Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Modern problems in condensed matter sciences

Macroscopic Quantum Effects in the Current-Biased Josephson Junction

Michel Devoret, Daniel ESTEVE, C. Urbina, John M. Martinis, Andrew N. Cleland, John L. Clarke

Published Jan 1, 1992• 9 citations
Publisher
DOI
10.1016/b978-0-444-88041-3.50012-x

Related papers

Macroscopic quantum effects in intrinsic Josephson junction stacks

T. Koyama, Masahiko Machida

Physica C Superconductivity•May 31, 2008•2 citations

Experimental evidence for a current-biased Josephson junction acting as either a macroscopic boson or fermion

P. H. Ouyang, Shiyang He, Y. Z. Wang +4 more

It is well known that elementary particles in the real 3+1 -dimensional world are either bosons or fermions, without exception, and not both. Here, we show that a quantized current-biased Josephson junction (CBJJ), as an artificial macroscopic “particle,” can serve as either a boson or a fermion or the combination, depending on the amplitude of the biased dc current. By using high vacuum two-angle electron beam evaporations, we fabricated CBJJ devices and calibrated their physical parameters by applying low-frequency signal drivings. At 50mK temperature environment, the microwave transmission characteristics of the fabricated CBJJ devices were measured at the low power limit. The experimental results verify the relevant theoretical predictions, i.e., when the bias current is significantly lower than the critical ones of the junctions, the device works in a very linear regime and thus behaves as a harmonic oscillator “boson”; while if the biased current is sufficiently large (especially approaching the junctions' critical currents), the device works manifestly in the nonlinear regime and thus behaves as a two-level artificial atom “fermion.” Therefore, by adjusting the biased dc current, the CBJJ device can be effectively switched from a Bose-type macroscopic particle to a Fermi-type one and thus might open an approach for quantum technology applications at a macroscopic scale. Published by the American Physical Society 2024

Physical Review Research•Mar 4, 2024•9 citations

Effect of an Adjustable Admittance on the Macroscopic Energy Levels of a Current Biased Josephson Junction

Michel Devoret, Daniel Esteve, John M. Martinis +1 more

We have measured the rate of macroscopic quantum tunneling out of the zero voltage state of a current biased Josephson junction shunted by a microwave circuit whose resonant frequencies were varied in situ. By irradiating the junction with microwaves, we find that when the transition frequency between the junction levels coincides with a resonant frequency of the circuit, an hybridization of the junction and circuit quantum states occurs.

Physica Scripta•Jan 1, 1989•14 citations

Macroscopic Quantum Phenomena in Josephson Systems

P. Silvestrini

Springer eBooks•Jan 1, 2000•1 citation

Experimental evidences of a current-biased Josephson junction device can be worked as a macroscopic "Boson" or "Fermion" and the combination

P. H. Ouyang, He, S. R., Y. Z. Wang +4 more

According to the statistical distribution laws, all the elementary particles in the real 3+1-dimensional world must and only be chosen as either bosons or fermions, without exception and not both. Here, we experimentally verified that a quantized current-biased Josephson junction (CBJJ), as an artificial macroscopic "particle", can be served as either boson or fermion, depending on its biased dc-current. By using the high vacuum two-angle electron beam evaporations, we fabricated the CBJJ devices and calibrated their physical parameters by applying low-frequency signal drivings. The microwave transmission characteristics of the fabricated CBJJ devices are analyzed by using the input-output theory and measured at 50mK temperature environment under low power limit. The experimental results verify the theoretical predictions, i.e., when the bias current is significantly lower than the critical one of the junction, the device works in a well linear regime and thus works as a harmonic oscillator, i.e., a "boson"; while if the biased current is sufficiently large (especially approaches to its critical current), the device works manifestly in the nonlinear regime and thus can be served as a two-level artificial atom, i.e., a "fermion". Therefore, by adjusting the biased dc-current, the CBJJ device can be effectively switched from the boson-type macroscopic particle to the fermion-type one, and thus may open the new approach of the superconducting quantum device application.

arXiv:2307.09452•Jul 18, 2023•0 citations

Macroscopic Quantum Tunnelling and Related Effects in Josephson Systems

A. J. Leggett

Springer eBooks•Jan 1, 1984•11 citations
It is well known that elementary particles in the real 3+1 -dimensional world are either bosons or fermions, without exception, and not both. Here, we show that a quantized current-biased Josephson junction (CBJJ), as an artificial macroscopic “particle,” can serve as either a boson or a fermion or the combination, depending on the amplitude of the biased dc current. By using high vacuum two-angle electron beam evaporations, we fabricated CBJJ devices and calibrated their physical parameters by applying low-frequency signal drivings. At 50mK temperature environment, the microwave transmission characteristics of the fabricated CBJJ devices were measured at the low power limit. The experimental results verify the relevant theoretical predictions, i.e., when the bias current is significantly lower than the critical ones of the junctions, the device works in a very linear regime and thus behaves as a harmonic oscillator “boson”; while if the biased current is sufficiently large (especially approaching the junctions' critical currents), the device works manifestly in the nonlinear regime and thus behaves as a two-level artificial atom “fermion.” Therefore, by adjusting the biased dc current, the CBJJ device can be effectively switched from a Bose-type macroscopic particle to a Fermi-type one and thus might open an approach for quantum technology applications at a macroscopic scale. Published by the American Physical Society 2024
According to the statistical distribution laws, all the elementary particles in the real 3+1-dimensional world must and only be chosen as either bosons or fermions, without exception and not both. Here, we experimentally verified that a quantized current-biased Josephson junction (CBJJ), as an artificial macroscopic "particle", can be served as either boson or fermion, depending on its biased dc-current. By using the high vacuum two-angle electron beam evaporations, we fabricated the CBJJ devices and calibrated their physical parameters by applying low-frequency signal drivings. The microwave transmission characteristics of the fabricated CBJJ devices are analyzed by using the input-output theory and measured at 50mK temperature environment under low power limit. The experimental results verify the theoretical predictions, i.e., when the bias current is significantly lower than the critical one of the junction, the device works in a well linear regime and thus works as a harmonic oscillator, i.e., a "boson"; while if the biased current is sufficiently large (especially approaches to its critical current), the device works manifestly in the nonlinear regime and thus can be served as a two-level artificial atom, i.e., a "fermion". Therefore, by adjusting the biased dc-current, the CBJJ device can be effectively switched from the boson-type macroscopic particle to the fermion-type one, and thus may open the new approach of the superconducting quantum device application.