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Macklin C, O'Brien K, Hover D, Schwartz ME, Bolkhovsky V, Zhang X, Oliver WD, Siddiqi I. A near-quantum-limited Josephson traveling-wave parametric amplifier. Science 2015; 350:307-10. [DOI: 10.1126/science.aaa8525] [Citation(s) in RCA: 360] [Impact Index Per Article: 40.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Accepted: 08/19/2015] [Indexed: 11/02/2022]
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Anton SM, Birenbaum JS, O'Kelley SR, Bolkhovsky V, Braje DA, Fitch G, Neeley M, Hilton GC, Cho HM, Irwin KD, Wellstood FC, Oliver WD, Shnirman A, Clarke J. Magnetic flux noise in dc SQUIDs: temperature and geometry dependence. Phys Rev Lett 2013; 110:147002. [PMID: 25167026 DOI: 10.1103/physrevlett.110.147002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Indexed: 06/03/2023]
Abstract
The spectral density S(Φ)(f) = A(2)/(f/1 Hz)(α) of magnetic flux noise in ten dc superconducting quantum interference devices (SQUIDs) with systematically varied geometries shows that α increases as the temperature is lowered; in so doing, each spectrum pivots about a nearly constant frequency. The mean-square flux noise, inferred by integrating the power spectra, grows rapidly with temperature and at a given temperature is approximately independent of the outer dimension of a given SQUID. These results are incompatible with a model based on the random reversal of independent, surface spins.
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Affiliation(s)
- S M Anton
- Department of Physics, University of California, Berkeley, California 94720-7300, USA
| | - J S Birenbaum
- Department of Physics, University of California, Berkeley, California 94720-7300, USA
| | - S R O'Kelley
- Department of Physics, University of California, Berkeley, California 94720-7300, USA
| | - V Bolkhovsky
- MIT Lincoln Laboratory, 244 Wood Street, Lexington, Massachusetts 02420, USA
| | - D A Braje
- MIT Lincoln Laboratory, 244 Wood Street, Lexington, Massachusetts 02420, USA
| | - G Fitch
- MIT Lincoln Laboratory, 244 Wood Street, Lexington, Massachusetts 02420, USA
| | - M Neeley
- MIT Lincoln Laboratory, 244 Wood Street, Lexington, Massachusetts 02420, USA
| | - G C Hilton
- National Institute of Standards and Technology, Boulder, Colorado 80309-044, USA
| | - H-M Cho
- National Institute of Standards and Technology, Boulder, Colorado 80309-044, USA
| | - K D Irwin
- National Institute of Standards and Technology, Boulder, Colorado 80309-044, USA
| | - F C Wellstood
- Department of Physics, University of Maryland, College Park, Maryland 20742, USA
| | - W D Oliver
- MIT Lincoln Laboratory, 244 Wood Street, Lexington, Massachusetts 02420, USA
| | - A Shnirman
- Institut für Theorie der Kondensierten Materie, Karlsruhe Institute of Technology, D-76128 Karlsruhe, Germany
| | - John Clarke
- Department of Physics, University of California, Berkeley, California 94720-7300, USA
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Gustavsson S, Bylander J, Yan F, Forn-Díaz P, Bolkhovsky V, Braje D, Fitch G, Harrabi K, Lennon D, Miloshi J, Murphy P, Slattery R, Spector S, Turek B, Weir T, Welander PB, Yoshihara F, Cory DG, Nakamura Y, Orlando TP, Oliver WD. Driven dynamics and rotary echo of a qubit tunably coupled to a harmonic oscillator. Phys Rev Lett 2012; 108:170503. [PMID: 22680846 DOI: 10.1103/physrevlett.108.170503] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2011] [Indexed: 06/01/2023]
Abstract
We have investigated the driven dynamics of a superconducting flux qubit that is tunably coupled to a microwave resonator. We find that the qubit experiences an oscillating field mediated by off-resonant driving of the resonator, leading to strong modifications of the qubit Rabi frequency. This opens an additional noise channel, and we find that low-frequency noise in the coupling parameter causes a reduction of the coherence time during driven evolution. The noise can be mitigated with the rotary-echo pulse sequence, which, for driven systems, is analogous to the Hahn-echo sequence.
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Affiliation(s)
- S Gustavsson
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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