1
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Kaap F, Scheer D, Hassler F, Lotkhov S. Synchronization of Bloch Oscillations in a Strongly Coupled Pair of Small Josephson Junctions: Evidence for a Shapiro-like Current Step. PHYSICAL REVIEW LETTERS 2024; 132:027001. [PMID: 38277586 DOI: 10.1103/physrevlett.132.027001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 09/01/2023] [Accepted: 11/15/2023] [Indexed: 01/28/2024]
Abstract
Bloch oscillations are a fundamental phenomenon linking the adiabatic transport of Cooper pairs to time. Here, we investigate synchronization of the Bloch oscillations in a strongly coupled system of sub-100 nm Al/AlO_{x}/Al Josephson junctions in a high-Ohmic environment composed of highly inductive meanders of granulated aluminum and high-Ohmic titanium microstrips. We observe a pronounced current mirror effect in the coupled junctions and demonstrate current plateaus, akin to the first dual Shapiro step in microwave experiments. These findings suggest that our circuit design holds promise for realizing protected Bloch oscillations and precise Shapiro steps of interest for current metrology.
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Affiliation(s)
- Fabian Kaap
- Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany
| | - David Scheer
- JARA Institute for Quantum Information, RWTH Aachen University, 52056 Aachen, Germany
| | - Fabian Hassler
- JARA Institute for Quantum Information, RWTH Aachen University, 52056 Aachen, Germany
| | - Sergey Lotkhov
- Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany
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2
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Pishchimova AA, Smirnov NS, Ezenkova DA, Krivko EA, Zikiy EV, Moskalev DO, Ivanov AI, Korshakov ND, Rodionov IA. Improving Josephson junction reproducibility for superconducting quantum circuits: junction area fluctuation. Sci Rep 2023; 13:6772. [PMID: 37185459 PMCID: PMC10130087 DOI: 10.1038/s41598-023-34051-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 04/23/2023] [Indexed: 05/17/2023] Open
Abstract
Josephson superconducting qubits and parametric amplifiers are prominent examples of superconducting quantum circuits that have shown rapid progress in recent years. As such devices become more complex, the requirements for reproducibility of their electrical properties across a chip are being tightened. Critical current of the Josephson junction Ic is the essential electrical parameter in a chip. So, its variation is to be minimized. According to the Ambegaokar-Baratoff formula, critical current is related to normal-state resistance, which can be measured at room temperature. In this study, we focused on the dominant source of non-uniformity for the Josephson junction critical current-junction area variation. We optimized Josephson junction fabrication process and demonstrated resistance variation of 9.8-4.4% and 4.8-2.3% across 22 × 22 mm2 and 5 × 10 mm2 chip areas, respectively. For a wide range of junction areas from 0.008 to 0.12 μm2, we ensure a small linewidth standard deviation of 4 nm measured over 4500 junctions with linear dimensions from 80 to 680 nm. We found that the dominate source of junction area variation limiting [Formula: see text] reproducibility is the imperfection of the evaporation system. The developed fabrication process was tested on superconducting highly coherent transmon qubits (T1 > 100 μs) and a nonlinear asymmetric inductive element parametric amplifier.
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Affiliation(s)
- Anastasiya A Pishchimova
- FMN Laboratory, Bauman Moscow State Technical University, Moscow, 105005, Russia
- Dukhov Automatics Research Institute, VNIIA, Moscow, 127030, Russia
| | - Nikita S Smirnov
- FMN Laboratory, Bauman Moscow State Technical University, Moscow, 105005, Russia
| | - Daria A Ezenkova
- FMN Laboratory, Bauman Moscow State Technical University, Moscow, 105005, Russia
| | - Elizaveta A Krivko
- FMN Laboratory, Bauman Moscow State Technical University, Moscow, 105005, Russia
| | - Evgeniy V Zikiy
- FMN Laboratory, Bauman Moscow State Technical University, Moscow, 105005, Russia
| | - Dmitry O Moskalev
- FMN Laboratory, Bauman Moscow State Technical University, Moscow, 105005, Russia
| | - Anton I Ivanov
- FMN Laboratory, Bauman Moscow State Technical University, Moscow, 105005, Russia
| | - Nikita D Korshakov
- FMN Laboratory, Bauman Moscow State Technical University, Moscow, 105005, Russia
| | - Ilya A Rodionov
- FMN Laboratory, Bauman Moscow State Technical University, Moscow, 105005, Russia.
- Dukhov Automatics Research Institute, VNIIA, Moscow, 127030, Russia.
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3
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Yang H, Kim NY. Material-Inherent Noise Sources in Quantum Information Architecture. MATERIALS (BASEL, SWITZERLAND) 2023; 16:2561. [PMID: 37048853 PMCID: PMC10094895 DOI: 10.3390/ma16072561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/21/2022] [Revised: 10/17/2022] [Accepted: 11/22/2022] [Indexed: 06/19/2023]
Abstract
NISQ is a representative keyword at present as an acronym for "noisy intermediate-scale quantum", which identifies the current era of quantum information processing (QIP) technologies. QIP science and technologies aim to accomplish unprecedented performance in computation, communications, simulations, and sensing by exploiting the infinite capacity of parallelism, coherence, and entanglement as governing quantum mechanical principles. For the last several decades, quantum computing has reached to the technology readiness level 5, where components are integrated to build mid-sized commercial products. While this is a celebrated and triumphant achievement, we are still a great distance away from quantum-superior, fault-tolerant architecture. To reach this goal, we need to harness technologies that recognize undesirable factors to lower fidelity and induce errors from various sources of noise with controllable correction capabilities. This review surveys noisy processes arising from materials upon which several quantum architectures have been constructed, and it summarizes leading research activities in searching for origins of noise and noise reduction methods to build advanced, large-scale quantum technologies in the near future.
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Affiliation(s)
- HeeBong Yang
- Institute of Quantum Computing, University of Waterloo, 200 University Ave. West, Waterloo, ON N2L 3G1, Canada
- Department of Electrical and Computer Engineering, Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Ave. West, Waterloo, ON N2L 3G1, Canada
- Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Ave. West, Waterloo, ON N2L 3G1, Canada
| | - Na Young Kim
- Institute of Quantum Computing, University of Waterloo, 200 University Ave. West, Waterloo, ON N2L 3G1, Canada
- Department of Electrical and Computer Engineering, Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Ave. West, Waterloo, ON N2L 3G1, Canada
- Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Ave. West, Waterloo, ON N2L 3G1, Canada
- Department of Physics and Astronomy, University of Waterloo, 200 University Ave. West, Waterloo, ON N2L 3G1, Canada
- Department of Chemistry, University of Waterloo, 200 University Ave. West, Waterloo, ON N2L 3G1, Canada
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4
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Maillard D, Benes Z, Piacentini N, Villanueva LG. Electron-beam lithography on M108Y and M35G chemically amplified DUV photoresists. MICRO AND NANO ENGINEERING 2021. [DOI: 10.1016/j.mne.2021.100095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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5
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Wang Z, Xu M, Han X, Fu W, Puri S, Girvin SM, Tang HX, Shankar S, Devoret MH. Quantum Microwave Radiometry with a Superconducting Qubit. PHYSICAL REVIEW LETTERS 2021; 126:180501. [PMID: 34018799 DOI: 10.1103/physrevlett.126.180501] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2019] [Accepted: 03/29/2021] [Indexed: 06/12/2023]
Abstract
The interaction of photons and coherent quantum systems can be employed to detect electromagnetic radiation with remarkable sensitivity. We introduce a quantum radiometer based on the photon-induced dephasing process of a superconducting qubit for sensing microwave radiation at the subunit photon level. Using this radiometer, we demonstrate the radiative cooling of a 1 K microwave resonator and measure its mode temperature with an uncertainty ∼0.01 K. We thus develop a precise tool for studying the thermodynamics of quantum microwave circuits, which provides new solutions for calibrating hybrid quantum systems and detecting candidate particles for dark matter.
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Affiliation(s)
- Zhixin Wang
- Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - Mingrui Xu
- Department of Electrical Engineering, Yale University, New Haven, Connecticut 06520, USA
| | - Xu Han
- Department of Electrical Engineering, Yale University, New Haven, Connecticut 06520, USA
| | - Wei Fu
- Department of Electrical Engineering, Yale University, New Haven, Connecticut 06520, USA
| | - Shruti Puri
- Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - S M Girvin
- Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - Hong X Tang
- Department of Electrical Engineering, Yale University, New Haven, Connecticut 06520, USA
| | - S Shankar
- Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - M H Devoret
- Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
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6
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Chen L, Sun L, Dong H, Mou N, Zhang Y, Li Q, Jiang X, Zhang L. Near-field imaging of the multi-resonant mode induced broadband tunable metamaterial absorber. RSC Adv 2020; 10:5146-5151. [PMID: 35498277 PMCID: PMC9049137 DOI: 10.1039/c9ra10233g] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 12/28/2019] [Indexed: 12/30/2022] Open
Abstract
Metamaterial absorbers with tunability have broad prospects for mid-infrared absorption applications. While various methods have been proposed to control absorption, how to analyse and present the physical image of absorption mechanism in depth is still expected and meaningful. Here, we present experimental spatial near-field distributions of a multi-resonant mode induced broadband tunable metamaterial absorber by using near-field optical microscopy. The absorber is constructed by a metal double-sized unit cell and a metallic mirror separated by a thin Ge2Sb2Te5 (GST) spacer. To clearly obtain the physical images, we used a hybrid unit cell consisting of four square resonators to produce two absorption peaks at 7.8 μm and 8.3 μm. The resonance central-wavelength exhibits a redshift while switching the GST thin film from amorphous to crystalline phase. The near-field amplitude and phase optical responses of the absorber are directly observed at absorption frequencies when GST is in both phases, respectively. This work will pave the way for the fundamental science field and inspire potential applications in optical tunable absorption control. Metamaterial absorbers with tunability have broad prospects for mid-infrared absorption applications.![]()
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Affiliation(s)
- Lulu Chen
- Key Laboratory of Materials for High-Power Laser, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences Shanghai 201800 China .,Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences Beijing 100049 China
| | - Liaoxin Sun
- National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences Shanghai 200083 China
| | - Hongxing Dong
- Key Laboratory of Materials for High-Power Laser, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences Shanghai 201800 China
| | - Nanli Mou
- Key Laboratory of Materials for High-Power Laser, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences Shanghai 201800 China .,Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences Beijing 100049 China
| | - Yaqiang Zhang
- Key Laboratory of Materials for High-Power Laser, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences Shanghai 201800 China .,Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences Beijing 100049 China
| | - Qisong Li
- Key Laboratory of Materials for High-Power Laser, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences Shanghai 201800 China
| | - Xiongwei Jiang
- Key Laboratory of Materials for High-Power Laser, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences Shanghai 201800 China
| | - Long Zhang
- Key Laboratory of Materials for High-Power Laser, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences Shanghai 201800 China
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7
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Grünhaupt L, Spiecker M, Gusenkova D, Maleeva N, Skacel ST, Takmakov I, Valenti F, Winkel P, Rotzinger H, Wernsdorfer W, Ustinov AV, Pop IM. Granular aluminium as a superconducting material for high-impedance quantum circuits. NATURE MATERIALS 2019; 18:816-819. [PMID: 31036961 DOI: 10.1038/s41563-019-0350-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 03/18/2019] [Indexed: 06/09/2023]
Abstract
Superconducting quantum information processing machines are predominantly based on microwave circuits with relatively low characteristic impedance, about 100 Ω, and small anharmonicity, which can limit their coherence and logic gate fidelity1,2. A promising alternative is circuits based on so-called superinductors3-6, with characteristic impedances exceeding the resistance quantum RQ = 6.4 kΩ. However, previous implementations of superinductors, consisting of mesoscopic Josephson junction arrays7,8, can introduce unintended nonlinearity or parasitic resonant modes in the qubit vicinity, degrading its coherence. Here, we present a fluxonium qubit design based on a granular aluminium superinductor strip9-11. We show that granular aluminium can form an effective junction array with high kinetic inductance and be in situ integrated with standard aluminium circuit processing. The measured qubit coherence time [Formula: see text] illustrates the potential of granular aluminium for applications ranging from protected qubit designs to quantum-limited amplifiers and detectors.
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Affiliation(s)
- Lukas Grünhaupt
- Physikalisches Institut, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Martin Spiecker
- Physikalisches Institut, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Daria Gusenkova
- Physikalisches Institut, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Nataliya Maleeva
- Physikalisches Institut, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Sebastian T Skacel
- Physikalisches Institut, Karlsruhe Institute of Technology, Karlsruhe, Germany
- Institute of Nanotechnology, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
| | - Ivan Takmakov
- Physikalisches Institut, Karlsruhe Institute of Technology, Karlsruhe, Germany
- Institute of Nanotechnology, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
- Russian Quantum Center, National University of Science and Technology MISIS, Moscow, Russia
| | - Francesco Valenti
- Physikalisches Institut, Karlsruhe Institute of Technology, Karlsruhe, Germany
- Institute for Data Processing and Electronics, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
| | - Patrick Winkel
- Physikalisches Institut, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Hannes Rotzinger
- Physikalisches Institut, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Wolfgang Wernsdorfer
- Physikalisches Institut, Karlsruhe Institute of Technology, Karlsruhe, Germany
- Institute of Nanotechnology, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
| | - Alexey V Ustinov
- Physikalisches Institut, Karlsruhe Institute of Technology, Karlsruhe, Germany
- Russian Quantum Center, National University of Science and Technology MISIS, Moscow, Russia
| | - Ioan M Pop
- Physikalisches Institut, Karlsruhe Institute of Technology, Karlsruhe, Germany.
- Institute of Nanotechnology, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany.
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8
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To catch and reverse a quantum jump mid-flight. Nature 2019; 570:200-204. [DOI: 10.1038/s41586-019-1287-z] [Citation(s) in RCA: 132] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 04/04/2019] [Indexed: 11/08/2022]
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9
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Serniak K, Hays M, de Lange G, Diamond S, Shankar S, Burkhart LD, Frunzio L, Houzet M, Devoret MH. Hot Nonequilibrium Quasiparticles in Transmon Qubits. PHYSICAL REVIEW LETTERS 2018; 121:157701. [PMID: 30362798 DOI: 10.1103/physrevlett.121.157701] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Revised: 07/27/2018] [Indexed: 06/08/2023]
Abstract
Nonequilibrium quasiparticle excitations degrade the performance of a variety of superconducting circuits. Understanding the energy distribution of these quasiparticles will yield insight into their generation mechanisms, the limitations they impose on superconducting devices, and how to efficiently mitigate quasiparticle-induced qubit decoherence. To probe this energy distribution, we systematically correlate qubit relaxation and excitation with charge-parity switches in an offset-charge-sensitive transmon qubit, and find that quasiparticle-induced excitation events are the dominant mechanism behind the residual excited-state population in our samples. By itself, the observed quasiparticle distribution would limit T_{1} to ≈200 μs, which indicates that quasiparticle loss in our devices is on equal footing with all other loss mechanisms. Furthermore, the measured rate of quasiparticle-induced excitation events is greater than that of relaxation events, which signifies that the quasiparticles are more energetic than would be predicted from a thermal distribution describing their apparent density.
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Affiliation(s)
- K Serniak
- Department of Applied Physics, Yale University, New Haven, Connecticut 06520, USA
| | - M Hays
- Department of Applied Physics, Yale University, New Haven, Connecticut 06520, USA
| | - G de Lange
- Department of Applied Physics, Yale University, New Haven, Connecticut 06520, USA
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, 2600 GA Delft, Netherlands
| | - S Diamond
- Department of Applied Physics, Yale University, New Haven, Connecticut 06520, USA
| | - S Shankar
- Department of Applied Physics, Yale University, New Haven, Connecticut 06520, USA
| | - L D Burkhart
- Department of Applied Physics, Yale University, New Haven, Connecticut 06520, USA
| | - L Frunzio
- Department of Applied Physics, Yale University, New Haven, Connecticut 06520, USA
| | - M Houzet
- Univ. Grenoble Alpes, CEA, INAC-Pheliqs, F-38000 Grenoble, France
| | - M H Devoret
- Department of Applied Physics, Yale University, New Haven, Connecticut 06520, USA
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10
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Earnest N, Chakram S, Lu Y, Irons N, Naik RK, Leung N, Ocola L, Czaplewski DA, Baker B, Lawrence J, Koch J, Schuster DI. Realization of a Λ System with Metastable States of a Capacitively Shunted Fluxonium. PHYSICAL REVIEW LETTERS 2018; 120:150504. [PMID: 29756860 DOI: 10.1103/physrevlett.120.150504] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Indexed: 06/08/2023]
Abstract
We realize a Λ system in a superconducting circuit, with metastable states exhibiting lifetimes up to 8 ms. We exponentially suppress the tunneling matrix elements involved in spontaneous energy relaxation by creating a "heavy" fluxonium, realized by adding a capacitive shunt to the original circuit design. The device allows for both cavity-assisted and direct fluorescent readouts, as well as state preparation schemes akin to optical pumping. Since direct transitions between the metastable states are strongly suppressed, we utilize Raman transitions for coherent manipulation of the states.
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Affiliation(s)
- N Earnest
- The James Franck Institute and Department of Physics, University of Chicago, Chicago, Illinois 60637, USA
| | - S Chakram
- The James Franck Institute and Department of Physics, University of Chicago, Chicago, Illinois 60637, USA
| | - Y Lu
- The James Franck Institute and Department of Physics, University of Chicago, Chicago, Illinois 60637, USA
| | - N Irons
- Department of Physics and Astronomy, Northwestern University, Evanston, Illinois 60208, USA
| | - R K Naik
- The James Franck Institute and Department of Physics, University of Chicago, Chicago, Illinois 60637, USA
| | - N Leung
- The James Franck Institute and Department of Physics, University of Chicago, Chicago, Illinois 60637, USA
| | - L Ocola
- Argonne National Laboratories, Center for Nanoscale Materials, Argonne, Illinois 60439, USA
| | - D A Czaplewski
- Argonne National Laboratories, Center for Nanoscale Materials, Argonne, Illinois 60439, USA
| | - B Baker
- Department of Physics and Astronomy, Northwestern University, Evanston, Illinois 60208, USA
| | - Jay Lawrence
- Department of Physics, Dartmouth College, Hanover, New Hampshire 03755, USA
| | - Jens Koch
- Department of Physics and Astronomy, Northwestern University, Evanston, Illinois 60208, USA
| | - D I Schuster
- The James Franck Institute and Department of Physics, University of Chicago, Chicago, Illinois 60637, USA
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11
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DuBois T, Cyster M, Opletal G, Russo S, Cole J. Constructingab initiomodels of ultra-thin Al–AlOx–Al barriers. MOLECULAR SIMULATION 2015. [DOI: 10.1080/08927022.2015.1068941] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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12
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Leghtas Z, Touzard S, Pop IM, Kou A, Vlastakis B, Petrenko A, Sliwa KM, Narla A, Shankar S, Hatridge MJ, Reagor M, Frunzio L, Schoelkopf RJ, Mirrahimi M, Devoret MH. Confining the state of light to a quantum manifold by engineered two-photon loss. Science 2015; 347:853-7. [DOI: 10.1126/science.aaa2085] [Citation(s) in RCA: 262] [Impact Index Per Article: 29.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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13
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Vool U, Pop IM, Sliwa K, Abdo B, Wang C, Brecht T, Gao YY, Shankar S, Hatridge M, Catelani G, Mirrahimi M, Frunzio L, Schoelkopf RJ, Glazman LI, Devoret MH. Non-Poissonian quantum jumps of a fluxonium qubit due to quasiparticle excitations. PHYSICAL REVIEW LETTERS 2014; 113:247001. [PMID: 25541795 DOI: 10.1103/physrevlett.113.247001] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Indexed: 06/04/2023]
Abstract
As the energy relaxation time of superconducting qubits steadily improves, nonequilibrium quasiparticle excitations above the superconducting gap emerge as an increasingly relevant limit for qubit coherence. We measure fluctuations in the number of quasiparticle excitations by continuously monitoring the spontaneous quantum jumps between the states of a fluxonium qubit, in conditions where relaxation is dominated by quasiparticle loss. Resolution on the scale of a single quasiparticle is obtained by performing quantum nondemolition projective measurements within a time interval much shorter than T₁, using a quantum-limited amplifier (Josephson parametric converter). The quantum jump statistics switches between the expected Poisson distribution and a non-Poissonian one, indicating large relative fluctuations in the quasiparticle population, on time scales varying from seconds to hours. This dynamics can be modified controllably by injecting quasiparticles or by seeding quasiparticle-trapping vortices by cooling down in a magnetic field.
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Affiliation(s)
- U Vool
- Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - I M Pop
- Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - K Sliwa
- Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - B Abdo
- Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - C Wang
- Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - T Brecht
- Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - Y Y Gao
- Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - S Shankar
- Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - M Hatridge
- Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - G Catelani
- Peter Grünberg Institut (PGI-2), Forschungszentrum Jülich, 52425 Jülich, Germany
| | - M Mirrahimi
- Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA and INRIA Paris-Rocquencourt, Domaine de Voluceau, BP105, 78153 Le Chesnay cedex, France
| | - L Frunzio
- Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - R J Schoelkopf
- Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - L I Glazman
- Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - M H Devoret
- Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
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14
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Eichler C, Salathe Y, Mlynek J, Schmidt S, Wallraff A. Quantum-limited amplification and entanglement in coupled nonlinear resonators. PHYSICAL REVIEW LETTERS 2014; 113:110502. [PMID: 25259964 DOI: 10.1103/physrevlett.113.110502] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Indexed: 06/03/2023]
Abstract
We demonstrate a coupled cavity realization of a Bose-Hubbard dimer to achieve quantum-limited amplification and to generate frequency entangled microwave fields with squeezing parameters well below -12 dB. In contrast to previous implementations of parametric amplifiers, our dimer can be operated both as a degenerate and as a nondegenerate amplifier. The large measured gain-bandwidth product of more than 250 MHz for the nondegenerate operation and the saturation at input photon numbers as high as 2000 per μs are both expected to be improvable even further, while maintaining wide frequency tunability of about 2 GHz. Featuring flexible control over all relevant system parameters, the presented Bose-Hubbard dimer based on lumped element circuits has significant potential as an elementary cell in nonlinear cavity arrays for quantum simulations.
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Affiliation(s)
- C Eichler
- Department of Physics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - Y Salathe
- Department of Physics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - J Mlynek
- Department of Physics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - S Schmidt
- Institute for Theoretical Physics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - A Wallraff
- Department of Physics, ETH Zürich, CH-8093 Zürich, Switzerland
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15
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Pop IM, Geerlings K, Catelani G, Schoelkopf RJ, Glazman LI, Devoret MH. Coherent suppression of electromagnetic dissipation due to superconducting quasiparticles. Nature 2014; 508:369-72. [DOI: 10.1038/nature13017] [Citation(s) in RCA: 161] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Accepted: 01/13/2014] [Indexed: 11/09/2022]
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16
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Shankar S, Hatridge M, Leghtas Z, Sliwa KM, Narla A, Vool U, Girvin SM, Frunzio L, Mirrahimi M, Devoret MH. Autonomously stabilized entanglement between two superconducting quantum bits. Nature 2013; 504:419-22. [PMID: 24270808 DOI: 10.1038/nature12802] [Citation(s) in RCA: 234] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Accepted: 10/22/2013] [Indexed: 12/27/2022]
Abstract
Quantum error correction codes are designed to protect an arbitrary state of a multi-qubit register from decoherence-induced errors, but their implementation is an outstanding challenge in the development of large-scale quantum computers. The first step is to stabilize a non-equilibrium state of a simple quantum system, such as a quantum bit (qubit) or a cavity mode, in the presence of decoherence. This has recently been accomplished using measurement-based feedback schemes. The next step is to prepare and stabilize a state of a composite system. Here we demonstrate the stabilization of an entangled Bell state of a quantum register of two superconducting qubits for an arbitrary time. Our result is achieved using an autonomous feedback scheme that combines continuous drives along with a specifically engineered coupling between the two-qubit register and a dissipative reservoir. Similar autonomous feedback techniques have been used for qubit reset, single-qubit state stabilization, and the creation and stabilization of states of multipartite quantum systems. Unlike conventional, measurement-based schemes, the autonomous approach uses engineered dissipation to counteract decoherence, obviating the need for a complicated external feedback loop to correct errors. Instead, the feedback loop is built into the Hamiltonian such that the steady state of the system in the presence of drives and dissipation is a Bell state, an essential building block for quantum information processing. Such autonomous schemes, which are broadly applicable to a variety of physical systems, as demonstrated by the accompanying paper on trapped ion qubits, will be an essential tool for the implementation of quantum error correction.
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Affiliation(s)
- S Shankar
- Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - M Hatridge
- Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - Z Leghtas
- Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - K M Sliwa
- Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - A Narla
- Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - U Vool
- Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - S M Girvin
- Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - L Frunzio
- Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - M Mirrahimi
- 1] Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA [2] INRIA Paris-Rocquencourt, Domaine de Voluceau, BP 105, 78153 Le Chesnay Cedex, France
| | - M H Devoret
- Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
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Geerlings K, Leghtas Z, Pop IM, Shankar S, Frunzio L, Schoelkopf RJ, Mirrahimi M, Devoret MH. Demonstrating a driven reset protocol for a superconducting qubit. PHYSICAL REVIEW LETTERS 2013; 110:120501. [PMID: 25166782 DOI: 10.1103/physrevlett.110.120501] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Indexed: 06/03/2023]
Abstract
Qubit reset is crucial at the start of and during quantum information algorithms. We present the experimental demonstration of a practical method to force qubits into their ground state, based on driving appropriate qubit and cavity transitions. Our protocol, called the double drive reset of population, is tested on a superconducting transmon qubit in a three-dimensional cavity. Using a new method for measuring population, we show that we can prepare the ground state with a fidelity of at least 99.5% in less than 3 μs; faster times and higher fidelity are predicted upon parameter optimization.
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Affiliation(s)
- K Geerlings
- Department of Applied Physics, Yale University, New Haven, Connecticut 06520-8284, USA
| | - Z Leghtas
- INRIA Paris-Rocquencourt, Domaine de Voluceau, B.P. 105, 78153 Le Chesnay cedex, France
| | - I M Pop
- Department of Applied Physics, Yale University, New Haven, Connecticut 06520-8284, USA
| | - S Shankar
- Department of Applied Physics, Yale University, New Haven, Connecticut 06520-8284, USA
| | - L Frunzio
- Department of Applied Physics, Yale University, New Haven, Connecticut 06520-8284, USA
| | - R J Schoelkopf
- Department of Applied Physics, Yale University, New Haven, Connecticut 06520-8284, USA
| | - M Mirrahimi
- Department of Applied Physics, Yale University, New Haven, Connecticut 06520-8284, USA and INRIA Paris-Rocquencourt, Domaine de Voluceau, B.P. 105, 78153 Le Chesnay cedex, France
| | - M H Devoret
- Department of Applied Physics, Yale University, New Haven, Connecticut 06520-8284, USA
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18
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Masluk NA, Pop IM, Kamal A, Minev ZK, Devoret MH. Microwave characterization of Josephson junction arrays: implementing a low loss superinductance. PHYSICAL REVIEW LETTERS 2012; 109:137002. [PMID: 23030112 DOI: 10.1103/physrevlett.109.137002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2012] [Indexed: 06/01/2023]
Abstract
We have measured the plasma resonances of an array of Josephson junctions in the regime E(J)>>E(C), up to the ninth harmonic by incorporating it as part of a resonator capacitively coupled to a coplanar waveguide. From the characteristics of the resonances, we infer the successful implementation of a superinductance, an electrical element with a nondissipative impedance greater than the resistance quantum [R(Q)=h/(2e)(2) is approximately equal to 6.5 kΩ] at microwave frequencies. Such an element is crucial for preserving the quantum coherence in circuits exploiting large fluctuations of the superconducting phase. Our results show internal losses less than 20 ppm, self-resonant frequencies greater than 10 GHz, and phase-slip rates less than 1 mHz, enabling direct application of such arrays for quantum information and metrology. Arrays with a loop geometry also demonstrate a new manifestation of flux quantization in a dispersive analog of the Little-Parks effect.
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Affiliation(s)
- Nicholas A Masluk
- Department of Applied Physics, Yale University, New Haven, Connecticut 06511, USA.
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19
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Lecocq F, Pop IM, Matei I, Dumur E, Feofanov AK, Naud C, Guichard W, Buisson O. Coherent frequency conversion in a superconducting artificial atom with two internal degrees of freedom. PHYSICAL REVIEW LETTERS 2012; 108:107001. [PMID: 22463441 DOI: 10.1103/physrevlett.108.107001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2011] [Indexed: 05/31/2023]
Abstract
By adding a large inductance in a dc-SQUID phase qubit loop, one decouples the junctions' dynamics and creates a superconducting artificial atom with two internal degrees of freedom. In addition to the usual symmetric plasma mode (s mode) which gives rise to the phase qubit, an antisymmetric mode (a mode) appears. These two modes can be described by two anharmonic oscillators with eigenstates |ns> and |na> for the s and a mode, respectively. We show that a strong nonlinear coupling between the modes leads to a large energy splitting between states |0s,1a> and |2s,0a>. Finally, coherent frequency conversion is observed via free oscillations between the states |0s,1a> and |2s,0a>.
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Affiliation(s)
- F Lecocq
- Institut Néel, CNRS-Université Joseph Fourier, BP 166, 38042 Grenoble-cedex 9, France
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