Quantum Superposition of Macroscopic Persistent-Current States
10.1126/science.290.5492.773
Crossref journal-article
American Association for the Advancement of Science (AAAS)
Science (221)
Abstract

Microwave spectroscopy experiments have been performed on two quantum levels of a macroscopic superconducting loop with three Josephson junctions. Level repulsion of the ground state and first excited state is found where two classical persistent-current states with opposite polarity are degenerate, indicating symmetric and antisymmetric quantum superpositions of macroscopic states. The two classical states have persistent currents of 0.5 microampere and correspond to the center-of-mass motion of millions of Cooper pairs.

Bibliography

van der Wal, C. H., ter Haar, A. C. J., Wilhelm, F. K., Schouten, R. N., Harmans, C. J. P. M., Orlando, T. P., Lloyd, S., & Mooij, J. E. (2000). Quantum Superposition of Macroscopic Persistent-Current States. Science, 290(5492), 773–777.

Authors 8
  1. Caspar H. van der Wal (first)
  2. A. C. J. ter Haar (additional)
  3. F. K. Wilhelm (additional)
  4. R. N. Schouten (additional)
  5. C. J. P. M. Harmans (additional)
  6. T. P. Orlando (additional)
  7. Seth Lloyd (additional)
  8. J. E. Mooij (additional)
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  43. We thank J. B. Majer A. C. Wallast L. Tian D. S. Crankshaw J. Schmidt A. Wallraff L. Levitov and D. Esteve for help and for stimulating discussions. This work was financially supported by the Dutch Foundation for Fundamental Research on Matter (FOM) the European TMR research network on superconducting nanocircuits (SUPNAN) the U.S. Army Research Office (grant DAAG55-98-1-0369) and the NEDO joint research program (NTDP-98).
Dates
Type When
Created 23 years, 1 month ago (July 27, 2002, 5:47 a.m.)
Deposited 1 year, 7 months ago (Jan. 13, 2024, 5:43 a.m.)
Indexed 4 weeks ago (Aug. 7, 2025, 4:52 a.m.)
Issued 24 years, 10 months ago (Oct. 27, 2000)
Published 24 years, 10 months ago (Oct. 27, 2000)
Published Print 24 years, 10 months ago (Oct. 27, 2000)
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@article{van_der_Wal_2000, title={Quantum Superposition of Macroscopic Persistent-Current States}, volume={290}, ISSN={1095-9203}, url={http://dx.doi.org/10.1126/science.290.5492.773}, DOI={10.1126/science.290.5492.773}, number={5492}, journal={Science}, publisher={American Association for the Advancement of Science (AAAS)}, author={van der Wal, Caspar H. and ter Haar, A. C. J. and Wilhelm, F. K. and Schouten, R. N. and Harmans, C. J. P. M. and Orlando, T. P. and Lloyd, Seth and Mooij, J. E.}, year={2000}, month=oct, pages={773–777} }