1
|
Zheng H, Cheung LY, Sangwan N, Kononov A, Haller R, Ridderbos J, Ciaccia C, Ungerer JH, Li A, Bakkers EP, Baumgartner A, Schönenberger C. Coherent Control of a Few-Channel Hole Type Gatemon Qubit. NANO LETTERS 2024; 24:7173-7179. [PMID: 38848282 PMCID: PMC11194827 DOI: 10.1021/acs.nanolett.4c00770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Revised: 05/03/2024] [Accepted: 05/06/2024] [Indexed: 06/09/2024]
Abstract
Gatemon qubits are the electrically tunable cousins of superconducting transmon qubits. In this work, we demonstrate the full coherent control of a gatemon qubit based on hole carriers in a Ge/Si core/shell nanowire, with the longest coherence times in group IV material gatemons to date. The key to these results is a high-quality Josephson junction obtained using a straightforward and reproducible annealing technique. We demonstrate that the transport through the narrow junction is dominated by only two quantum channels, with transparencies up to unity. This novel qubit platform holds great promise for quantum information applications, not only because it incorporates technologically relevant materials, but also because it provides new opportunities, like an ultrastrong spin-orbit coupling in the few-channel regime of Josephson junctions.
Collapse
Affiliation(s)
- Han Zheng
- Quantum-
and Nanoelectronics Lab, Department of Physics, University of Basel, 4056 Basel, Switzerland
| | - Luk Yi Cheung
- Quantum-
and Nanoelectronics Lab, Department of Physics, University of Basel, 4056 Basel, Switzerland
| | - Nikunj Sangwan
- Quantum-
and Nanoelectronics Lab, Department of Physics, University of Basel, 4056 Basel, Switzerland
| | - Artem Kononov
- Quantum-
and Nanoelectronics Lab, Department of Physics, University of Basel, 4056 Basel, Switzerland
| | - Roy Haller
- Quantum-
and Nanoelectronics Lab, Department of Physics, University of Basel, 4056 Basel, Switzerland
| | - Joost Ridderbos
- MESA+
Institute for Nanotechnology University of Twente, 7500 AE Enschede, The Netherlands
| | - Carlo Ciaccia
- Quantum-
and Nanoelectronics Lab, Department of Physics, University of Basel, 4056 Basel, Switzerland
| | - Jann Hinnerk Ungerer
- Quantum-
and Nanoelectronics Lab, Department of Physics, University of Basel, 4056 Basel, Switzerland
| | - Ang Li
- Department
of Applied Physics, Eindhoven University
of Technology, 5600 MB Eindhoven, The Netherlands
| | - Erik P.A.M. Bakkers
- Department
of Applied Physics, Eindhoven University
of Technology, 5600 MB Eindhoven, The Netherlands
| | - Andreas Baumgartner
- Quantum-
and Nanoelectronics Lab, Department of Physics, University of Basel, 4056 Basel, Switzerland
- Swiss
Nanoscience Institute, University of Basel, 4056 Basel, Switzerland
| | - Christian Schönenberger
- Quantum-
and Nanoelectronics Lab, Department of Physics, University of Basel, 4056 Basel, Switzerland
- Swiss
Nanoscience Institute, University of Basel, 4056 Basel, Switzerland
| |
Collapse
|
2
|
Schneider L, Ton KT, Ioannidis I, Neuhaus-Steinmetz J, Posske T, Wiesendanger R, Wiebe J. Proximity superconductivity in atom-by-atom crafted quantum dots. Nature 2023; 621:60-65. [PMID: 37587348 PMCID: PMC10482682 DOI: 10.1038/s41586-023-06312-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 06/12/2023] [Indexed: 08/18/2023]
Abstract
Gapless materials in electronic contact with superconductors acquire proximity-induced superconductivity in a region near the interface1,2. Numerous proposals build on this addition of electron pairing to originally non-superconducting systems and predict intriguing phases of matter, including topological3-7, odd-frequency8, nodal-point9 or Fulde-Ferrell-Larkin-Ovchinnikov10 superconductivity. Here we investigate the most miniature example of the proximity effect on only a single spin-degenerate quantum level of a surface state confined in a quantum corral11 on a superconducting substrate, built atom by atom by a scanning tunnelling microscope. Whenever an eigenmode of the corral is pitched close to the Fermi energy by adjusting the size of the corral, a pair of particle-hole symmetric states enters the gap of the superconductor. We identify these as spin-degenerate Andreev bound states theoretically predicted 50 years ago by Machida and Shibata12, which had-so far-eluded detection by tunnel spectroscopy but were recently shown to be relevant for transmon qubit devices13,14. We further find that the observed anticrossings of the in-gap states are a measure of proximity-induced pairing in the eigenmodes of the quantum corral. Our results have direct consequences on the interpretation of impurity-induced in-gap states in superconductors, corroborate concepts to induce superconductivity into surface states and further pave the way towards superconducting artificial lattices.
Collapse
Affiliation(s)
- Lucas Schneider
- Department of Physics, Universität Hamburg, Hamburg, Germany.
| | - Khai That Ton
- Department of Physics, Universität Hamburg, Hamburg, Germany
| | - Ioannis Ioannidis
- I. Institute for Theoretical Physics, Universität Hamburg, Hamburg, Germany
- The Hamburg Centre for Ultrafast Imaging, Hamburg, Germany
| | | | - Thore Posske
- I. Institute for Theoretical Physics, Universität Hamburg, Hamburg, Germany
- The Hamburg Centre for Ultrafast Imaging, Hamburg, Germany
| | | | - Jens Wiebe
- Department of Physics, Universität Hamburg, Hamburg, Germany
| |
Collapse
|
3
|
Fatemi V, Kurilovich PD, Hays M, Bouman D, Connolly T, Diamond S, Frattini NE, Kurilovich VD, Krogstrup P, Nygård J, Geresdi A, Glazman LI, Devoret MH. Microwave Susceptibility Observation of Interacting Many-Body Andreev States. PHYSICAL REVIEW LETTERS 2022; 129:227701. [PMID: 36493424 DOI: 10.1103/physrevlett.129.227701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 09/13/2022] [Indexed: 06/17/2023]
Abstract
Electrostatic charging affects the many-body spectrum of Andreev states, yet its influence on their microwave properties has not been elucidated. We developed a circuit quantum electrodynamics probe that, in addition to transition spectroscopy, measures the microwave susceptibility of different states of a semiconductor nanowire weak link with a single dominant (spin-degenerate) Andreev level. We found that the microwave susceptibility does not exhibit a particle-hole symmetry, which we qualitatively explain as an influence of Coulomb interaction. Moreover, our state-selective measurement reveals a large, π-phase shifted contribution to the response common to all many-body states which can be interpreted as arising from a phase-dependent continuum in the superconducting density of states.
Collapse
Affiliation(s)
- V Fatemi
- Departments of Physics and Applied Physics, Yale University, New Haven, Connecticut 06520, USA
| | - P D Kurilovich
- Departments of Physics and Applied Physics, Yale University, New Haven, Connecticut 06520, USA
| | - M Hays
- Departments of Physics and Applied Physics, Yale University, New Haven, Connecticut 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
| | - T Connolly
- Departments of Physics and Applied Physics, Yale University, New Haven, Connecticut 06520, USA
| | - S Diamond
- Departments of Physics and Applied Physics, Yale University, New Haven, Connecticut 06520, USA
| | - N E Frattini
- Departments of Physics and Applied Physics, Yale University, New Haven, Connecticut 06520, USA
| | - V D Kurilovich
- Departments of Physics and Applied Physics, Yale University, New Haven, Connecticut 06520, USA
| | - P Krogstrup
- 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 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
| | - L I Glazman
- Departments of Physics and Applied Physics, Yale University, New Haven, Connecticut 06520, USA
| | - M H Devoret
- Departments of Physics and Applied Physics, Yale University, New Haven, Connecticut 06520, USA
| |
Collapse
|
4
|
Schmitt TW, Connolly MR, Schleenvoigt M, Liu C, Kennedy O, Chávez-Garcia JM, Jalil AR, Bennemann B, Trellenkamp S, Lentz F, Neumann E, Lindström T, de Graaf SE, Berenschot E, Tas N, Mussler G, Petersson KD, Grützmacher D, Schüffelgen P. Integration of Topological Insulator Josephson Junctions in Superconducting Qubit Circuits. NANO LETTERS 2022; 22:2595-2602. [PMID: 35235321 DOI: 10.1021/acs.nanolett.1c04055] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The integration of semiconductor Josephson junctions (JJs) in superconducting quantum circuits provides a versatile platform for hybrid qubits and offers a powerful way to probe exotic quasiparticle excitations. Recent proposals for using circuit quantum electrodynamics (cQED) to detect topological superconductivity motivate the integration of novel topological materials in such circuits. Here, we report on the realization of superconducting transmon qubits implemented with (Bi0.06Sb0.94)2Te3 topological insulator (TI) JJs using ultrahigh vacuum fabrication techniques. Microwave losses on our substrates, which host monolithically integrated hardmasks used for the selective area growth of TI nanostructures, imply microsecond limits to relaxation times and, thus, their compatibility with strong-coupling cQED. We use the cavity-qubit interaction to show that the Josephson energy of TI-based transmons scales with their JJ dimensions and demonstrate qubit control as well as temporal quantum coherence. Our results pave the way for advanced investigations of topological materials in both novel Josephson and topological qubits.
Collapse
Affiliation(s)
- Tobias W Schmitt
- Institute for Semiconductor Nanoelectronics, Peter Grünberg Institute 9, Forschungszentrum Jülich & Jülich-Aachen Research Alliance (JARA), Forschungszentrum Jülich and RWTH Aachen University, 52428 Jülich, Germany
- JARA-Institute for Green IT, Peter Grünberg Institute 10, Forschungszentrum Jülich and RWTH Aachen University, 52062 Aachen, Germany
| | - Malcolm R Connolly
- Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom
- London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, London WC1H 0AH, United Kingdom
| | - Michael Schleenvoigt
- Institute for Semiconductor Nanoelectronics, Peter Grünberg Institute 9, Forschungszentrum Jülich & Jülich-Aachen Research Alliance (JARA), Forschungszentrum Jülich and RWTH Aachen University, 52428 Jülich, Germany
| | - Chenlu Liu
- Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom
| | - Oscar Kennedy
- London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, London WC1H 0AH, United Kingdom
| | - José M Chávez-Garcia
- Microsoft Quantum Lab Copenhagen and Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Abdur R Jalil
- Institute for Semiconductor Nanoelectronics, Peter Grünberg Institute 9, Forschungszentrum Jülich & Jülich-Aachen Research Alliance (JARA), Forschungszentrum Jülich and RWTH Aachen University, 52428 Jülich, Germany
| | - Benjamin Bennemann
- Institute for Semiconductor Nanoelectronics, Peter Grünberg Institute 9, Forschungszentrum Jülich & Jülich-Aachen Research Alliance (JARA), Forschungszentrum Jülich and RWTH Aachen University, 52428 Jülich, Germany
| | - Stefan Trellenkamp
- Helmholtz Nano Facility, Forschungszentrum Jülich, 52428 Jülich, Germany
| | - Florian Lentz
- Helmholtz Nano Facility, Forschungszentrum Jülich, 52428 Jülich, Germany
| | - Elmar Neumann
- Helmholtz Nano Facility, Forschungszentrum Jülich, 52428 Jülich, Germany
| | - Tobias Lindström
- National Physical Laboratory, Teddington TW11 0LW, United Kingdom
| | | | - Erwin Berenschot
- MESA+ Institute, University of Twente, 7500AE Enschede, The Netherlands
| | - Niels Tas
- MESA+ Institute, University of Twente, 7500AE Enschede, The Netherlands
| | - Gregor Mussler
- Institute for Semiconductor Nanoelectronics, Peter Grünberg Institute 9, Forschungszentrum Jülich & Jülich-Aachen Research Alliance (JARA), Forschungszentrum Jülich and RWTH Aachen University, 52428 Jülich, Germany
| | - Karl D Petersson
- Microsoft Quantum Lab Copenhagen and Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Detlev Grützmacher
- Institute for Semiconductor Nanoelectronics, Peter Grünberg Institute 9, Forschungszentrum Jülich & Jülich-Aachen Research Alliance (JARA), Forschungszentrum Jülich and RWTH Aachen University, 52428 Jülich, Germany
- JARA-Institute for Green IT, Peter Grünberg Institute 10, Forschungszentrum Jülich and RWTH Aachen University, 52062 Aachen, Germany
| | - Peter Schüffelgen
- Institute for Semiconductor Nanoelectronics, Peter Grünberg Institute 9, Forschungszentrum Jülich & Jülich-Aachen Research Alliance (JARA), Forschungszentrum Jülich and RWTH Aachen University, 52428 Jülich, Germany
| |
Collapse
|
5
|
Perla P, Fonseka HA, Zellekens P, Deacon R, Han Y, Kölzer J, Mörstedt T, Bennemann B, Espiari A, Ishibashi K, Grützmacher D, Sanchez AM, Lepsa MI, Schäpers T. Fully in situ Nb/InAs-nanowire Josephson junctions by selective-area growth and shadow evaporation. NANOSCALE ADVANCES 2021; 3:1413-1421. [PMID: 36132855 PMCID: PMC9418346 DOI: 10.1039/d0na00999g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Accepted: 01/17/2021] [Indexed: 06/14/2023]
Abstract
Josephson junctions based on InAs semiconducting nanowires and Nb superconducting electrodes are fabricated in situ by a special shadow evaporation scheme for the superconductor electrode. Compared to other metallic superconductors such as Al, Nb has the advantage of a larger superconducting gap which allows operation at higher temperatures and magnetic fields. Our junctions are fabricated by shadow evaporation of Nb on pairs of InAs nanowires grown selectively on two adjacent tilted Si (111) facets and crossing each other at a small distance. The upper wire relative to the deposition source acts as a shadow mask determining the gap of the superconducting electrodes on the lower nanowire. Electron microscopy measurements show that the fully in situ fabrication method gives a clean InAs/Nb interface. A clear Josephson supercurrent is observed in the current-voltage characteristics, which can be controlled by a bottom gate. The large excess current indicates a high junction transparency. Under microwave radiation, pronounced integer Shapiro steps are observed suggesting a sinusoidal current-phase relation. Owing to the large critical field of Nb, the Josephson supercurrent can be maintained to magnetic fields exceeding 1 T. Our results show that in situ prepared Nb/InAs nanowire contacts are very interesting candidates for superconducting quantum circuits requiring large magnetic fields.
Collapse
Affiliation(s)
- Pujitha Perla
- Peter Grünberg Institut (PGI-9), Forschungszentrum Jülich 52425 Jülich Germany +49 2461 61 2940 +49 2461 61 2668
- JARA-Fundamentals of Future Information Technology, Jülich-Aachen Research Alliance, Forschungszentrum Jülich, RWTH Aachen University Germany
| | - H Aruni Fonseka
- Department of Physics, University of Warwick Coventry CV4 7AL UK
| | - Patrick Zellekens
- Peter Grünberg Institut (PGI-9), Forschungszentrum Jülich 52425 Jülich Germany +49 2461 61 2940 +49 2461 61 2668
- JARA-Fundamentals of Future Information Technology, Jülich-Aachen Research Alliance, Forschungszentrum Jülich, RWTH Aachen University Germany
| | - Russell Deacon
- RIKEN Center for Emergent Matter Science and Advanced Device Laboratory 351-0198 Saitama Japan
| | - Yisong Han
- Department of Physics, University of Warwick Coventry CV4 7AL UK
| | - Jonas Kölzer
- Peter Grünberg Institut (PGI-9), Forschungszentrum Jülich 52425 Jülich Germany +49 2461 61 2940 +49 2461 61 2668
- JARA-Fundamentals of Future Information Technology, Jülich-Aachen Research Alliance, Forschungszentrum Jülich, RWTH Aachen University Germany
| | - Timm Mörstedt
- Peter Grünberg Institut (PGI-9), Forschungszentrum Jülich 52425 Jülich Germany +49 2461 61 2940 +49 2461 61 2668
- JARA-Fundamentals of Future Information Technology, Jülich-Aachen Research Alliance, Forschungszentrum Jülich, RWTH Aachen University Germany
| | - Benjamin Bennemann
- Peter Grünberg Institut (PGI-9), Forschungszentrum Jülich 52425 Jülich Germany +49 2461 61 2940 +49 2461 61 2668
- JARA-Fundamentals of Future Information Technology, Jülich-Aachen Research Alliance, Forschungszentrum Jülich, RWTH Aachen University Germany
| | - Abbas Espiari
- Peter Grünberg Institut (PGI-9), Forschungszentrum Jülich 52425 Jülich Germany +49 2461 61 2940 +49 2461 61 2668
- JARA-Fundamentals of Future Information Technology, Jülich-Aachen Research Alliance, Forschungszentrum Jülich, RWTH Aachen University Germany
| | - Koji Ishibashi
- RIKEN Center for Emergent Matter Science and Advanced Device Laboratory 351-0198 Saitama Japan
| | - Detlev Grützmacher
- Peter Grünberg Institut (PGI-9), Forschungszentrum Jülich 52425 Jülich Germany +49 2461 61 2940 +49 2461 61 2668
- JARA-Fundamentals of Future Information Technology, Jülich-Aachen Research Alliance, Forschungszentrum Jülich, RWTH Aachen University Germany
- Peter Grünberg Institut (PGI-10), Forschungszentrum Jülich 52425 Jülich Germany
| | - Ana M Sanchez
- Department of Physics, University of Warwick Coventry CV4 7AL UK
| | - Mihail Ion Lepsa
- JARA-Fundamentals of Future Information Technology, Jülich-Aachen Research Alliance, Forschungszentrum Jülich, RWTH Aachen University Germany
- Peter Grünberg Institut (PGI-10), Forschungszentrum Jülich 52425 Jülich Germany
| | - Thomas Schäpers
- Peter Grünberg Institut (PGI-9), Forschungszentrum Jülich 52425 Jülich Germany +49 2461 61 2940 +49 2461 61 2668
- JARA-Fundamentals of Future Information Technology, Jülich-Aachen Research Alliance, Forschungszentrum Jülich, RWTH Aachen University Germany
| |
Collapse
|
6
|
Kringhøj A, Winkler GW, Larsen TW, Sabonis D, Erlandsson O, Krogstrup P, van Heck B, Petersson KD, Marcus CM. Andreev Modes from Phase Winding in a Full-Shell Nanowire-Based Transmon. PHYSICAL REVIEW LETTERS 2021; 126:047701. [PMID: 33576664 DOI: 10.1103/physrevlett.126.047701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Accepted: 01/07/2021] [Indexed: 06/12/2023]
Abstract
We investigate transmon qubits made from semiconductor nanowires with a fully surrounding superconducting shell. In the regime of reentrant superconductivity associated with the destructive Little-Parks effect, numerous coherent transitions are observed in the first reentrant lobe, where the shell carries 2π winding of superconducting phase, and are absent in the zeroth lobe. As junction density was increased by gate voltage, qubit coherence was suppressed then lost in the first lobe. These observations and numerical simulations highlight the role of winding-induced Andreev states in the junction.
Collapse
Affiliation(s)
- A Kringhøj
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
- Microsoft Quantum Lab-Copenhagen, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - G W Winkler
- Microsoft Quantum, Station Q, University of California, Santa Barbara, California 93106-6105, USA
| | - T W Larsen
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
- Microsoft Quantum Lab-Copenhagen, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - D Sabonis
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
- Microsoft Quantum Lab-Copenhagen, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - O Erlandsson
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
- Microsoft Quantum Lab-Copenhagen, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - P Krogstrup
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
- Microsoft Quantum Materials Lab-Copenhagen, 2800 Lyngby, Denmark
| | - B van Heck
- Microsoft Quantum Lab Delft, Delft University of Technology, 2600 GA Delft, Netherlands
| | - K D Petersson
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
- Microsoft Quantum Lab-Copenhagen, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - C M Marcus
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
- Microsoft Quantum Lab-Copenhagen, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| |
Collapse
|
7
|
Sabonis D, Erlandsson O, Kringhøj A, van Heck B, Larsen TW, Petkovic I, Krogstrup P, Petersson KD, Marcus CM. Destructive Little-Parks Effect in a Full-Shell Nanowire-Based Transmon. PHYSICAL REVIEW LETTERS 2020; 125:156804. [PMID: 33095630 DOI: 10.1103/physrevlett.125.156804] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 08/26/2020] [Indexed: 06/11/2023]
Abstract
A semiconductor transmon with an epitaxial Al shell fully surrounding an InAs nanowire core is investigated in the low E_{J}/E_{C} regime. Little-Parks oscillations as a function of flux along the hybrid wire axis are destructive, creating lobes of reentrant superconductivity separated by a metallic state at a half quantum of applied flux. In the first lobe, phase winding around the shell can induce topological superconductivity in the core. Coherent qubit operation is observed in both the zeroth and first lobes. Splitting of parity bands by coherent single-electron coupling across the junction is not resolved beyond line broadening, placing a bound on Majorana coupling, E_{M}/h<10 MHz, much smaller than the Josephson coupling E_{J}/h∼4.7 GHz.
Collapse
Affiliation(s)
- Deividas Sabonis
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
- Microsoft Quantum Lab-Copenhagen, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Oscar Erlandsson
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
- Microsoft Quantum Lab-Copenhagen, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Anders Kringhøj
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
- Microsoft Quantum Lab-Copenhagen, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Bernard van Heck
- Microsoft Quantum Lab Delft, Delft University of Technology, 2600 GA Delft, Netherlands
| | - Thorvald W Larsen
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
- Microsoft Quantum Lab-Copenhagen, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Ivana Petkovic
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
- Microsoft Quantum Lab-Copenhagen, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Peter Krogstrup
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
- Microsoft Quantum Materials Lab-Copenhagen, 2800 Lyngby, Denmark
| | - Karl D Petersson
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
- Microsoft Quantum Lab-Copenhagen, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Charles M Marcus
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
- Microsoft Quantum Lab-Copenhagen, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| |
Collapse
|
8
|
Larsen TW, Gershenson ME, Casparis L, Kringhøj A, Pearson NJ, McNeil RPG, Kuemmeth F, Krogstrup P, Petersson KD, Marcus CM. Parity-Protected Superconductor-Semiconductor Qubit. PHYSICAL REVIEW LETTERS 2020; 125:056801. [PMID: 32794832 DOI: 10.1103/physrevlett.125.056801] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 07/09/2020] [Indexed: 06/11/2023]
Abstract
Coherence of superconducting qubits can be improved by implementing designs that protect the parity of Cooper pairs on superconducting islands. Here, we introduce a parity-protected qubit based on voltage-controlled semiconductor nanowire Josephson junctions, taking advantage of the higher harmonic content in the energy-phase relation of few-channel junctions. A symmetric interferometer formed by two such junctions, gate-tuned into balance and frustrated by a half-quantum of applied flux, yields a cos(2φ) Josephson element, reflecting coherent transport of pairs of Cooper pairs. We demonstrate that relaxation of the qubit can be suppressed tenfold by tuning into the protected regime.
Collapse
Affiliation(s)
- T W Larsen
- Center for Quantum Devices and Microsoft Quantum Lab-Copenhagen, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - M E Gershenson
- Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
| | - L Casparis
- Center for Quantum Devices and Microsoft Quantum Lab-Copenhagen, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - A Kringhøj
- Center for Quantum Devices and Microsoft Quantum Lab-Copenhagen, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - N J Pearson
- Center for Quantum Devices and Microsoft Quantum Lab-Copenhagen, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
- Theoretische Physik, ETH Zurich, 8093 Zurich, Switzerland
| | - R P G McNeil
- Center for Quantum Devices and Microsoft Quantum Lab-Copenhagen, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - F Kuemmeth
- Center for Quantum Devices and Microsoft Quantum Lab-Copenhagen, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - P Krogstrup
- Center for Quantum Devices and Microsoft Quantum Lab-Copenhagen, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
- Microsoft Quantum Materials Lab-Copenhagen, 2800 Kongens Lyngby, Denmark
| | - K D Petersson
- Center for Quantum Devices and Microsoft Quantum Lab-Copenhagen, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - C M Marcus
- Center for Quantum Devices and Microsoft Quantum Lab-Copenhagen, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| |
Collapse
|
9
|
Bargerbos A, Uilhoorn W, Yang CK, Krogstrup P, Kouwenhoven LP, de Lange G, van Heck B, Kou A. Observation of Vanishing Charge Dispersion of a Nearly Open Superconducting Island. PHYSICAL REVIEW LETTERS 2020; 124:246802. [PMID: 32639813 DOI: 10.1103/physrevlett.124.246802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 05/15/2020] [Indexed: 06/11/2023]
Abstract
Isolation from the environment determines the extent to which charge is confined on an island, which manifests as Coulomb oscillations, such as charge dispersion. We investigate the charge dispersion of a nanowire transmon hosting a quantum dot in the junction. We observe rapid suppression of the charge dispersion with increasing junction transparency, consistent with the predicted scaling law, which incorporates two branches of the Josephson potential. We find improved qubit coherence times at the point of highest suppression, suggesting novel approaches for building charge-insensitive qubits.
Collapse
Affiliation(s)
- Arno Bargerbos
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, 2600 GA Delft, The Netherlands
| | - Willemijn Uilhoorn
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, 2600 GA Delft, The Netherlands
| | - Chung-Kai Yang
- Microsoft Quantum Lab Delft, 2600 GA Delft, The Netherlands
| | - Peter Krogstrup
- Microsoft Quantum Materials Lab and Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, Kanalvej 7, 2800 Kongens Lyngby, Denmark
| | - Leo P Kouwenhoven
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, 2600 GA Delft, The Netherlands
- Microsoft Quantum Lab Delft, 2600 GA Delft, The Netherlands
| | - Gijs de Lange
- Microsoft Quantum Lab Delft, 2600 GA Delft, The Netherlands
| | | | - Angela Kou
- Microsoft Quantum Lab Delft, 2600 GA Delft, The Netherlands
| |
Collapse
|