Magnifying Quantum Phase Fluctuations with Cooper-Pair Pairing
Remarkably, complex assemblies of superconducting wires, electrodes, and Josephson junctions are compactly described by a handful of collective phase degrees of freedom that behave like quantum particles in a potential. Almost all these circuits operate in the regime where quantum phase fluctuations...
| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
American Physical Society
2022-04-01
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| Series: | Physical Review X |
| Online Access: | http://doi.org/10.1103/PhysRevX.12.021002 |
| _version_ | 1818355714701131776 |
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| author | W. C. Smith M. Villiers A. Marquet J. Palomo M. R. Delbecq T. Kontos P. Campagne-Ibarcq B. Douçot Z. Leghtas |
| author_facet | W. C. Smith M. Villiers A. Marquet J. Palomo M. R. Delbecq T. Kontos P. Campagne-Ibarcq B. Douçot Z. Leghtas |
| author_sort | W. C. Smith |
| collection | DOAJ |
| description | Remarkably, complex assemblies of superconducting wires, electrodes, and Josephson junctions are compactly described by a handful of collective phase degrees of freedom that behave like quantum particles in a potential. Almost all these circuits operate in the regime where quantum phase fluctuations are small—the associated flux is smaller than the superconducting flux quantum—although entering the regime of large fluctuations would have profound implications for metrology and qubit protection. The difficulty arises from the apparent need for circuit impedances vastly exceeding the resistance quantum. Independently, exotic circuit elements that require Cooper pairs to form pairs in order to tunnel have been developed to encode and topologically protect quantum information. In this work, we demonstrate that pairing Cooper pairs magnifies the phase fluctuations of the circuit ground state. We measure a tenfold suppression of flux sensitivity of the first transition energy only, implying a twofold increase in the vacuum phase fluctuations and showing that the ground state is delocalized over several Josephson wells. |
| first_indexed | 2024-12-13T19:45:43Z |
| format | Article |
| id | doaj.art-f72e548b0c1b4709a1cc3d6873fdb7f5 |
| institution | Directory Open Access Journal |
| issn | 2160-3308 |
| language | English |
| last_indexed | 2024-12-13T19:45:43Z |
| publishDate | 2022-04-01 |
| publisher | American Physical Society |
| record_format | Article |
| series | Physical Review X |
| spelling | doaj.art-f72e548b0c1b4709a1cc3d6873fdb7f52022-12-21T23:33:34ZengAmerican Physical SocietyPhysical Review X2160-33082022-04-0112202100210.1103/PhysRevX.12.021002Magnifying Quantum Phase Fluctuations with Cooper-Pair PairingW. C. SmithM. VilliersA. MarquetJ. PalomoM. R. DelbecqT. KontosP. Campagne-IbarcqB. DouçotZ. LeghtasRemarkably, complex assemblies of superconducting wires, electrodes, and Josephson junctions are compactly described by a handful of collective phase degrees of freedom that behave like quantum particles in a potential. Almost all these circuits operate in the regime where quantum phase fluctuations are small—the associated flux is smaller than the superconducting flux quantum—although entering the regime of large fluctuations would have profound implications for metrology and qubit protection. The difficulty arises from the apparent need for circuit impedances vastly exceeding the resistance quantum. Independently, exotic circuit elements that require Cooper pairs to form pairs in order to tunnel have been developed to encode and topologically protect quantum information. In this work, we demonstrate that pairing Cooper pairs magnifies the phase fluctuations of the circuit ground state. We measure a tenfold suppression of flux sensitivity of the first transition energy only, implying a twofold increase in the vacuum phase fluctuations and showing that the ground state is delocalized over several Josephson wells.http://doi.org/10.1103/PhysRevX.12.021002 |
| spellingShingle | W. C. Smith M. Villiers A. Marquet J. Palomo M. R. Delbecq T. Kontos P. Campagne-Ibarcq B. Douçot Z. Leghtas Magnifying Quantum Phase Fluctuations with Cooper-Pair Pairing Physical Review X |
| title | Magnifying Quantum Phase Fluctuations with Cooper-Pair Pairing |
| title_full | Magnifying Quantum Phase Fluctuations with Cooper-Pair Pairing |
| title_fullStr | Magnifying Quantum Phase Fluctuations with Cooper-Pair Pairing |
| title_full_unstemmed | Magnifying Quantum Phase Fluctuations with Cooper-Pair Pairing |
| title_short | Magnifying Quantum Phase Fluctuations with Cooper-Pair Pairing |
| title_sort | magnifying quantum phase fluctuations with cooper pair pairing |
| url | http://doi.org/10.1103/PhysRevX.12.021002 |
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