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Zhao SYF, Cui X, Volkov PA, Yoo H, Lee S, Gardener JA, Akey AJ, Engelke R, Ronen Y, Zhong R, Gu G, Plugge S, Tummuru T, Kim M, Franz M, Pixley JH, Poccia N, Kim P. Time-reversal symmetry breaking superconductivity between twisted cuprate superconductors. Science 2023; 382:1422-1427. [PMID: 38060675 DOI: 10.1126/science.abl8371] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Accepted: 11/07/2023] [Indexed: 12/23/2023]
Abstract
Twisted interfaces between stacked van der Waals (vdW) cuprate crystals present a platform for engineering superconducting order parameters by adjusting stacking angles. Using a cryogenic assembly technique, we construct twisted vdW Josephson junctions (JJs) at atomically sharp interfaces between Bi2Sr2CaCu2O8+x crystals, with quality approaching the limit set by intrinsic JJs. Near 45° twist angle, we observe fractional Shapiro steps and Fraunhofer patterns, consistent with the existence of two degenerate Josephson ground states related by time-reversal symmetry (TRS). By programming the JJ current bias sequence, we controllably break TRS to place the JJ into either of the two ground states, realizing reversible Josephson diodes without external magnetic fields. Our results open a path to engineering topological devices at higher temperatures.
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Affiliation(s)
- S Y Frank Zhao
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | - Xiaomeng Cui
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | - Pavel A Volkov
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
- Center for Materials Theory, Department of Physics and Astronomy, Rutgers University, Piscataway, NJ 08854, USA
- Department of Physics, University of Connecticut, Storrs, CT 06269, USA
| | - Hyobin Yoo
- Department of Physics, Institute of Emergent Materials, Sogang University, Seoul 04107, Korea
| | - Sangmin Lee
- Department of Materials Science and Engineering, Seoul National University, Seoul 08826, Korea
| | - Jules A Gardener
- Center for Nanoscale Systems, Harvard University, Cambridge, MA 02138, USA
| | - Austin J Akey
- Center for Nanoscale Systems, Harvard University, Cambridge, MA 02138, USA
| | - Rebecca Engelke
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | - Yuval Ronen
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | - Ruidan Zhong
- Department of Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - Genda Gu
- Department of Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - Stephan Plugge
- Department of Physics and Astronomy and Stewart Blusson Quantum Matter Institute, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Tarun Tummuru
- Department of Physics and Astronomy and Stewart Blusson Quantum Matter Institute, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Miyoung Kim
- Department of Materials Science and Engineering, Seoul National University, Seoul 08826, Korea
| | - Marcel Franz
- Department of Physics and Astronomy and Stewart Blusson Quantum Matter Institute, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Jedediah H Pixley
- Center for Materials Theory, Department of Physics and Astronomy, Rutgers University, Piscataway, NJ 08854, USA
| | - Nicola Poccia
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
- Leibniz Institute for Solid State and Materials Research Dresden (IFW Dresden), 01069 Dresden, Germany
| | - Philip Kim
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
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Plugge S, Lantagne-Hurtubise É, Franz M. Revival Dynamics in a Traversable Wormhole. Phys Rev Lett 2020; 124:221601. [PMID: 32567928 DOI: 10.1103/physrevlett.124.221601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 05/05/2020] [Accepted: 05/11/2020] [Indexed: 06/11/2023]
Abstract
Quantum effects can stabilize wormhole solutions in general relativity, allowing information and matter to be transported between two connected spacetimes. Here we study the revival dynamics of signals sent between two weakly coupled quantum chaotic systems, represented as identical Sachdev-Ye-Kitaev models, that realize holographically a traversable wormhole in anti-de Sitter spacetime AdS_{2} for large number N of particles. In this limit we find clear signatures of wormhole behavior: an excitation created in one system is quickly scrambled under its unitary dynamics, and is reassembled in the other system after a characteristic time consistent with holography predictions. This leads to revival oscillations that at low but finite temperature decay as a power law in time. For small N we also observe revivals and show that they arise from a different, nongravitational mechanism.
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Affiliation(s)
- Stephan Plugge
- Department of Physics and Astronomy & Stewart Blusson Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Étienne Lantagne-Hurtubise
- Department of Physics and Astronomy & Stewart Blusson Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
- Kavli Institute for Theoretical Physics, University of California, Santa Barbara, California 93106, USA
| | - Marcel Franz
- Department of Physics and Astronomy & Stewart Blusson Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
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Sela E, Oreg Y, Plugge S, Hartman N, Lüscher S, Folk J. Detecting the Universal Fractional Entropy of Majorana Zero Modes. Phys Rev Lett 2019; 123:147702. [PMID: 31702171 DOI: 10.1103/physrevlett.123.147702] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Indexed: 06/10/2023]
Abstract
A pair of Majorana zero modes (MZMs) constitutes a nonlocal qubit whose entropy is log2. Upon strongly coupling one of the constituent MZMs to a reservoir with a continuous density of states, a universal entropy change of 1/2log2 is expected to be observed across an intermediate temperature plateau. We adapt the entropy-measurement scheme that was the basis of a recent experiment by Hartman et al. [Nat. Phys. 14, 1083 (2018)10.1038/s41567-018-0250-5] to the case of a proximitized topological system hosting MZMs and propose a method to measure this 1/2log2 entropy change-an unambiguous signature of the nonlocal nature of the topological state. This approach offers an experimental strategy to distinguish MZMs from non topological states.
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Affiliation(s)
- Eran Sela
- Raymond and Beverly Sackler School of Physics and Astronomy, Tel-Aviv University, IL-69978 Tel Aviv, Israel
- Stewart Blusson Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia V6T1Z4, Canada
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T1Z1, Canada
| | - Yuval Oreg
- Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Stephan Plugge
- Stewart Blusson Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia V6T1Z4, Canada
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T1Z1, Canada
| | - Nikolaus Hartman
- Stewart Blusson Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia V6T1Z4, Canada
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T1Z1, Canada
| | - Silvia Lüscher
- Stewart Blusson Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia V6T1Z4, Canada
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T1Z1, Canada
| | - Joshua Folk
- Stewart Blusson Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia V6T1Z4, Canada
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T1Z1, Canada
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Zazunov A, Plugge S, Egger R. Fermi-Liquid Approach for Superconducting Kondo Problems. Phys Rev Lett 2018; 121:207701. [PMID: 30500242 DOI: 10.1103/physrevlett.121.207701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Indexed: 06/09/2023]
Abstract
We present a Fermi liquid approach to superconducting Kondo problems applicable when the Kondo temperature is large compared to the superconducting gap. To illustrate the theory, we study the current-phase relation and the Andreev level spectrum for an Anderson impurity between two s-wave superconductors. In the particle-hole symmetric Kondo limit, we find a 4π periodic Andreev spectrum. The 4π periodicity persists under a small voltage bias which however causes an asymmetric distortion of Andreev levels. The latter distinguishes the present 4π effect from the one in topological Majorana junctions.
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Affiliation(s)
- Alex Zazunov
- Institut für Theoretische Physik, Heinrich-Heine-Universität, D-40225 Düsseldorf, Germany
| | - Stephan Plugge
- Institut für Theoretische Physik, Heinrich-Heine-Universität, D-40225 Düsseldorf, Germany
| | - Reinhold Egger
- Institut für Theoretische Physik, Heinrich-Heine-Universität, D-40225 Düsseldorf, Germany
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Landau LA, Plugge S, Sela E, Altland A, Albrecht SM, Egger R. Towards Realistic Implementations of a Majorana Surface Code. Phys Rev Lett 2016; 116:050501. [PMID: 26894694 DOI: 10.1103/physrevlett.116.050501] [Citation(s) in RCA: 3] [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: 09/17/2015] [Indexed: 06/05/2023]
Abstract
Surface codes have emerged as promising candidates for quantum information processing. Building on the previous idea to realize the physical qubits of such systems in terms of Majorana bound states supported by topological semiconductor nanowires, we show that the basic code operations, namely projective stabilizer measurements and qubit manipulations, can be implemented by conventional tunnel conductance probes and charge pumping via single-electron transistors, respectively. The simplicity of the access scheme suggests that a functional code might be in close experimental reach.
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Affiliation(s)
- L A Landau
- Raymond and Beverly Sackler School of Physics and Astronomy, Tel-Aviv University, Tel Aviv 69978, Israel
| | - S Plugge
- Institut für Theoretische Physik, Heinrich-Heine-Universität, D-40225 Düsseldorf, Germany
| | - E Sela
- Raymond and Beverly Sackler School of Physics and Astronomy, Tel-Aviv University, Tel Aviv 69978, Israel
| | - A Altland
- Institut für Theoretische Physik, Universität zu Köln, Zülpicher Straße 77, D-50937 Köln, Germany
| | - S M Albrecht
- Center for Quantum Devices and Station Q-Copenhagen, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark
| | - R Egger
- Institut für Theoretische Physik, Heinrich-Heine-Universität, D-40225 Düsseldorf, Germany
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