaz and S. Valenzuela for comments on the manuscript. We thank P. Murphy and the LTSE team at MIT Lincoln Laboratory for technical assistance. This work was sponsored by the US Government, the Laboratory for Physical Sciences, the National Science Foundation and the Funding Program for World-Leading Innovative R&D on Science and Technology (FIRST), CREST-JST, MEXT kakenhi ‘Quantum Cybernetics’. Opinions, interpretations, conclusions and recommendations are those of the author(s) and are not necessarily endorsed by the US Government.

ASJC Scopus subject areas

  • Physics and Astronomy (all)


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