1
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Benevides R, Drimmer M, Bisson G, Adinolfi F, Lüpke UV, Doeleman HM, Catelani G, Chu Y. Quasiparticle Dynamics in a Superconducting Qubit Irradiated by a Localized Infrared Source. PHYSICAL REVIEW LETTERS 2024; 133:060602. [PMID: 39178459 DOI: 10.1103/physrevlett.133.060602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Accepted: 07/10/2024] [Indexed: 08/25/2024]
Abstract
A known source of decoherence in superconducting qubits is the presence of broken Cooper pairs, or quasiparticles. These can be generated by high-energy radiation, either present in the environment or purposefully introduced, as in the case of some hybrid quantum devices. Here, we systematically study the properties of a transmon qubit under illumination by focused infrared radiation with various powers, durations, and spatial locations. Despite the high energy of incident photons, our observations agree well with a model of low-energy quasiparticle dynamics dominated by trapping. This technique can be used for understanding and potentially mitigating the effects of high-energy radiation on superconducting circuits with a variety of geometries and materials.
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2
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Teixeira W, Mörstedt T, Viitanen A, Kivijärvi H, Gunyhó A, Tiiri M, Kundu S, Sah A, Vadimov V, Möttönen M. Many-excitation removal of a transmon qubit using a single-junction quantum-circuit refrigerator and a two-tone microwave drive. Sci Rep 2024; 14:13755. [PMID: 38877065 PMCID: PMC11178887 DOI: 10.1038/s41598-024-64496-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Accepted: 06/09/2024] [Indexed: 06/16/2024] Open
Abstract
Achieving fast and precise initialization of qubits is a critical requirement for the successful operation of quantum computers. The combination of engineered environments with all-microwave techniques has recently emerged as a promising approach for the reset of superconducting quantum devices. In this work, we experimentally demonstrate the utilization of a single-junction quantum-circuit refrigerator (QCR) for an expeditious removal of several excitations from a transmon qubit. The QCR is indirectly coupled to the transmon through a resonator in the dispersive regime, constituting a carefully engineered environmental spectrum for the transmon. Using single-shot readout, we observe excitation stabilization times down to roughly 500 ns, a 20-fold speedup with QCR and a simultaneous two-tone drive addressing the e-f and f0-g1 transitions of the system. Our results are obtained at a 48-mK fridge temperature and without postselection, fully capturing the advantage of the protocol for the short-time dynamics and the drive-induced detrimental asymptotic behavior in the presence of relatively hot other baths of the transmon. We validate our results with a detailed Liouvillian model truncated up to the three-excitation subspace, from which we estimate the performance of the protocol in optimized scenarios, such as cold transmon baths and fine-tuned driving frequencies. These results pave the way for optimized reset of quantum-electric devices using engineered environments and for dissipation-engineered state preparation.
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Affiliation(s)
- Wallace Teixeira
- QCD Labs, Department of Applied Physics, QTF Centre of Excellence, Aalto University, P.O. Box 13500, FI-00076, Aalto, Finland.
| | - Timm Mörstedt
- QCD Labs, Department of Applied Physics, QTF Centre of Excellence, Aalto University, P.O. Box 13500, FI-00076, Aalto, Finland
| | - Arto Viitanen
- QCD Labs, Department of Applied Physics, QTF Centre of Excellence, Aalto University, P.O. Box 13500, FI-00076, Aalto, Finland
| | - Heidi Kivijärvi
- QCD Labs, Department of Applied Physics, QTF Centre of Excellence, Aalto University, P.O. Box 13500, FI-00076, Aalto, Finland
| | - András Gunyhó
- QCD Labs, Department of Applied Physics, QTF Centre of Excellence, Aalto University, P.O. Box 13500, FI-00076, Aalto, Finland
| | - Maaria Tiiri
- QCD Labs, Department of Applied Physics, QTF Centre of Excellence, Aalto University, P.O. Box 13500, FI-00076, Aalto, Finland
| | - Suman Kundu
- QCD Labs, Department of Applied Physics, QTF Centre of Excellence, Aalto University, P.O. Box 13500, FI-00076, Aalto, Finland
| | - Aashish Sah
- QCD Labs, Department of Applied Physics, QTF Centre of Excellence, Aalto University, P.O. Box 13500, FI-00076, Aalto, Finland
| | - Vasilii Vadimov
- QCD Labs, Department of Applied Physics, QTF Centre of Excellence, Aalto University, P.O. Box 13500, FI-00076, Aalto, Finland
| | - Mikko Möttönen
- QCD Labs, Department of Applied Physics, QTF Centre of Excellence, Aalto University, P.O. Box 13500, FI-00076, Aalto, Finland
- QTF Center of Excellence, VTT Technical Research Centre of Finland Ltd., P.O. Box 1000, FI-02044, VTT, Finland
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3
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Connolly T, Kurilovich PD, Diamond S, Nho H, Bøttcher CGL, Glazman LI, Fatemi V, Devoret MH. Coexistence of Nonequilibrium Density and Equilibrium Energy Distribution of Quasiparticles in a Superconducting Qubit. PHYSICAL REVIEW LETTERS 2024; 132:217001. [PMID: 38856268 DOI: 10.1103/physrevlett.132.217001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 08/10/2023] [Accepted: 03/21/2024] [Indexed: 06/11/2024]
Abstract
The density of quasiparticles typically observed in superconducting qubits exceeds the value expected in equilibrium by many orders of magnitude. Can this out-of-equilibrium quasiparticle density still possess an energy distribution in equilibrium with the phonon bath? Here, we answer this question affirmatively by measuring the thermal activation of charge-parity switching in a transmon qubit with a difference in superconducting gap on the two sides of the Josephson junction. We then demonstrate how the gap asymmetry of the device can be exploited to manipulate its parity.
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Affiliation(s)
- Thomas Connolly
- Departments of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - Pavel D Kurilovich
- Departments of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - Spencer Diamond
- Departments of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - Heekun Nho
- Departments of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - Charlotte G L Bøttcher
- Departments of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - Leonid I Glazman
- Departments of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - Valla Fatemi
- Departments of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA
| | - Michel H Devoret
- Departments of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
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4
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Liu CH, Harrison DC, Patel S, Wilen CD, Rafferty O, Shearrow A, Ballard A, Iaia V, Ku J, Plourde BLT, McDermott R. Quasiparticle Poisoning of Superconducting Qubits from Resonant Absorption of Pair-Breaking Photons. PHYSICAL REVIEW LETTERS 2024; 132:017001. [PMID: 38242669 DOI: 10.1103/physrevlett.132.017001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 11/22/2023] [Accepted: 11/29/2023] [Indexed: 01/21/2024]
Abstract
The ideal superconductor provides a pristine environment for the delicate states of a quantum computer: because there is an energy gap to excitations, there are no spurious modes with which the qubits can interact, causing irreversible decay of the quantum state. As a practical matter, however, there exists a high density of excitations out of the superconducting ground state even at ultralow temperature; these are known as quasiparticles. Observed quasiparticle densities are of order 1 μm^{-3}, tens of orders of magnitude greater than the equilibrium density expected from theory. Nonequilibrium quasiparticles extract energy from the qubit mode and can induce dephasing. Here we show that a dominant mechanism for quasiparticle poisoning is direct absorption of high-energy photons at the qubit junction. We use a Josephson junction-based photon source to controllably dose qubit circuits with millimeter-wave radiation, and we use an interferometric quantum gate sequence to reconstruct the charge parity of the qubit. We find that the structure of the qubit itself acts as a resonant antenna for millimeter-wave radiation, providing an efficient path for photons to generate quasiparticles. A deep understanding of this physics will pave the way to realization of next-generation superconducting qubits that are robust against quasiparticle poisoning.
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Affiliation(s)
- C H Liu
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - D C Harrison
- Intelligence Community Postdoctoral Research Fellowship Program, Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - S Patel
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - C D Wilen
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - O Rafferty
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - A Shearrow
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - A Ballard
- Department of Physics, Syracuse University, Syracuse, New York 13244, USA
| | - V Iaia
- Department of Physics, Syracuse University, Syracuse, New York 13244, USA
| | - J Ku
- Department of Physics, Syracuse University, Syracuse, New York 13244, USA
| | - B L T Plourde
- Department of Physics, Syracuse University, Syracuse, New York 13244, USA
| | - R McDermott
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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5
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Somoroff A, Ficheux Q, Mencia RA, Xiong H, Kuzmin R, Manucharyan VE. Millisecond Coherence in a Superconducting Qubit. PHYSICAL REVIEW LETTERS 2023; 130:267001. [PMID: 37450803 DOI: 10.1103/physrevlett.130.267001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 03/24/2023] [Accepted: 05/10/2023] [Indexed: 07/18/2023]
Abstract
Improving control over physical qubits is a crucial component of quantum computing research. Here we report a superconducting fluxonium qubit with uncorrected coherence time T_{2}^{*}=1.48±0.13 ms, exceeding the state of the art for transmons by an order of magnitude. The average gate fidelity was benchmarked at 0.99991(1). Notably, even in the millisecond range, the coherence time is limited by material absorption and could be further improved with a more rigorous fabrication. Our demonstration may be useful for suppressing errors in the next generation quantum processors.
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Affiliation(s)
- Aaron Somoroff
- Department of Physics, Joint Quantum Institute, and Quantum Materials Center, University of Maryland, College Park, Maryland 20742, USA
| | - Quentin Ficheux
- Department of Physics, Joint Quantum Institute, and Quantum Materials Center, University of Maryland, College Park, Maryland 20742, USA
| | - Raymond A Mencia
- Department of Physics, Joint Quantum Institute, and Quantum Materials Center, University of Maryland, College Park, Maryland 20742, USA
| | - Haonan Xiong
- Department of Physics, Joint Quantum Institute, and Quantum Materials Center, University of Maryland, College Park, Maryland 20742, USA
| | - Roman Kuzmin
- Department of Physics, Joint Quantum Institute, and Quantum Materials Center, University of Maryland, College Park, Maryland 20742, USA
| | - Vladimir E Manucharyan
- Department of Physics, Joint Quantum Institute, and Quantum Materials Center, University of Maryland, College Park, Maryland 20742, USA
- École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
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6
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Pan X, Zhou Y, Yuan H, Nie L, Wei W, Zhang L, Li J, Liu S, Jiang ZH, Catelani G, Hu L, Yan F, Yu D. Engineering superconducting qubits to reduce quasiparticles and charge noise. Nat Commun 2022; 13:7196. [PMID: 36418286 PMCID: PMC9684549 DOI: 10.1038/s41467-022-34727-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Accepted: 11/02/2022] [Indexed: 11/25/2022] Open
Abstract
Identifying, quantifying, and suppressing decoherence mechanisms in qubits are important steps towards the goal of engineering a quantum computer or simulator. Superconducting circuits offer flexibility in qubit design; however, their performance is adversely affected by quasiparticles (broken Cooper pairs). Developing a quasiparticle mitigation strategy compatible with scalable, high-coherence devices is therefore highly desirable. Here we experimentally demonstrate how to control quasiparticle generation by downsizing the qubit, capping it with a metallic cover, and equipping it with suitable quasiparticle traps. Using a flip-chip design, we shape the electromagnetic environment of the qubit above the superconducting gap, inhibiting quasiparticle poisoning. Our findings support the hypothesis that quasiparticle generation is dominated by the breaking of Cooper pairs at the junction, as a result of photon absorption by the antenna-like qubit structure. We achieve record low charge-parity switching rate (<1 Hz). Our aluminium devices also display improved stability with respect to discrete charging events.
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Affiliation(s)
- Xianchuang Pan
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, China.,International Quantum Academy, Shenzhen, Guangdong, China.,Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Yuxuan Zhou
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, China.,International Quantum Academy, Shenzhen, Guangdong, China.,Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, China.,Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Haolan Yuan
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, China.,International Quantum Academy, Shenzhen, Guangdong, China.,Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, China.,Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Lifu Nie
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, China.,International Quantum Academy, Shenzhen, Guangdong, China.,Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Weiwei Wei
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, China.,International Quantum Academy, Shenzhen, Guangdong, China.,Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Libo Zhang
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, China.,International Quantum Academy, Shenzhen, Guangdong, China.,Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Jian Li
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, China.,International Quantum Academy, Shenzhen, Guangdong, China.,Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Song Liu
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, China.,International Quantum Academy, Shenzhen, Guangdong, China.,Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Zhi Hao Jiang
- State Key Laboratory of Millimeter Waves, School of Information Science and Engineering, Southeast University, Nanjing, China
| | - Gianluigi Catelani
- JARA Institute for Quantum Information (PGI-11), Forschungszentrum Jülich, 52425, Jülich, Germany. .,Quantum Research Centre, Technology Innovation Institute, Abu Dhabi, UAE.
| | - Ling Hu
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, China. .,International Quantum Academy, Shenzhen, Guangdong, China. .,Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, China.
| | - Fei Yan
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, China. .,International Quantum Academy, Shenzhen, Guangdong, China. .,Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, China.
| | - Dapeng Yu
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, China.,International Quantum Academy, Shenzhen, Guangdong, China.,Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, China.,Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong, China
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7
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Phonon downconversion to suppress correlated errors in superconducting qubits. Nat Commun 2022; 13:6425. [PMID: 36307415 DOI: 10.1038/s41467-022-33997-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 10/07/2022] [Indexed: 11/09/2022] Open
Abstract
Quantum error correction can preserve quantum information in the presence of local errors, but correlated errors are fatal. For superconducting qubits, high-energy particle impacts from background radioactivity produce energetic phonons that travel throughout the substrate and create excitations above the superconducting ground state, known as quasiparticles, which can poison all qubits on the chip. We use normal metal reservoirs on the chip back side to downconvert phonons to low energies where they can no longer poison qubits. We introduce a pump-probe scheme involving controlled injection of pair-breaking phonons into the qubit chips. We examine quasiparticle poisoning on chips with and without back-side metallization and demonstrate a reduction in the flux of pair-breaking phonons by over a factor of 20. We use a Ramsey interferometer scheme to simultaneously monitor quasiparticle parity on three qubits for each chip and observe a two-order of magnitude reduction in correlated poisoning due to background radiation.
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8
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Danilin S, Barbosa J, Farage M, Zhao Z, Shang X, Burnett J, Ridler N, Li C, Weides M. Engineering the microwave to infrared noise photon flux for superconducting quantum systems. EPJ QUANTUM TECHNOLOGY 2022; 9:1. [PMID: 35098151 PMCID: PMC8761155 DOI: 10.1140/epjqt/s40507-022-00121-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 01/03/2022] [Indexed: 06/14/2023]
Abstract
Electromagnetic filtering is essential for the coherent control, operation and readout of superconducting quantum circuits at milliKelvin temperatures. The suppression of spurious modes around transition frequencies of a few GHz is well understood and mainly achieved by on-chip and package considerations. Noise photons of higher frequencies - beyond the pair-breaking energies - cause decoherence and require spectral engineering before reaching the packaged quantum chip. The external wires that pass into the refrigerator and go down to the quantum circuit provide a direct path for these photons. This article contains quantitative analysis and experimental data for the noise photon flux through coaxial, filtered wiring. The attenuation of the coaxial cable at room temperature and the noise photon flux estimates for typical wiring configurations are provided. Compact cryogenic microwave low-pass filters with CR-110 and Esorb-230 absorptive dielectric fillings are presented along with experimental data at room and cryogenic temperatures up to 70 GHz. Filter cut-off frequencies between 1 to 10 GHz are set by the filter length, and the roll-off is material dependent. The relative dielectric permittivity and magnetic permeability for the Esorb-230 material in the pair-breaking frequency range of 75 to 110 GHz are measured, and the filter properties in this frequency range are calculated. The estimated dramatic suppression of the noise photon flux due to the filter proves its usefulness for experiments with superconducting quantum systems.
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Affiliation(s)
- Sergey Danilin
- James Watt School of Engineering, University of Glasgow, Glasgow, G12 8QQ UK
| | - João Barbosa
- James Watt School of Engineering, University of Glasgow, Glasgow, G12 8QQ UK
| | - Michael Farage
- James Watt School of Engineering, University of Glasgow, Glasgow, G12 8QQ UK
| | - Zimo Zhao
- James Watt School of Engineering, University of Glasgow, Glasgow, G12 8QQ UK
| | - Xiaobang Shang
- National Physical Laboratory, Hampton Road, Teddington, TW11 0LW UK
| | - Jonathan Burnett
- National Physical Laboratory, Hampton Road, Teddington, TW11 0LW UK
| | - Nick Ridler
- National Physical Laboratory, Hampton Road, Teddington, TW11 0LW UK
| | - Chong Li
- James Watt School of Engineering, University of Glasgow, Glasgow, G12 8QQ UK
| | - Martin Weides
- James Watt School of Engineering, University of Glasgow, Glasgow, G12 8QQ UK
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9
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Hays M, Fatemi V, Bouman D, Cerrillo J, Diamond S, Serniak K, Connolly T, Krogstrup P, Nygård J, Levy Yeyati A, Geresdi A, Devoret MH. Coherent manipulation of an Andreev spin qubit. Science 2021; 373:430-433. [PMID: 34437115 DOI: 10.1126/science.abf0345] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Accepted: 05/27/2021] [Indexed: 01/26/2023]
Abstract
Two promising architectures for solid-state quantum information processing are based on electron spins electrostatically confined in semiconductor quantum dots and the collective electrodynamic modes of superconducting circuits. Superconducting electrodynamic qubits involve macroscopic numbers of electrons and offer the advantage of larger coupling, whereas semiconductor spin qubits involve individual electrons trapped in microscopic volumes but are more difficult to link. We combined beneficial aspects of both platforms in the Andreev spin qubit: the spin degree of freedom of an electronic quasiparticle trapped in the supercurrent-carrying Andreev levels of a Josephson semiconductor nanowire. We performed coherent spin manipulation by combining single-shot circuit-quantum-electrodynamics readout and spin-flipping Raman transitions and found a spin-flip time T S = 17 microseconds and a spin coherence time T 2E = 52 nanoseconds. These results herald a regime of supercurrent-mediated coherent spin-photon coupling at the single-quantum level.
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Affiliation(s)
- M Hays
- Department of Applied Physics, Yale University, New Haven, CT 06520, USA.
| | - V Fatemi
- Department of Applied Physics, Yale University, New Haven, CT 06520, USA.
| | - D Bouman
- QuTech and Delft University of Technology, 2600 GA Delft, Netherlands.,Kavli Institute of Nanoscience, Delft University of Technology, 2600 GA Delft, Netherlands
| | - J Cerrillo
- Área de Física Aplicada, Universidad Politécnica de Cartagena, E-30202 Cartagena, Spain.,Departamento de Física Teórica de la Materia Condensada C-V, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - S Diamond
- Department of Applied Physics, Yale University, New Haven, CT 06520, USA
| | - K Serniak
- Department of Applied Physics, Yale University, New Haven, CT 06520, USA
| | - T Connolly
- Department of Applied Physics, Yale University, New Haven, CT 06520, USA
| | - P Krogstrup
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | - J Nygård
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | - A Levy Yeyati
- Departamento de Física Teórica de la Materia Condensada C-V, Universidad Autónoma de Madrid, E-28049 Madrid, Spain.,Condensed Matter Physics Center (IFIMAC) and Instituto Nicolás Cabrera, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - A Geresdi
- QuTech and Delft University of Technology, 2600 GA Delft, Netherlands.,Kavli Institute of Nanoscience, Delft University of Technology, 2600 GA Delft, Netherlands.,Quantum Device Physics Laboratory, Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE 41296 Gothenburg, Sweden
| | - M H Devoret
- Department of Applied Physics, Yale University, New Haven, CT 06520, USA.
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10
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Fatemi V, Devoret MH. Going with the grains. Science 2021; 372:464. [PMID: 33926940 DOI: 10.1126/science.abd8556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Valla Fatemi
- Department of Applied Physics, Yale University, New Haven, CT 06520, USA.
| | - Michel H Devoret
- Department of Applied Physics, Yale University, New Haven, CT 06520, USA
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11
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Meyer JS, Houzet M, Nazarov YV. Dynamical Spin Polarization of Excess Quasiparticles in Superconductors. PHYSICAL REVIEW LETTERS 2020; 125:097006. [PMID: 32915596 DOI: 10.1103/physrevlett.125.097006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 08/13/2020] [Indexed: 06/11/2023]
Abstract
We show that the annihilation dynamics of excess quasiparticles in superconductors may result in the spontaneous formation of large spin-polarized clusters. This presents a novel scenario for spontaneous spin polarization. We estimate the relevant scales for aluminum, finding the feasibility of clusters with total spin S≃10^{4}ℏ that could be spread over microns. The fluctuation dynamics of such large spins may be detected by measuring the flux noise in a loop hosting a cluster.
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Affiliation(s)
- Julia S Meyer
- Univ. Grenoble Alpes, CEA, IRIG-Pheliqs, F-38000 Grenoble, France
| | - Manuel Houzet
- Univ. Grenoble Alpes, CEA, IRIG-Pheliqs, F-38000 Grenoble, France
| | - Yuli V Nazarov
- Kavli Institute of NanoScience, Delft University of Technology, Lorentzweg 1, NL-2628 CJ, Delft, Netherlands
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