1
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Chen C, Tran J, McFadden A, Simmonds R, Saito K, Chu ED, Morales D, Suezaki V, Hou Y, Aumentado J, Lee PA, Moodera JS, Wei P. Signatures of a spin-active interface and a locally enhanced Zeeman field in a superconductor-chiral material heterostructure. SCIENCE ADVANCES 2024; 10:eado4875. [PMID: 39178249 PMCID: PMC11343014 DOI: 10.1126/sciadv.ado4875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2024] [Accepted: 07/19/2024] [Indexed: 08/25/2024]
Abstract
A localized Zeeman field, intensified at heterostructure interfaces, could play a crucial role in a broad area including spintronics and unconventional superconductors. Conventionally, the generation of a local Zeeman field is achieved through magnetic exchange coupling with a magnetic material. However, magnetic elements often introduce defects, which could weaken or destroy superconductivity. Alternatively, the coupling between a superconductor with strong spin-orbit coupling and a nonmagnetic chiral material could serve as a promising approach to generate a spin-active interface. Here, we leverage an interface superconductor, namely, induced superconductivity in noble metal surface states, to probe the spin-active interface. Our results unveil an enhanced interface Zeeman field, which selectively closes the surface superconducting gap while preserving the bulk superconducting pairing. The chiral material, i.e., trigonal tellurium, also induces Andreev bound states (ABS) exhibiting spin polarization. The field dependence of ABS manifests a substantially enhanced interface Landé g-factor (geff ~ 12), thereby corroborating the enhanced interface Zeeman energy.
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Affiliation(s)
- Cliff Chen
- Department of Physics and Astronomy, University of California, Riverside, CA 92521, USA
| | - Jason Tran
- Department of Physics and Astronomy, University of California, Riverside, CA 92521, USA
| | - Anthony McFadden
- National Institute of Standards and Technology, Boulder, CO 80305, USA
| | - Raymond Simmonds
- National Institute of Standards and Technology, Boulder, CO 80305, USA
| | - Keisuke Saito
- Rigaku Americas, a Division of Rigaku Americas Holding, The Woodlands, TX 77381, USA
| | - En-De Chu
- Department of Physics and Astronomy, University of California, Riverside, CA 92521, USA
| | - Daniel Morales
- Department of Physics and Astronomy, University of California, Riverside, CA 92521, USA
| | - Varrick Suezaki
- Department of Physics and Astronomy, University of California, Riverside, CA 92521, USA
| | - Yasen Hou
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Francis Bitter Magnet Laboratory, and Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Joe Aumentado
- National Institute of Standards and Technology, Boulder, CO 80305, USA
| | - Patrick A. Lee
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Jagadeesh S. Moodera
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Francis Bitter Magnet Laboratory, and Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Peng Wei
- Department of Physics and Astronomy, University of California, Riverside, CA 92521, USA
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2
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Sagi O, Crippa A, Valentini M, Janik M, Baghumyan L, Fabris G, Kapoor L, Hassani F, Fink J, Calcaterra S, Chrastina D, Isella G, Katsaros G. A gate tunable transmon qubit in planar Ge. Nat Commun 2024; 15:6400. [PMID: 39080279 PMCID: PMC11289319 DOI: 10.1038/s41467-024-50763-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Accepted: 07/15/2024] [Indexed: 08/02/2024] Open
Abstract
Gate-tunable transmons (gatemons) employing semiconductor Josephson junctions have recently emerged as building blocks for hybrid quantum circuits. In this study, we present a gatemon fabricated in planar Germanium. We induce superconductivity in a two-dimensional hole gas by evaporating aluminum atop a thin spacer, which separates the superconductor from the Ge quantum well. The Josephson junction is then integrated into an Xmon circuit and capacitively coupled to a transmission line resonator. We showcase the qubit tunability in a broad frequency range with resonator and two-tone spectroscopy. Time-domain characterizations reveal energy relaxation and coherence times up to 75 ns. Our results, combined with the recent advances in the spin qubit field, pave the way towards novel hybrid and protected qubits in a group IV, CMOS-compatible material.
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Affiliation(s)
- Oliver Sagi
- Institute of Science and Technology Austria, Klosterneuburg, Austria.
| | - Alessandro Crippa
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, Pisa, Italy
| | - Marco Valentini
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Marian Janik
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Levon Baghumyan
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Giorgio Fabris
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Lucky Kapoor
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Farid Hassani
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Johannes Fink
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | | | | | - Giovanni Isella
- L-NESS, Physics Department, Politecnico di Milano, Como, Italy
| | - Georgios Katsaros
- Institute of Science and Technology Austria, Klosterneuburg, Austria
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3
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Nigro A, Jutzi E, Oppliger F, De Palma F, Olsen C, Ruiz-Caridad A, Gadea G, Scarlino P, Zardo I, Hofmann A. Demonstration of Microwave Resonators and Double Quantum Dots on Optimized Reverse-Graded Ge/SiGe Heterostructures. ACS APPLIED ELECTRONIC MATERIALS 2024; 6:5094-5100. [PMID: 39070085 PMCID: PMC11270818 DOI: 10.1021/acsaelm.4c00654] [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: 04/14/2024] [Revised: 05/23/2024] [Accepted: 06/12/2024] [Indexed: 07/30/2024]
Abstract
One of the most promising platforms for the realization of spin-based quantum computing are planar germanium quantum wells embedded between silicon-germanium barriers. To achieve comparably thin stacks with little surface roughness, this type of heterostructure can be grown using the so-called reverse linear grading approach, where the growth starts with a virtual germanium substrate followed by a graded silicon-germanium alloy with an increasing silicon content. However, the compatibility of such reverse-graded heterostructures with superconducting microwave resonators has not yet been demonstrated. Here, we report on the successful realization of well-controlled double quantum dots and high-quality coplanar waveguide resonators on the same reverse-graded Ge/SiGe heterostructure.
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Affiliation(s)
- Arianna Nigro
- Physics
Department, University of Basel, Klingelbergstrasse 82, Basel CH-4056, Switzerland
| | - Eric Jutzi
- Physics
Department, University of Basel, Klingelbergstrasse 82, Basel CH-4056, Switzerland
| | - Fabian Oppliger
- Hybrid
Quantum Circuits Laboratory, Institute of Physics, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne 1015, Switzerland
| | - Franco De Palma
- Hybrid
Quantum Circuits Laboratory, Institute of Physics, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne 1015, Switzerland
| | - Christian Olsen
- Physics
Department, University of Basel, Klingelbergstrasse 82, Basel CH-4056, Switzerland
| | - Alicia Ruiz-Caridad
- Physics
Department, University of Basel, Klingelbergstrasse 82, Basel CH-4056, Switzerland
| | - Gerard Gadea
- Physics
Department, University of Basel, Klingelbergstrasse 82, Basel CH-4056, Switzerland
- Swiss
Nanoscience Institute, Klingelbergstrasse 82, Basel CH-4056, Switzerland
| | - Pasquale Scarlino
- Hybrid
Quantum Circuits Laboratory, Institute of Physics, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne 1015, Switzerland
| | - Ilaria Zardo
- Physics
Department, University of Basel, Klingelbergstrasse 82, Basel CH-4056, Switzerland
- Swiss
Nanoscience Institute, Klingelbergstrasse 82, Basel CH-4056, Switzerland
| | - Andrea Hofmann
- Physics
Department, University of Basel, Klingelbergstrasse 82, Basel CH-4056, Switzerland
- Swiss
Nanoscience Institute, Klingelbergstrasse 82, Basel CH-4056, Switzerland
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4
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Cleland AY, Wollack EA, Safavi-Naeini AH. Studying phonon coherence with a quantum sensor. Nat Commun 2024; 15:4979. [PMID: 38862502 PMCID: PMC11167028 DOI: 10.1038/s41467-024-48306-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 04/25/2024] [Indexed: 06/13/2024] Open
Abstract
Nanomechanical oscillators offer numerous advantages for quantum technologies. Their integration with superconducting qubits shows promise for hardware-efficient quantum error-correction protocols involving superpositions of mechanical coherent states. Limitations of this approach include mechanical decoherence processes, particularly two-level system (TLS) defects, which have been widely studied using classical fields and detectors. In this manuscript, we use a superconducting qubit as a quantum sensor to perform phonon number-resolved measurements on a piezoelectrically coupled phononic crystal cavity. This enables a high-resolution study of mechanical dissipation and dephasing in coherent states of variable size (n ¯ ≃ 1 - 10 phonons). We observe nonexponential relaxation and state size-dependent reduction of the dephasing rate, which we attribute to TLS. Using a numerical model, we reproduce the dissipation signatures (and to a lesser extent, the dephasing signatures) via emission into a small ensemble (N = 5) of rapidly dephasing TLS. Our findings comprise a detailed examination of TLS-induced phonon decoherence in the quantum regime.
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Affiliation(s)
- Agnetta Y Cleland
- Department of Applied Physics and Ginzton Laboratory, Stanford University 348 Via Pueblo Mall, Stanford, CA, 94305, USA
| | - E Alex Wollack
- Department of Applied Physics and Ginzton Laboratory, Stanford University 348 Via Pueblo Mall, Stanford, CA, 94305, USA
| | - Amir H Safavi-Naeini
- Department of Applied Physics and Ginzton Laboratory, Stanford University 348 Via Pueblo Mall, Stanford, CA, 94305, USA.
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5
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Ganjam S, Wang Y, Lu Y, Banerjee A, Lei CU, Krayzman L, Kisslinger K, Zhou C, Li R, Jia Y, Liu M, Frunzio L, Schoelkopf RJ. Surpassing millisecond coherence in on chip superconducting quantum memories by optimizing materials and circuit design. Nat Commun 2024; 15:3687. [PMID: 38693124 PMCID: PMC11063213 DOI: 10.1038/s41467-024-47857-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 04/12/2024] [Indexed: 05/03/2024] Open
Abstract
The performance of superconducting quantum circuits for quantum computing has advanced tremendously in recent decades; however, a comprehensive understanding of relaxation mechanisms does not yet exist. In this work, we utilize a multimode approach to characterizing energy losses in superconducting quantum circuits, with the goals of predicting device performance and improving coherence through materials, process, and circuit design optimization. Using this approach, we measure significant reductions in surface and bulk dielectric losses by employing a tantalum-based materials platform and annealed sapphire substrates. With this knowledge we predict the relaxation times of aluminum- and tantalum-based transmon qubits, and find that they are consistent with experimental results. We additionally optimize device geometry to maximize coherence within a coaxial tunnel architecture, and realize on-chip quantum memories with single-photon Ramsey times of 2.0 - 2.7 ms, limited by their energy relaxation times of 1.0 - 1.4 ms. These results demonstrate an advancement towards a more modular and compact coaxial circuit architecture for bosonic qubits with reproducibly high coherence.
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Affiliation(s)
- Suhas Ganjam
- Departments of Applied Physics and Physics, Yale University, New Haven, 06511, CT, USA.
- Yale Quantum Institute, Yale University, New Haven, 06511, CT, USA.
| | - Yanhao Wang
- Departments of Applied Physics and Physics, Yale University, New Haven, 06511, CT, USA
- Yale Quantum Institute, Yale University, New Haven, 06511, CT, USA
| | - Yao Lu
- Departments of Applied Physics and Physics, Yale University, New Haven, 06511, CT, USA
- Yale Quantum Institute, Yale University, New Haven, 06511, CT, USA
| | - Archan Banerjee
- Departments of Applied Physics and Physics, Yale University, New Haven, 06511, CT, USA
- Yale Quantum Institute, Yale University, New Haven, 06511, CT, USA
| | - Chan U Lei
- Departments of Applied Physics and Physics, Yale University, New Haven, 06511, CT, USA
- Yale Quantum Institute, Yale University, New Haven, 06511, CT, USA
| | - Lev Krayzman
- Departments of Applied Physics and Physics, Yale University, New Haven, 06511, CT, USA
- Yale Quantum Institute, Yale University, New Haven, 06511, CT, USA
| | - Kim Kisslinger
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, 11973, NY, USA
| | - Chenyu Zhou
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, 11973, NY, USA
| | - Ruoshui Li
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, 11973, NY, USA
| | - Yichen Jia
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, 11973, NY, USA
| | - Mingzhao Liu
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, 11973, NY, USA
| | - Luigi Frunzio
- Departments of Applied Physics and Physics, Yale University, New Haven, 06511, CT, USA
- Yale Quantum Institute, Yale University, New Haven, 06511, CT, USA
| | - Robert J Schoelkopf
- Departments of Applied Physics and Physics, Yale University, New Haven, 06511, CT, USA.
- Yale Quantum Institute, Yale University, New Haven, 06511, CT, USA.
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6
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Vine W, Kringhøj A, Savytskyi M, Parker D, Schenkel T, Johnson BC, McCallum JC, Morello A, Pla JJ. Latched detection of zeptojoule spin echoes with a kinetic inductance parametric oscillator. SCIENCE ADVANCES 2024; 10:eadm7624. [PMID: 38578995 PMCID: PMC10997192 DOI: 10.1126/sciadv.adm7624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Accepted: 03/01/2024] [Indexed: 04/07/2024]
Abstract
When strongly pumped at twice their resonant frequency, nonlinear resonators develop a high-amplitude intracavity field, a phenomenon known as parametric self-oscillations. The boundary over which this instability occurs can be extremely sharp and thereby presents an opportunity for realizing a detector. Here, we operate such a device based on a superconducting microwave resonator whose nonlinearity is engineered from kinetic inductance. The device indicates the absorption of low-power microwave wavepackets by transitioning to a self-oscillating state. Using calibrated pulses, we measure the detection efficiency to zeptojoule energy wavepackets. We then apply it to measurements of electron spin resonance, using an ensemble of 209Bi donors in silicon that are inductively coupled to the resonator. We achieve a latched readout of the spin signal with an amplitude that is five hundred times greater than the underlying spin echoes.
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Affiliation(s)
- Wyatt Vine
- School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, New South Wales 2052, Australia
| | - Anders Kringhøj
- School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, New South Wales 2052, Australia
| | - Mykhailo Savytskyi
- School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, New South Wales 2052, Australia
| | - Daniel Parker
- School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, New South Wales 2052, Australia
| | - Thomas Schenkel
- Accelerator Technology and Applied Physics Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Brett C. Johnson
- School of Science, RMIT University, Melbourne, Victoria 3001, Australia
| | - Jeffrey C. McCallum
- School of Physics, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Andrea Morello
- School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, New South Wales 2052, Australia
| | - Jarryd J. Pla
- School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, New South Wales 2052, Australia
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7
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Ungerer JH, Sarmah D, Kononov A, Ridderbos J, Haller R, Cheung LY, Schönenberger C. Performance of high impedance resonators in dirty dielectric environments. EPJ QUANTUM TECHNOLOGY 2023; 10:41. [PMID: 37810533 PMCID: PMC10558395 DOI: 10.1140/epjqt/s40507-023-00199-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 09/27/2023] [Indexed: 10/10/2023]
Abstract
High-impedance resonators are a promising contender for realizing long-distance entangling gates between spin qubits. Often, the fabrication of spin qubits relies on the use of gate dielectrics which are detrimental to the quality of the resonator. Here, we investigate loss mechanisms of high-impedance NbTiN resonators in the vicinity of thermally grown SiO2 and Al2O3 fabricated by atomic layer deposition. We benchmark the resonator performance in elevated magnetic fields and at elevated temperatures and find that the internal quality factors are limited by the coupling between the resonator and two-level systems of the employed oxides. Nonetheless, the internal quality factors of high-impedance resonators exceed 103 in all investigated oxide configurations which implies that the dielectric configuration would not limit the performance of resonators integrated in a spin-qubit device. Because these oxides are commonly used for spin qubit device fabrication, our results allow for straightforward integration of high-impedance resonators into spin-based quantum processors. Hence, these experiments pave the way for large-scale, spin-based quantum computers.
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Affiliation(s)
- J. H. Ungerer
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
- Swiss Nanoscience Institute, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - D. Sarmah
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - A. Kononov
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - J. Ridderbos
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
- Present Address: NanoElectronics Group, MESA Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - R. Haller
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - L. Y. Cheung
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - C. Schönenberger
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
- Swiss Nanoscience Institute, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
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8
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Zikiy EV, Ivanov AI, Smirnov NS, Moskalev DO, Polozov VI, Matanin AR, Malevannaya EI, Echeistov VV, Konstantinova TG, Rodionov IA. High-Q trenched aluminum coplanar resonators with an ultrasonic edge microcutting for superconducting quantum devices. Sci Rep 2023; 13:15536. [PMID: 37730848 PMCID: PMC10511541 DOI: 10.1038/s41598-023-42332-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 09/08/2023] [Indexed: 09/22/2023] Open
Abstract
Dielectric losses are one of the key factors limiting the coherence of superconducting qubits. The impact of materials and fabrication steps on dielectric losses can be evaluated using coplanar waveguide (CPW) microwave resonators. Here, we report on superconducting CPW microwave resonators with internal quality factors systematically exceeding 5 × 106 at high powers and 2 × 106 (with the best value of 4.4 × 106) at low power. Such performance is demonstrated for 100-nm-thick aluminum resonators with 7-10.5 um center trace on high-resistivity silicon substrates commonly used in Josephson-junction based quantum circuit. We investigate internal quality factors of the resonators with both dry and wet aluminum etching, as well as deep and isotropic reactive ion etching of silicon substrate. Josephson junction compatible CPW resonators fabrication process with both airbridges and silicon substrate etching is proposed. Finally, we demonstrate the effect of airbridges' positions and extra process steps on the overall dielectric losses. The best quality factors are obtained for the wet etched aluminum resonators and isotropically removed substrate with the proposed ultrasonic metal edge microcutting.
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Affiliation(s)
- E V Zikiy
- FMN Laboratory, Bauman Moscow State Technical University, Moscow, 105005, Russia
- Dukhov Automatics Research Institute (VNIIA), Moscow, 127055, Russia
| | - A I Ivanov
- FMN Laboratory, Bauman Moscow State Technical University, Moscow, 105005, Russia
- Dukhov Automatics Research Institute (VNIIA), Moscow, 127055, Russia
| | - N S Smirnov
- FMN Laboratory, Bauman Moscow State Technical University, Moscow, 105005, Russia
- Dukhov Automatics Research Institute (VNIIA), Moscow, 127055, Russia
| | - D O Moskalev
- FMN Laboratory, Bauman Moscow State Technical University, Moscow, 105005, Russia
- Dukhov Automatics Research Institute (VNIIA), Moscow, 127055, Russia
| | - V I Polozov
- FMN Laboratory, Bauman Moscow State Technical University, Moscow, 105005, Russia
| | - A R Matanin
- FMN Laboratory, Bauman Moscow State Technical University, Moscow, 105005, Russia
- Dukhov Automatics Research Institute (VNIIA), Moscow, 127055, Russia
| | - E I Malevannaya
- FMN Laboratory, Bauman Moscow State Technical University, Moscow, 105005, Russia
| | - V V Echeistov
- FMN Laboratory, Bauman Moscow State Technical University, Moscow, 105005, Russia
| | - T G Konstantinova
- FMN Laboratory, Bauman Moscow State Technical University, Moscow, 105005, Russia
| | - I A Rodionov
- FMN Laboratory, Bauman Moscow State Technical University, Moscow, 105005, Russia.
- Dukhov Automatics Research Institute (VNIIA), Moscow, 127055, Russia.
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9
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Wu Y, Ding Z, Xiong K, Feng J. High-quality superconducting α-Ta film sputtered on the heated silicon substrate. Sci Rep 2023; 13:12810. [PMID: 37550325 PMCID: PMC10406942 DOI: 10.1038/s41598-023-39420-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Accepted: 07/25/2023] [Indexed: 08/09/2023] Open
Abstract
Intrigued by the discovery of the long lifetime in the α-Ta/Al2O3-based Transmon qubit, researchers recently found α-Ta film is a promising platform for fabricating multi-qubits with long coherence time. To meet the requirements for integrating superconducting quantum circuits, the ideal method is to grow α-Ta film on a silicon substrate compatible with industrial manufacturing. Here we report the α-Ta film sputter-grown on Si (100) with a low-loss superconducting TiNx buffer layer. The α-Ta film with a large growth temperature window has a good crystalline character. The superconducting critical transition temperature (Tc) and residual resistivity ratio (RRR) in the α-Ta film grown at 500 °C are higher than that in the α-Ta film grown at room temperature (RT). These results provide crucial experimental clues toward understanding the connection between the superconductivity and the materials' properties in the α-Ta film and open a new route for producing a high-quality α-Ta film on silicon substrate for future industrial superconducting quantum computers.
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Affiliation(s)
- Yanfu Wu
- Gusu Laboratory of Materials, Suzhou, 215123, China
| | | | - Kanglin Xiong
- Gusu Laboratory of Materials, Suzhou, 215123, China.
- Suzhou Institute of Nano-Tech and Nano-Bionics, CAS, Suzhou, 215123, China.
| | - Jiagui Feng
- Gusu Laboratory of Materials, Suzhou, 215123, China.
- Suzhou Institute of Nano-Tech and Nano-Bionics, CAS, Suzhou, 215123, China.
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10
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Alghadeer M, Banerjee A, Hajr A, Hussein H, Fariborzi H, Rao SG. Surface Passivation of Niobium Superconducting Quantum Circuits Using Self-Assembled Monolayers. ACS APPLIED MATERIALS & INTERFACES 2023; 15:2319-2328. [PMID: 36573579 DOI: 10.1021/acsami.2c15667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Superconducting coplanar waveguide (CPW) microwave resonators in quantum circuits are the best components for reading and changing the state of artificial atoms because of their excellent coupling to quantum systems. This coupling forms the basis of the developing circuit quantum electrodynamic architecture. In quantum processors, oscillators are used to store and transmit quantum information using microwave-frequency wave packets. However, the presence of amorphous thin-film defects is deleterious and can result in an irrevocable loss of coherent information with uncontrolled degrees of freedom. Although there has been extensive research into techniques to reduce the coherent loss of such devices, the precise structure of amorphous dielectric layers on surfaces and interfaces and their associated loss mechanism are being actively studied. In particular, planar superconducting resonators are very sensitive to defects on their surfaces, such as two-level systems in oxidized metals and nonequilibrium quasiparticles, making these devices suitable probes for the different loss mechanisms. In this work, we present the design, fabrication, and characterization of Nb CPW resonators with different surface treatments with self-assembled monolayers (SAMs), which mitigate the growth of oxides in superconducting circuits. We demonstrate SAM-passivated resonators having internal quality factors of greater than 106 at a single-photon excitation power (measured at 100 mK), which were probed using scanning electron microscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy to demonstrate the efficiency of our surface treatment. Finally, we compared the improvements in the experimental quality factors to those obtained by numerical simulation.
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Affiliation(s)
- Mohammed Alghadeer
- Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran31261, Saudi Arabia
- Quantum Nanoelectronics Laboratory, Department of Physics, University of California, Berkeley, California94720, United States
- CEMSE Division, King Abdullah University of Science and Technology, Thuwal23955, Saudi Arabia
| | - Archan Banerjee
- Quantum Nanoelectronics Laboratory, Department of Physics, University of California, Berkeley, California94720, United States
| | - Ahmed Hajr
- Quantum Nanoelectronics Laboratory, Department of Physics, University of California, Berkeley, California94720, United States
| | - Hussein Hussein
- CEMSE Division, King Abdullah University of Science and Technology, Thuwal23955, Saudi Arabia
| | - Hossein Fariborzi
- CEMSE Division, King Abdullah University of Science and Technology, Thuwal23955, Saudi Arabia
| | - Saleem Ghaffar Rao
- Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran31261, Saudi Arabia
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11
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Murthy AA, Masih Das P, Ribet SM, Kopas C, Lee J, Reagor MJ, Zhou L, Kramer MJ, Hersam MC, Checchin M, Grassellino A, Reis RD, Dravid VP, Romanenko A. Developing a Chemical and Structural Understanding of the Surface Oxide in a Niobium Superconducting Qubit. ACS NANO 2022; 16:17257-17262. [PMID: 36153944 DOI: 10.1021/acsnano.2c07913] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Superconducting thin films of niobium have been extensively employed in transmon qubit architectures. Although these architectures have demonstrated improvements in recent years, further improvements in performance through materials engineering will aid in large-scale deployment. Here, we use information retrieved from secondary ion mass spectrometry and electron microscopy to conduct a detailed assessment of the surface oxide that forms in ambient conditions for transmon test qubit devices patterned from a niobium film. We observe that this oxide exhibits a varying stoichiometry with NbO and NbO2 found closer to the niobium film/oxide interface and Nb2O5 found closer to the surface. In terms of structural analysis, we find that the Nb2O5 region is semicrystalline in nature and exhibits randomly oriented grains on the order of 1-3 nm corresponding to monoclinic N-Nb2O5 that are dispersed throughout an amorphous matrix. Using fluctuation electron microscopy, we are able to map the relative crystallinity in the Nb2O5 region with nanometer spatial resolution. Through this correlative method, we observe that the highly disordered regions are more likely to contain oxygen vacancies and exhibit weaker bonds between the niobium and oxygen atoms. Based on these findings, we expect that oxygen vacancies likely serve as a decoherence mechanism in quantum systems.
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Affiliation(s)
- Akshay A Murthy
- Superconducting Quantum Materials and Systems Division, Fermi National Accelerator Laboratory (FNAL), Batavia, Illinois 60510, United States
| | - Paul Masih Das
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Stephanie M Ribet
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
- International Institute of Nanotechnology, Northwestern University, Evanston, Illinois 60208, United States
| | - Cameron Kopas
- Rigetti Computing, Berkeley, California 94710, United States
| | - Jaeyel Lee
- Superconducting Quantum Materials and Systems Division, Fermi National Accelerator Laboratory (FNAL), Batavia, Illinois 60510, United States
| | | | - Lin Zhou
- Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011, United States
| | - Matthew J Kramer
- Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011, United States
| | - Mark C Hersam
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
- Department of Electrical and Computer Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Mattia Checchin
- Superconducting Quantum Materials and Systems Division, Fermi National Accelerator Laboratory (FNAL), Batavia, Illinois 60510, United States
| | - Anna Grassellino
- Superconducting Quantum Materials and Systems Division, Fermi National Accelerator Laboratory (FNAL), Batavia, Illinois 60510, United States
| | - Roberto Dos Reis
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
- The NUANCE Center, Northwestern University, Evanston, Illinois 60208, United States
| | - Vinayak P Dravid
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
- International Institute of Nanotechnology, Northwestern University, Evanston, Illinois 60208, United States
- The NUANCE Center, Northwestern University, Evanston, Illinois 60208, United States
| | - Alexander Romanenko
- Superconducting Quantum Materials and Systems Division, Fermi National Accelerator Laboratory (FNAL), Batavia, Illinois 60510, United States
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12
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Malnou M, Aumentado J, Vissers M, Wheeler J, Hubmayr J, Ullom J, Gao J. Performance of a Kinetic Inductance Traveling-Wave Parametric Amplifier at 4 Kelvin: Toward an Alternative to Semiconductor Amplifiers. PHYSICAL REVIEW APPLIED 2022; 17:10.1103/physrevapplied.17.044009. [PMID: 37965129 PMCID: PMC10644704 DOI: 10.1103/physrevapplied.17.044009] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2023]
Abstract
Most microwave readout architectures in quantum computing or sensing rely on a semiconductor amplifier at 4 K, typically a high-electron mobility transistor (HEMT). Despite its remarkable noise performance, a conventional HEMT dissipates several milliwatts of power, posing a practical challenge to scale up the number of qubits or sensors addressed in these architectures. As an alternative, we present an amplification chain consisting of a kinetic inductance traveling-wave parametric amplifier (KITWPA) placed at 4 K, followed by a HEMT placed at 70 K, and demonstrate a chain-added noise T Σ = 6.3 ± 0.5 K between 3.5 and 5.5 GHz. While, in principle, any parametric amplifier can be quantum limited even at 4 K, in practice we find the performance of the KITWPA to be limited by the temperature of its inputs and by an excess of noise T ex = 1.9 K . The dissipation of the rf pump of the KITWPA constitutes the main power load at 4 K and is about 1% that of a HEMT. These combined noise and power dissipation values pave the way for the use of the KITWPA as a replacement for semiconductor amplifiers.
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Affiliation(s)
- M. Malnou
- National Institute of Standards and Technology, Boulder, Colorado 80305, USA
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - J. Aumentado
- National Institute of Standards and Technology, Boulder, Colorado 80305, USA
| | - M.R. Vissers
- National Institute of Standards and Technology, Boulder, Colorado 80305, USA
| | - J.D. Wheeler
- National Institute of Standards and Technology, Boulder, Colorado 80305, USA
| | - J. Hubmayr
- National Institute of Standards and Technology, Boulder, Colorado 80305, USA
| | - J.N. Ullom
- National Institute of Standards and Technology, Boulder, Colorado 80305, USA
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - J. Gao
- National Institute of Standards and Technology, Boulder, Colorado 80305, USA
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
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13
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Kohne M, Li W, Ionescu A, Zhu C, Warncke K. Resolution and characterization of contributions of select protein and coupled solvent configurational fluctuations to radical rearrangement catalysis in coenzyme B 12-dependent ethanolamine ammonia-lyase. Methods Enzymol 2022; 669:229-259. [PMID: 35644173 PMCID: PMC9270175 DOI: 10.1016/bs.mie.2021.12.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Coenzyme B12 (adenosylcobalamin) -dependent ethanolamine ammonia-lyase (EAL) is the signature enzyme in ethanolamine utilization metabolism associated with microbiome homeostasis and disease conditions in the human gut. The enzyme conducts a complex choreography of bond-making/bond-breaking steps that rearrange substrate to products through a radical mechanism, with themes common to other coenzyme B12-dependent and radical enzymes. The methods presented are targeted to test the hypothesis that particular, select protein and coupled solvent configurational fluctuations contribute to enzyme function. The general approach is to correlate enzyme function with an introduced perturbation that alters the properties (for example, degree of concertedness, or collectiveness) of protein and coupled solvent dynamics. Methods for sample preparation and low-temperature kinetic measurements by using temperature-step reaction initiation and time-resolved, full-spectrum electron paramagnetic resonance spectroscopy are detailed. A framework for interpretation of results obtained in ensemble systems under conditions of statistical equilibrium within the reacting, globally unstable state is presented. The temperature-dependence of the first-order rate constants for decay of the cryotrapped paramagnetic substrate radical state in EAL, through the chemical step of radical rearrangement, displays a piecewise-continuous Arrhenius dependence from 203 to 295K, punctuated by a kinetic bifurcation over 219-220K. The results reveal the obligatory contribution of a class of select collective protein and coupled solvent fluctuations to the interconversion of two resolved, sequential configurational substates, on the decay time scale. The select class of collective fluctuations also contributes to the chemical step. The methods and analysis are generally applicable to other coenzyme B12-dependent and related radical enzymes.
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Affiliation(s)
- Meghan Kohne
- Department of Physics, Emory University, Atlanta, GA, United States
| | - Wei Li
- Department of Physics, Emory University, Atlanta, GA, United States
| | - Alina Ionescu
- Department of Physics, Emory University, Atlanta, GA, United States
| | - Chen Zhu
- Department of Physics, Emory University, Atlanta, GA, United States
| | - Kurt Warncke
- Department of Physics, Emory University, Atlanta, GA, United States.
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14
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Antony A, Gustafsson MV, Rajendran A, Benyamini A, Ribeill G, Ohki TA, Hone J, Fong KC. Making high-quality quantum microwave devices with van der Waals superconductors. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 34:103001. [PMID: 34847535 DOI: 10.1088/1361-648x/ac3e9d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 11/30/2021] [Indexed: 06/13/2023]
Abstract
Ultra low-loss microwave materials are crucial for enhancing quantum coherence and scalability of superconducting qubits. Van der Waals (vdW) heterostructure is an attractive platform for quantum devices due to the single-crystal structure of the constituent two-dimensional (2D) layered materials and the lack of dangling bonds at their atomically sharp interfaces. However, new fabrication and characterization techniques are required to determine whether these structures can achieve low loss in the microwave regime. Here we report the fabrication of superconducting microwave resonators using NbSe2that achieve a quality factorQ> 105. This value sets an upper bound that corresponds to a resistance of⩽192μΩwhen considering the additional loss introduced by integrating NbSe2into a standard transmon circuit. This work demonstrates the compatibility of 2D layered materials with high-quality microwave quantum devices.
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Affiliation(s)
- Abhinandan Antony
- Department of Mechanical Engineering, Columbia University, New York, NY 10027, United States of America
| | - Martin V Gustafsson
- Raytheon BBN Technologies, Quantum Engineering and Computing Group, Cambridge, MA 02138, United States of America
| | - Anjaly Rajendran
- Department of Electrical Engineering, Columbia University, New York, NY 10027, United States of America
| | - Avishai Benyamini
- Department of Mechanical Engineering, Columbia University, New York, NY 10027, United States of America
| | - Guilhem Ribeill
- Raytheon BBN Technologies, Quantum Engineering and Computing Group, Cambridge, MA 02138, United States of America
| | - Thomas A Ohki
- Raytheon BBN Technologies, Quantum Engineering and Computing Group, Cambridge, MA 02138, United States of America
| | - James Hone
- Department of Mechanical Engineering, Columbia University, New York, NY 10027, United States of America
| | - Kin Chung Fong
- Raytheon BBN Technologies, Quantum Engineering and Computing Group, Cambridge, MA 02138, United States of America
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15
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Niepce D, Burnett JJ, Kudra M, Cole JH, Bylander J. Stability of superconducting resonators: Motional narrowing and the role of Landau-Zener driving of two-level defects. SCIENCE ADVANCES 2021; 7:eabh0462. [PMID: 34559556 PMCID: PMC8462906 DOI: 10.1126/sciadv.abh0462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 08/05/2021] [Indexed: 06/13/2023]
Abstract
Frequency instability of superconducting resonators and qubits leads to dephasing and time-varying energy loss and hinders quantum processor tune-up. Its main source is dielectric noise originating in surface oxides. Thorough noise studies are needed to develop a comprehensive understanding and mitigation strategy of these fluctuations. We use a frequency-locked loop to track the resonant frequency jitter of three different resonator types—one niobium nitride superinductor, one aluminum coplanar waveguide, and one aluminum cavity—and we observe notably similar random telegraph signal fluctuations. At low microwave drive power, the resonators exhibit multiple, unstable frequency positions, which, for increasing power, coalesce into one frequency due to motional narrowing caused by sympathetic driving of two-level system defects by the resonator. In all three devices, we identify a dominant fluctuator whose switching amplitude (separation between states) saturates with increasing drive power, but whose characteristic switching rate follows the power law dependence of quasi-classical Landau-Zener transitions.
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Affiliation(s)
- David Niepce
- Chalmers University of Technology, Microtechnology, and Nanoscience, SE-41296 Gothenburg, Sweden
| | - Jonathan J. Burnett
- National Physical Laboratory, Hampton Road, Teddington Middlesex TW11 0LW, UK
| | - Marina Kudra
- Chalmers University of Technology, Microtechnology, and Nanoscience, SE-41296 Gothenburg, Sweden
| | - Jared H. Cole
- Chemical and Quantum Physics, School of Science, RMIT University, Melbourne, VIC 3001, Australia
| | - Jonas Bylander
- Chalmers University of Technology, Microtechnology, and Nanoscience, SE-41296 Gothenburg, Sweden
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16
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Ionescu A, Li W, Nforneh B, Warncke K. Coupling of ethanolamine ammonia-lyase protein and solvent dynamics characterized by the temperature-dependence of EPR spin probe mobility and dielectric permittivity. J Chem Phys 2021; 154:175101. [PMID: 34241057 DOI: 10.1063/5.0040341] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Electron paramagnetic resonance (EPR) spectroscopy is used to address the remarkable persistence of the native Arrhenius dependence of the 2-aminopropanol substrate radical rearrangement reaction in B12-dependent ethanolamine ammonia-lyase (EAL) from Salmonella typhimurium from physiological to cryogenic (220 K) temperatures. Two-component TEMPOL spin probe mobility in the presence of 10 mM (0.08% v/v) 2-aminopropanol over 200-265 K demonstrates characteristic concentric aqueous-cosolvent mesodomain and protein-associated domain (PAD, hydration layer) solvent phases around EAL in the frozen solution. The mesodomain formed by the relatively small amount of 2-aminopropanol is highly confined, as shown by an elevated temperature for the order-disorder transition (ODT) in the PAD (230-235 K) and large activation energy for TEMPOL rotation. Addition of 2% v/v dimethylsulfoxide expands the mesodomain, partially relieves PAD confinement, and leads to an ODT at 205-210 K. The ODT is also manifested as a deviation of the temperature-dependence of the EPR amplitude of cob(II)alamin and the substrate radical, bound in the enzyme active site, from Curie law behavior. This is attributed to an increase in sample dielectric permittivity above the ODT at the microwave frequency of 9.5 GHz. The relatively high frequency dielectric response indicates an origin in coupled protein surface group-water fluctuations of the Johari-Goldstein β type that span spatial scales of ∼0.1-10 Å on temporal scales of 10-10-10-7 s. The orthogonal EPR spin probe rotational mobility and solvent dielectric measurements characterize features of EAL protein-solvent dynamical coupling and reveal that excess substrate acts as a fluidizing cryosolvent to enable native enzyme reactivity at cryogenic temperatures.
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Affiliation(s)
- Alina Ionescu
- Department of Physics, Emory University, Atlanta, Georgia 30322-2430, USA
| | - Wei Li
- Department of Physics, Emory University, Atlanta, Georgia 30322-2430, USA
| | - Benjamen Nforneh
- Department of Physics, Emory University, Atlanta, Georgia 30322-2430, USA
| | - Kurt Warncke
- Department of Physics, Emory University, Atlanta, Georgia 30322-2430, USA
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17
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Howe L, Castellanos-Beltran MA, Sirois AJ, Olaya D, Biesecker J, Dresselhaus PD, Benz SP, Hopkins PF. Digital Control of a Superconducting Qubit Using a Josephson Pulse Generator at 3 K. PRX QUANTUM : A PHYSICAL REVIEW JOURNAL 2020; 3:10.1103/prxquantum.3.010350. [PMID: 36726390 PMCID: PMC9888300 DOI: 10.1103/prxquantum.3.010350] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Scaling of quantum computers to fault-tolerant levels relies critically on the integration of energy-efficient, stable, and reproducible qubit control and readout electronics. In comparison to traditional semiconductor-control electronics (TSCE) located at room temperature, the signals generated by rf sources based on Josephson-junctions (JJs) benefit from small device sizes, low power dissipation, intrinsic calibration, superior reproducibility, and insensitivity to ambient fluctuations. Previous experiments to colocate qubits and JJ-based control electronics have resulted in quasiparticle poisoning of the qubit, degrading the coherence and lifetime of the qubit. In this paper, we digitally control a 0.01-K transmon qubit with pulses from a Josephson pulse generator (JPG) located at the 3-K stage of a dilution refrigerator. We directly compare the qubit lifetime T 1, the coherence time T 2 * , and the thermal occupation P th when the qubit is controlled by the JPG circuit versus the TSCE setup. We find agreement to within the daily fluctuations of ±0.5 μs and ±2 μs for T 1 and T 2 * , respectively, and agreement to within the 1% error for P th. Additionally, we perform randomized benchmarking to measure an average JPG gate error of 2.1 × 10-2. In combination with a small device size (< 25 mm2) and low on-chip power dissipation (≪100 μW), these results are an important step toward demonstrating the viability of using JJ-based control electronics located at temperature stages higher than the mixing-chamber stage in highly scaled superconducting quantum information systems.
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Affiliation(s)
- L. Howe
- National Institute of Standards and Technology, Boulder, Colorado 80305, USA
| | | | - A. J. Sirois
- National Institute of Standards and Technology, Boulder, Colorado 80305, USA
| | - D. Olaya
- National Institute of Standards and Technology, Boulder, Colorado 80305, USA
- University of Colorado, Boulder, Colorado 80309, USA
| | - J. Biesecker
- National Institute of Standards and Technology, Boulder, Colorado 80305, USA
| | - P. D. Dresselhaus
- National Institute of Standards and Technology, Boulder, Colorado 80305, USA
| | - S. P. Benz
- National Institute of Standards and Technology, Boulder, Colorado 80305, USA
| | - P. F. Hopkins
- National Institute of Standards and Technology, Boulder, Colorado 80305, USA
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