1
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Qiao H, Dumur É, Andersson G, Yan H, Chou MH, Grebel J, Conner CR, Joshi YJ, Miller JM, Povey RG, Wu X, Cleland AN. Splitting phonons: Building a platform for linear mechanical quantum computing. Science 2023; 380:1030-1033. [PMID: 37289889 DOI: 10.1126/science.adg8715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Accepted: 04/28/2023] [Indexed: 06/10/2023]
Abstract
Linear optical quantum computing provides a desirable approach to quantum computing, with only a short list of required computational elements. The similarity between photons and phonons points to the interesting potential for linear mechanical quantum computing using phonons in place of photons. Although single-phonon sources and detectors have been demonstrated, a phononic beam splitter element remains an outstanding requirement. Here we demonstrate such an element, using two superconducting qubits to fully characterize a beam splitter with single phonons. We further use the beam splitter to demonstrate two-phonon interference, a requirement for two-qubit gates in linear computing. This advances a new solid-state system for implementing linear quantum computing, further providing straightforward conversion between itinerant phonons and superconducting qubits.
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Affiliation(s)
- H Qiao
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
| | - É Dumur
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
- Center for Molecular Engineering and Material Science Division, Argonne National Laboratory, Lemont, IL 60439, USA
| | - G Andersson
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
| | - H Yan
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
| | - M-H Chou
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
- Department of Physics, University of Chicago, Chicago, IL 60637, USA
| | - J Grebel
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
| | - C R Conner
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
| | - Y J Joshi
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
| | - J M Miller
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
- Department of Physics, University of Chicago, Chicago, IL 60637, USA
| | - R G Povey
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
- Department of Physics, University of Chicago, Chicago, IL 60637, USA
| | - X Wu
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
| | - A N Cleland
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
- Center for Molecular Engineering and Material Science Division, Argonne National Laboratory, Lemont, IL 60439, USA
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2
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Chang HS, Zhong YP, Bienfait A, Chou MH, Conner CR, Dumur É, Grebel J, Peairs GA, Povey RG, Satzinger KJ, Cleland AN. Remote Entanglement via Adiabatic Passage Using a Tunably Dissipative Quantum Communication System. Phys Rev Lett 2020; 124:240502. [PMID: 32639797 DOI: 10.1103/physrevlett.124.240502] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 05/18/2020] [Indexed: 06/11/2023]
Abstract
Effective quantum communication between remote quantum nodes requires high fidelity quantum state transfer and remote entanglement generation. Recent experiments have demonstrated that microwave photons, as well as phonons, can be used to couple superconducting qubits, with a fidelity limited primarily by loss in the communication channel [P. Kurpiers et al., Nature (London) 558, 264 (2018)NATUAS0028-083610.1038/s41586-018-0195-y; C. J. Axline et al., Nat. Phys. 14, 705 (2018)NPAHAX1745-247310.1038/s41567-018-0115-y; P. Campagne-Ibarcq et al., Phys. Rev. Lett. 120, 200501 (2018)PRLTAO0031-900710.1103/PhysRevLett.120.200501; N. Leung et al., npj Quantum Inf. 5, 18 (2019)2056-638710.1038/s41534-019-0128-0; Y. P. Zhong et al., Nat. Phys. 15, 741 (2019)NPAHAX1745-247310.1038/s41567-019-0507-7; A. Bienfait et al., Science 364, 368 (2019)SCIEAS0036-807510.1126/science.aaw8415]. Adiabatic protocols can overcome channel loss by transferring quantum states without populating the lossy communication channel. Here, we present a unique superconducting quantum communication system, comprising two superconducting qubits connected by a 0.73 m-long communication channel. Significantly, we can introduce large tunable loss to the channel, allowing exploration of different entanglement protocols in the presence of dissipation. When set for minimum loss in the channel, we demonstrate an adiabatic quantum state transfer protocol that achieves 99% transfer efficiency as well as the deterministic generation of entangled Bell states with a fidelity of 96%, all without populating the intervening communication channel, and competitive with a qubit-resonant mode-qubit relay method. We also explore the performance of the adiabatic protocol in the presence of significant channel loss, and show that the adiabatic protocol protects against loss in the channel, achieving higher state transfer and entanglement fidelities than the relay method.
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Affiliation(s)
- H-S Chang
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, USA
| | - Y P Zhong
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, USA
| | - A Bienfait
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, USA
| | - M-H Chou
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, USA
- Department of Physics, University of Chicago, Chicago, Illinois 60637, USA
| | - C R Conner
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, USA
| | - É Dumur
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, USA
- Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - J Grebel
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, USA
| | - G A Peairs
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, USA
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - R G Povey
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, USA
- Department of Physics, University of Chicago, Chicago, Illinois 60637, USA
| | - K J Satzinger
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, USA
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - A N Cleland
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, USA
- Argonne National Laboratory, Argonne, Illinois 60439, USA
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3
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Bienfait A, Satzinger KJ, Zhong YP, Chang HS, Chou MH, Conner CR, Dumur É, Grebel J, Peairs GA, Povey RG, Cleland AN. Phonon-mediated quantum state transfer and remote qubit entanglement. Science 2019; 364:368-371. [PMID: 31023919 DOI: 10.1126/science.aaw8415] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 03/25/2019] [Indexed: 01/03/2023]
Abstract
Phonons, and in particular surface acoustic wave phonons, have been proposed as a means to coherently couple distant solid-state quantum systems. Individual phonons in a resonant structure can be controlled and detected by superconducting qubits, enabling the coherent generation and measurement of complex stationary phonon states. We report the deterministic emission and capture of itinerant surface acoustic wave phonons, enabling the quantum entanglement of two superconducting qubits. Using a 2-millimeter-long acoustic quantum communication channel, equivalent to a 500-nanosecond delay line, we demonstrate the emission and recapture of a phonon by one superconducting qubit, quantum state transfer between two superconducting qubits with a 67% efficiency, and, by partial transfer of a phonon, generation of an entangled Bell pair with a fidelity of 84%.
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Affiliation(s)
- A Bienfait
- Institute for Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
| | - K J Satzinger
- Department of Physics, University of California, Santa Barbara, Santa Barbara, CA 93106, USA.,Institute for Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
| | - Y P Zhong
- Institute for Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
| | - H-S Chang
- Institute for Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
| | - M-H Chou
- Institute for Molecular Engineering, University of Chicago, Chicago, IL 60637, USA.,Department of Physics, University of Chicago, Chicago, IL 60637, USA
| | - C R Conner
- Institute for Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
| | - É Dumur
- Institute for Molecular Engineering, University of Chicago, Chicago, IL 60637, USA.,Institute for Molecular Engineering and Materials Science Division, Argonne National Laboratory, Argonne, IL 60439, USA
| | - J Grebel
- Institute for Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
| | - G A Peairs
- Department of Physics, University of California, Santa Barbara, Santa Barbara, CA 93106, USA.,Institute for Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
| | - R G Povey
- Institute for Molecular Engineering, University of Chicago, Chicago, IL 60637, USA.,Department of Physics, University of Chicago, Chicago, IL 60637, USA
| | - A N Cleland
- Institute for Molecular Engineering, University of Chicago, Chicago, IL 60637, USA. .,Institute for Molecular Engineering and Materials Science Division, Argonne National Laboratory, Argonne, IL 60439, USA
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4
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Zheng SB, Zhong YP, Xu K, Wang QJ, Wang H, Shen LT, Yang CP, Martinis JM, Cleland AN, Han SY. Quantum Delayed-Choice Experiment with a Beam Splitter in a Quantum Superposition. Phys Rev Lett 2015; 115:260403. [PMID: 26764976 DOI: 10.1103/physrevlett.115.260403] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Indexed: 06/05/2023]
Abstract
A quantum system can behave as a wave or as a particle, depending on the experimental arrangement. When, for example, measuring a photon using a Mach-Zehnder interferometer, the photon acts as a wave if the second beam splitter is inserted, but as a particle if this beam splitter is omitted. The decision of whether or not to insert this beam splitter can be made after the photon has entered the interferometer, as in Wheeler's famous delayed-choice thought experiment. In recent quantum versions of this experiment, this decision is controlled by a quantum ancilla, while the beam splitter is itself still a classical object. Here, we propose and realize a variant of the quantum delayed-choice experiment. We configure a superconducting quantum circuit as a Ramsey interferometer, where the element that acts as the first beam splitter can be put in a quantum superposition of its active and inactive states, as verified by the negative values of its Wigner function. We show that this enables the wave and particle aspects of the system to be observed with a single setup, without involving an ancilla that is not itself a part of the interferometer. We also study the transition of this quantum beam splitter from a quantum to a classical object due to decoherence, as observed by monitoring the interferometer output.
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Affiliation(s)
- Shi-Biao Zheng
- Department of Physics, Fuzhou University, Fuzhou 350116, China
| | - You-Peng Zhong
- Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Kai Xu
- Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Qi-Jue Wang
- Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - H Wang
- Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Li-Tuo Shen
- Department of Physics, Fuzhou University, Fuzhou 350116, China
| | - Chui-Ping Yang
- Department of Physics, Hangzhou Normal University, Hangzhou 310036, China
| | - John M Martinis
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - A N Cleland
- Institute for Molecular Engineering, University of Chicago, Chicago, Illinois 60637, USA
| | - Si-Yuan Han
- Department of Physics and Astronomy, University of Kansas, Lawrence, Kansas 66045, USA
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
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5
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Kelly J, Barends R, Fowler AG, Megrant A, Jeffrey E, White TC, Sank D, Mutus JY, Campbell B, Chen Y, Chen Z, Chiaro B, Dunsworth A, Hoi IC, Neill C, O'Malley PJJ, Quintana C, Roushan P, Vainsencher A, Wenner J, Cleland AN, Martinis JM. State preservation by repetitive error detection in a superconducting quantum circuit. Nature 2015; 519:66-9. [PMID: 25739628 DOI: 10.1038/nature14270] [Citation(s) in RCA: 130] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2014] [Accepted: 01/27/2015] [Indexed: 12/19/2022]
Abstract
Quantum computing becomes viable when a quantum state can be protected from environment-induced error. If quantum bits (qubits) are sufficiently reliable, errors are sparse and quantum error correction (QEC) is capable of identifying and correcting them. Adding more qubits improves the preservation of states by guaranteeing that increasingly larger clusters of errors will not cause logical failure-a key requirement for large-scale systems. Using QEC to extend the qubit lifetime remains one of the outstanding experimental challenges in quantum computing. Here we report the protection of classical states from environmental bit-flip errors and demonstrate the suppression of these errors with increasing system size. We use a linear array of nine qubits, which is a natural step towards the two-dimensional surface code QEC scheme, and track errors as they occur by repeatedly performing projective quantum non-demolition parity measurements. Relative to a single physical qubit, we reduce the failure rate in retrieving an input state by a factor of 2.7 when using five of our nine qubits and by a factor of 8.5 when using all nine qubits after eight cycles. Additionally, we tomographically verify preservation of the non-classical Greenberger-Horne-Zeilinger state. The successful suppression of environment-induced errors will motivate further research into the many challenges associated with building a large-scale superconducting quantum computer.
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Affiliation(s)
- J Kelly
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - R Barends
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - A G Fowler
- 1] Department of Physics, University of California, Santa Barbara, California 93106, USA [2] Centre for Quantum Computation and Communication Technology, School of Physics, The University of Melbourne, Victoria 3010, Australia
| | - A Megrant
- 1] Department of Physics, University of California, Santa Barbara, California 93106, USA [2] Department of Materials, University of California, Santa Barbara, California 93106, USA
| | - E Jeffrey
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - T C White
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - D Sank
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - J Y Mutus
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - B Campbell
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - Yu Chen
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - Z Chen
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - B Chiaro
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - A Dunsworth
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - I-C Hoi
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - C Neill
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - P J J O'Malley
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - C Quintana
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - P Roushan
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - A Vainsencher
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - J Wenner
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - A N Cleland
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - John M Martinis
- Department of Physics, University of California, Santa Barbara, California 93106, USA
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6
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Chen Y, Neill C, Roushan P, Leung N, Fang M, Barends R, Kelly J, Campbell B, Chen Z, Chiaro B, Dunsworth A, Jeffrey E, Megrant A, Mutus JY, O'Malley PJJ, Quintana CM, Sank D, Vainsencher A, Wenner J, White TC, Geller MR, Cleland AN, Martinis JM. Qubit Architecture with High Coherence and Fast Tunable Coupling. Phys Rev Lett 2014; 113:220502. [PMID: 25494061 DOI: 10.1103/physrevlett.113.220502] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Indexed: 06/04/2023]
Abstract
We introduce a superconducting qubit architecture that combines high-coherence qubits and tunable qubit-qubit coupling. With the ability to set the coupling to zero, we demonstrate that this architecture is protected from the frequency crowding problems that arise from fixed coupling. More importantly, the coupling can be tuned dynamically with nanosecond resolution, making this architecture a versatile platform with applications ranging from quantum logic gates to quantum simulation. We illustrate the advantages of dynamical coupling by implementing a novel adiabatic controlled-z gate, with a speed approaching that of single-qubit gates. Integrating coherence and scalable control, the introduced qubit architecture provides a promising path towards large-scale quantum computation and simulation.
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Affiliation(s)
- Yu Chen
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
| | - C Neill
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
| | - P Roushan
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
| | - N Leung
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
| | - M Fang
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
| | - R Barends
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
| | - J Kelly
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
| | - B Campbell
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
| | - Z Chen
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
| | - B Chiaro
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
| | - A Dunsworth
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
| | - E Jeffrey
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
| | - A Megrant
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA and Department of Materials, University of California, Santa Barbara, California 93106-5050, USA
| | - J Y Mutus
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
| | - P J J O'Malley
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
| | - C M Quintana
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
| | - D Sank
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
| | - A Vainsencher
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
| | - J Wenner
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
| | - T C White
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
| | - Michael R Geller
- Department of Physics and Astronomy, University of Georgia, Athens, Georgia 30602, USA
| | - A N Cleland
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
| | - John M Martinis
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
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7
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Roushan P, Neill C, Chen Y, Kolodrubetz M, Quintana C, Leung N, Fang M, Barends R, Campbell B, Chen Z, Chiaro B, Dunsworth A, Jeffrey E, Kelly J, Megrant A, Mutus J, O’Malley PJJ, Sank D, Vainsencher A, Wenner J, White T, Polkovnikov A, Cleland AN, Martinis JM. Observation of topological transitions in interacting quantum circuits. Nature 2014; 515:241-4. [DOI: 10.1038/nature13891] [Citation(s) in RCA: 145] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Accepted: 09/23/2014] [Indexed: 11/09/2022]
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8
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Kelly J, Barends R, Campbell B, Chen Y, Chen Z, Chiaro B, Dunsworth A, Fowler AG, Hoi IC, Jeffrey E, Megrant A, Mutus J, Neill C, O'Malley PJJ, Quintana C, Roushan P, Sank D, Vainsencher A, Wenner J, White TC, Cleland AN, Martinis JM. Optimal quantum control using randomized benchmarking. Phys Rev Lett 2014; 112:240504. [PMID: 24996075 DOI: 10.1103/physrevlett.112.240504] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Indexed: 06/03/2023]
Abstract
We present a method for optimizing quantum control in experimental systems, using a subset of randomized benchmarking measurements to rapidly infer error. This is demonstrated to improve single- and two-qubit gates, minimize gate bleedthrough, where a gate mechanism can cause errors on subsequent gates, and identify control crosstalk in superconducting qubits. This method is able to correct parameters so that control errors no longer dominate and is suitable for automated and closed-loop optimization of experimental systems.
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Affiliation(s)
- J Kelly
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - R Barends
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - B Campbell
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - Y Chen
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - Z Chen
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - B Chiaro
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - A Dunsworth
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - A G Fowler
- Department of Physics, University of California, Santa Barbara, California 93106, USA and Centre for Quantum Computation and Communication Technology, School of Physics, The University of Melbourne, Victoria 3010, Australia
| | - I-C Hoi
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - E Jeffrey
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - A Megrant
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - J Mutus
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - C Neill
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - P J J O'Malley
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - C Quintana
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - P Roushan
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - D Sank
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - A Vainsencher
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - J Wenner
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - T C White
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - A N Cleland
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - John M Martinis
- Department of Physics, University of California, Santa Barbara, California 93106, USA
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9
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Jeffrey E, Sank D, Mutus JY, White TC, Kelly J, Barends R, Chen Y, Chen Z, Chiaro B, Dunsworth A, Megrant A, O'Malley PJJ, Neill C, Roushan P, Vainsencher A, Wenner J, Cleland AN, Martinis JM. Fast accurate state measurement with superconducting qubits. Phys Rev Lett 2014; 112:190504. [PMID: 24877923 DOI: 10.1103/physrevlett.112.190504] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Indexed: 06/03/2023]
Abstract
Faster and more accurate state measurement is required for progress in superconducting qubit experiments with greater numbers of qubits and advanced techniques such as feedback. We have designed a multiplexed measurement system with a bandpass filter that allows fast measurement without increasing environmental damping of the qubits. We use this to demonstrate simultaneous measurement of four qubits on a single superconducting integrated circuit, the fastest of which can be measured to 99.8% accuracy in 140 ns. This accuracy and speed is suitable for advanced multiqubit experiments including surface-code error correction.
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Affiliation(s)
- Evan Jeffrey
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
| | - Daniel Sank
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
| | - J Y Mutus
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
| | - T C White
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
| | - J Kelly
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
| | - R Barends
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
| | - Y Chen
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
| | - Z Chen
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
| | - B Chiaro
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
| | - A Dunsworth
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
| | - A Megrant
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
| | - P J J O'Malley
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
| | - C Neill
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
| | - P Roushan
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
| | - A Vainsencher
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
| | - J Wenner
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
| | - A N Cleland
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
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10
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Jeffrey E, Sank D, Mutus JY, White TC, Kelly J, Barends R, Chen Y, Chen Z, Chiaro B, Dunsworth A, Megrant A, O'Malley PJJ, Neill C, Roushan P, Vainsencher A, Wenner J, Cleland AN, Martinis JM. Fast accurate state measurement with superconducting qubits. Phys Rev Lett 2014; 112:190504. [PMID: 24877923 DOI: 10.1103/physrevlett.112.210501] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Indexed: 05/23/2023]
Abstract
Faster and more accurate state measurement is required for progress in superconducting qubit experiments with greater numbers of qubits and advanced techniques such as feedback. We have designed a multiplexed measurement system with a bandpass filter that allows fast measurement without increasing environmental damping of the qubits. We use this to demonstrate simultaneous measurement of four qubits on a single superconducting integrated circuit, the fastest of which can be measured to 99.8% accuracy in 140 ns. This accuracy and speed is suitable for advanced multiqubit experiments including surface-code error correction.
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Affiliation(s)
- Evan Jeffrey
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
| | - Daniel Sank
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
| | - J Y Mutus
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
| | - T C White
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
| | - J Kelly
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
| | - R Barends
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
| | - Y Chen
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
| | - Z Chen
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
| | - B Chiaro
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
| | - A Dunsworth
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
| | - A Megrant
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
| | - P J J O'Malley
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
| | - C Neill
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
| | - P Roushan
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
| | - A Vainsencher
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
| | - J Wenner
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
| | - A N Cleland
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
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11
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Barends R, Kelly J, Megrant A, Veitia A, Sank D, Jeffrey E, White TC, Mutus J, Fowler AG, Campbell B, Chen Y, Chen Z, Chiaro B, Dunsworth A, Neill C, O’Malley P, Roushan P, Vainsencher A, Wenner J, Korotkov AN, Cleland AN, Martinis JM. Superconducting quantum circuits at the surface code threshold for fault tolerance. Nature 2014; 508:500-3. [DOI: 10.1038/nature13171] [Citation(s) in RCA: 1057] [Impact Index Per Article: 105.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Accepted: 02/24/2014] [Indexed: 11/09/2022]
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12
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Barends R, Kelly J, Megrant A, Sank D, Jeffrey E, Chen Y, Yin Y, Chiaro B, Mutus J, Neill C, O'Malley P, Roushan P, Wenner J, White TC, Cleland AN, Martinis JM. Coherent Josephson qubit suitable for scalable quantum integrated circuits. Phys Rev Lett 2013; 111:080502. [PMID: 24010421 DOI: 10.1103/physrevlett.111.080502] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Indexed: 06/02/2023]
Abstract
We demonstrate a planar, tunable superconducting qubit with energy relaxation times up to 44 μs. This is achieved by using a geometry designed to both minimize radiative loss and reduce coupling to materials-related defects. At these levels of coherence, we find a fine structure in the qubit energy lifetime as a function of frequency, indicating the presence of a sparse population of incoherent, weakly coupled two-level defects. We elucidate this defect physics by experimentally varying the geometry and by a model analysis. Our "Xmon" qubit combines facile fabrication, straightforward connectivity, fast control, and long coherence, opening a viable route to constructing a chip-based quantum computer.
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Affiliation(s)
- R Barends
- Department of Physics, University of California, Santa Barbara, California 93106, USA
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13
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Wenner J, Yin Y, Lucero E, Barends R, Chen Y, Chiaro B, Kelly J, Lenander M, Mariantoni M, Megrant A, Neill C, O'Malley PJJ, Sank D, Vainsencher A, Wang H, White TC, Cleland AN, Martinis JM. Excitation of superconducting qubits from hot nonequilibrium quasiparticles. Phys Rev Lett 2013; 110:150502. [PMID: 25167235 DOI: 10.1103/physrevlett.110.150502] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Revised: 03/04/2013] [Indexed: 06/03/2023]
Abstract
Superconducting qubits probe environmental defects such as nonequilibrium quasiparticles, an important source of decoherence. We show that "hot" nonequilibrium quasiparticles, with energies above the superconducting gap, affect qubits differently from quasiparticles at the gap, implying qubits can probe the dynamic quasiparticle energy distribution. For hot quasiparticles, we predict a non-negligible increase in the qubit excited state probability Pe. By injecting hot quasiparticles into a qubit, we experimentally measure an increase of Pe in semiquantitative agreement with the model and rule out the typically assumed thermal distribution.
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Affiliation(s)
- J Wenner
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - Yi Yin
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - Erik Lucero
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - R Barends
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - Yu Chen
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - B Chiaro
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - J Kelly
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - M Lenander
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - Matteo Mariantoni
- Department of Physics, University of California, Santa Barbara, California 93106, USA and California NanoSystems Institute, University of California, Santa Barbara, California 93106, USA
| | - A Megrant
- Department of Physics, University of California, Santa Barbara, California 93106, USA and Department of Materials, University of California, Santa Barbara, California 93106, USA
| | - C Neill
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - P J J O'Malley
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - D Sank
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - A Vainsencher
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - H Wang
- Department of Physics, University of California, Santa Barbara, California 93106, USA and Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - T C White
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - A N Cleland
- Department of Physics, University of California, Santa Barbara, California 93106, USA and California NanoSystems Institute, University of California, Santa Barbara, California 93106, USA
| | - John M Martinis
- Department of Physics, University of California, Santa Barbara, California 93106, USA and California NanoSystems Institute, University of California, Santa Barbara, California 93106, USA
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14
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Yin Y, Chen Y, Sank D, O'Malley PJJ, White TC, Barends R, Kelly J, Lucero E, Mariantoni M, Megrant A, Neill C, Vainsencher A, Wenner J, Korotkov AN, Cleland AN, Martinis JM. Catch and release of microwave photon states. Phys Rev Lett 2013; 110:107001. [PMID: 23521281 DOI: 10.1103/physrevlett.110.107001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Indexed: 06/01/2023]
Abstract
We demonstrate a superconducting resonator with variable coupling to a measurement transmission line. The resonator coupling can be adjusted through zero to a photon emission rate 1000 times the intrinsic resonator decay rate. We demonstrate the catch and release of photons in the resonator, as well as control of nonclassical Fock states. We also demonstrate the dynamical control of the release waveform of photons from the resonator, a key functionality that will enable high-fidelity quantum state transfer between distant resonators or qubits.
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Affiliation(s)
- Yi Yin
- Department of Physics, University of California, Santa Barbara, California 93106, USA.
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15
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Sank D, Barends R, Bialczak RC, Chen Y, Kelly J, Lenander M, Lucero E, Mariantoni M, Megrant A, Neeley M, O'Malley PJJ, Vainsencher A, Wang H, Wenner J, White TC, Yamamoto T, Yin Y, Cleland AN, Martinis JM. Flux noise probed with real time qubit tomography in a Josephson phase qubit. Phys Rev Lett 2012; 109:067001. [PMID: 23006294 DOI: 10.1103/physrevlett.109.067001] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2011] [Indexed: 06/01/2023]
Abstract
We measure the dependence of qubit phase coherence and flux noise on inductor loop geometry. While wider inductor traces change neither the flux noise power spectrum nor the qubit dephasing time, increased inductance leads to a simultaneous increase in both. Using our new tomographic protocol for measuring low frequency flux noise, we make a direct comparison between the flux noise spectrum and qubit phase decay, finding agreement within 10% of theory.
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Affiliation(s)
- Daniel Sank
- Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
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16
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Mariantoni M, Wang H, Yamamoto T, Neeley M, Bialczak RC, Chen Y, Lenander M, Lucero E, O’Connell AD, Sank D, Weides M, Wenner J, Yin Y, Zhao J, Korotkov AN, Cleland AN, Martinis JM. Implementing the Quantum von Neumann Architecture with Superconducting Circuits. Science 2011; 334:61-5. [DOI: 10.1126/science.1208517] [Citation(s) in RCA: 220] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Matteo Mariantoni
- Department of Physics, University of California, Santa Barbara, CA 93106–9530, USA
- California NanoSystems Institute, University of California, Santa Barbara, CA 93106–9530, USA
| | - H. Wang
- Department of Physics, University of California, Santa Barbara, CA 93106–9530, USA
| | - T. Yamamoto
- Department of Physics, University of California, Santa Barbara, CA 93106–9530, USA
- Green Innovation Research Laboratories, NEC Corporation, Tsukuba, Ibaraki 305-8501, Japan
| | - M. Neeley
- Department of Physics, University of California, Santa Barbara, CA 93106–9530, USA
| | - Radoslaw C. Bialczak
- Department of Physics, University of California, Santa Barbara, CA 93106–9530, USA
| | - Y. Chen
- Department of Physics, University of California, Santa Barbara, CA 93106–9530, USA
| | - M. Lenander
- Department of Physics, University of California, Santa Barbara, CA 93106–9530, USA
| | - Erik Lucero
- Department of Physics, University of California, Santa Barbara, CA 93106–9530, USA
| | - A. D. O’Connell
- Department of Physics, University of California, Santa Barbara, CA 93106–9530, USA
| | - D. Sank
- Department of Physics, University of California, Santa Barbara, CA 93106–9530, USA
| | - M. Weides
- Department of Physics, University of California, Santa Barbara, CA 93106–9530, USA
| | - J. Wenner
- Department of Physics, University of California, Santa Barbara, CA 93106–9530, USA
| | - Y. Yin
- Department of Physics, University of California, Santa Barbara, CA 93106–9530, USA
| | - J. Zhao
- Department of Physics, University of California, Santa Barbara, CA 93106–9530, USA
| | - A. N. Korotkov
- Department of Electrical Engineering, University of California, Riverside, CA 92521, USA
| | - A. N. Cleland
- Department of Physics, University of California, Santa Barbara, CA 93106–9530, USA
- California NanoSystems Institute, University of California, Santa Barbara, CA 93106–9530, USA
| | - John M. Martinis
- Department of Physics, University of California, Santa Barbara, CA 93106–9530, USA
- California NanoSystems Institute, University of California, Santa Barbara, CA 93106–9530, USA
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17
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Bialczak RC, Ansmann M, Hofheinz M, Lenander M, Lucero E, Neeley M, O'Connell AD, Sank D, Wang H, Weides M, Wenner J, Yamamoto T, Cleland AN, Martinis JM. Fast tunable coupler for superconducting qubits. Phys Rev Lett 2011; 106:060501. [PMID: 21405448 DOI: 10.1103/physrevlett.106.060501] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2010] [Indexed: 05/30/2023]
Abstract
A major challenge in the field of quantum computing is the construction of scalable qubit coupling architectures. Here, we demonstrate a novel tunable coupling circuit that allows superconducting qubits to be coupled over long distances. We show that the interqubit coupling strength can be arbitrarily tuned over nanosecond time scales within a sequence that mimics actual use in an algorithm. The coupler has a measured on/off ratio of 1000. The design is self-contained and physically separate from the qubits, allowing the coupler to be used as a module to connect a variety of elements such as qubits, resonators, amplifiers, and readout circuitry over distances much larger than nearest-neighbor. Such design flexibility is likely to be useful for a scalable quantum computer.
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Affiliation(s)
- R C Bialczak
- Department of Physics, University of California, Santa Barbara, California 93106, USA
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18
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Wang H, Mariantoni M, Bialczak RC, Lenander M, Lucero E, Neeley M, O'Connell AD, Sank D, Weides M, Wenner J, Yamamoto T, Yin Y, Zhao J, Martinis JM, Cleland AN. Deterministic entanglement of photons in two superconducting microwave resonators. Phys Rev Lett 2011; 106:060401. [PMID: 21405445 DOI: 10.1103/physrevlett.106.060401] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Indexed: 05/30/2023]
Abstract
Quantum entanglement, one of the defining features of quantum mechanics, has been demonstrated in a variety of nonlinear spinlike systems. Quantum entanglement in linear systems has proven significantly more challenging, as the intrinsic energy level degeneracy associated with linearity makes quantum control more difficult. Here we demonstrate the quantum entanglement of photon states in two independent linear microwave resonators, creating N-photon NOON states (entangled states |N0> + |0N>) as a benchmark demonstration. We use a superconducting quantum circuit that includes Josephson qubits to control and measure the two resonators, and we completely characterize the entangled states with bipartite Wigner tomography. These results demonstrate a significant advance in the quantum control of linear resonators in superconducting circuits.
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Affiliation(s)
- H Wang
- Department of Physics, University of California, Santa Barbara, California 93106, USA
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19
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Neeley M, Bialczak RC, Lenander M, Lucero E, Mariantoni M, O'Connell AD, Sank D, Wang H, Weides M, Wenner J, Yin Y, Yamamoto T, Cleland AN, Martinis JM. Generation of three-qubit entangled states using superconducting phase qubits. Nature 2010; 467:570-3. [PMID: 20882012 DOI: 10.1038/nature09418] [Citation(s) in RCA: 311] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2010] [Accepted: 08/11/2010] [Indexed: 11/09/2022]
Abstract
Entanglement is one of the key resources required for quantum computation, so the experimental creation and measurement of entangled states is of crucial importance for various physical implementations of quantum computers. In superconducting devices, two-qubit entangled states have been demonstrated and used to show violations of Bell's inequality and to implement simple quantum algorithms. Unlike the two-qubit case, where all maximally entangled two-qubit states are equivalent up to local changes of basis, three qubits can be entangled in two fundamentally different ways. These are typified by the states |GHZ>= (|000+ |111>)/ sqrt [2] and |W>= (|001> + |010> + |100>)/ sqrt [3]. Here we demonstrate the operation of three coupled superconducting phase qubits and use them to create and measure |GHZ> and |W>states. The states are fully characterized using quantum state tomography and are shown to satisfy entanglement witnesses, confirming that they are indeed examples of three-qubit entanglement and are not separable into mixtures of two-qubit entanglement.
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Affiliation(s)
- Matthew Neeley
- Department of Physics, University of California, Santa Barbara, California 93106, USA
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20
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Wang H, Hofheinz M, Ansmann M, Bialczak RC, Lucero E, Neeley M, O'Connell AD, Sank D, Weides M, Wenner J, Cleland AN, Martinis JM. Decoherence dynamics of complex photon states in a superconducting circuit. Phys Rev Lett 2009; 103:200404. [PMID: 20365967 DOI: 10.1103/physrevlett.103.200404] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2009] [Indexed: 05/29/2023]
Abstract
Quantum states inevitably decay with time into a probabilistic mixture of classical states due to their interaction with the environment and measurement instrumentation. We present the first measurement of the decoherence dynamics of complex photon states in a condensed-matter system. By controllably preparing a number of distinct quantum-superposed photon states in a superconducting microwave resonator, we show that the subsequent decay dynamics can be quantitatively described by taking into account only two distinct decay channels: energy relaxation and pure dephasing. Our ability to prepare specific initial quantum states allows us to measure the evolution of specific elements in the quantum density matrix in a very detailed manner that can be compared with theory.
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Affiliation(s)
- H Wang
- Department of Physics, University of California, Santa Barbara, California 93106, USA
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21
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Requa MV, Fraikin JL, Stanton MA, Cleland AN. Nanoscale radiofrequency impedance sensors with unconditionally stable tuning. J Appl Phys 2009; 106:74308. [PMID: 19902001 PMCID: PMC2774346 DOI: 10.1063/1.3243315] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2009] [Accepted: 09/09/2009] [Indexed: 05/28/2023]
Abstract
Impedance sensors perform an important role in a number of biosensing applications, including particle counting, sizing, and velocimetry. Detection of nanoparticles, or changes in, e.g., the interfacial Debye-Hückel layer, can also be performed using nanoscale impedance sensors. One method for monitoring changes in the local impedance is to use radiofrequency reflectometry, which when combined with an impedance-matched sensor can afford very high sensitivity with very large detection bandwidth. Maintaining sensitivity and dynamic range, however, requires continuous tuning of the impedance matching network. Here we demonstrate a dual feedback tuning circuit, which allows us to maintain near-perfect impedance matching, even in the presence of long-term drifts in sensor impedance. We apply this tuning technique to a nanoscale interdigitated impedance sensor, designed to allow the direct detection of nanoparticles or real-time monitoring of molecular surface binding. We demonstrate optimal performance of the nanoscale sensor and tuned impedance network both when modulating the concentration of saline to which the sensor is exposed and when electronically switching between sensors configured in a two-element differential array, achieving a stabilization response time of <20 ms.
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22
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Fraikin JL, Requa MV, Cleland AN. Probing the debye layer: capacitance and potential of zero charge measured using a debye-layer transistor. Phys Rev Lett 2009; 102:156601. [PMID: 19518661 DOI: 10.1103/physrevlett.102.156601] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2009] [Indexed: 05/27/2023]
Abstract
We present a unique method for probing the properties of the electrolytic Debye layer, incorporating it as the active element in a novel radio frequency (rf) field-effect transistor. The capacitance of the Debye layer depends nonlinearly on the voltage applied across it, and we exploit this dependence to directly modulate the rf conductance between two nanofabricated interdigitated electrodes. We make quantitative measurements of the Debye-layer capacitance, allowing us to determine the potential of zero charge, a quantity of importance for electrochemistry and impedance-based biosensing.
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Affiliation(s)
- J-L Fraikin
- Department of Physics, University of California, Santa Barbara, California, USA
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23
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Wang H, Hofheinz M, Ansmann M, Bialczak RC, Lucero E, Neeley M, O'Connell AD, Sank D, Wenner J, Cleland AN, Martinis JM. Measurement of the decay of Fock states in a superconducting quantum circuit. Phys Rev Lett 2008; 101:240401. [PMID: 19113602 DOI: 10.1103/physrevlett.101.240401] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2008] [Indexed: 05/27/2023]
Abstract
We demonstrate the controlled generation of Fock states with up to 15 photons in a microwave coplanar waveguide resonator coupled to a superconducting phase qubit. The subsequent decay of the Fock states, due to dissipation, is then monitored by varying the time delay between preparing the state and performing a number-state analysis. We find that the decay dynamics can be described by a master equation where the lifetime of the n-photon Fock state scales as 1/n, in agreement with theory. We have also generated a coherent state in the microwave resonator, and monitored its decay process. We demonstrate that the coherent state maintains a Poisson distribution as it decays, with an average photon number that decreases with the same characteristic decay time as the one-photon Fock state.
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Affiliation(s)
- H Wang
- Department of Physics, University of California, Santa Barbara, California 93106, USA
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24
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Katz N, Neeley M, Ansmann M, Bialczak RC, Hofheinz M, Lucero E, O'Connell A, Wang H, Cleland AN, Martinis JM, Korotkov AN. Reversal of the weak measurement of a quantum state in a superconducting phase qubit. Phys Rev Lett 2008; 101:200401. [PMID: 19113317 DOI: 10.1103/physrevlett.101.200401] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2008] [Indexed: 05/27/2023]
Abstract
We demonstrate in a superconducting qubit the conditional recovery (uncollapsing) of a quantum state after a partial-collapse measurement. A weak measurement extracts information and results in a nonunitary transformation of the qubit state. However, by adding a rotation and a second partial measurement with the same strength, we erase the extracted information, canceling the effect of both measurements. The fidelity of the state recovery is measured using quantum process tomography and found to be above 70% for partial-collapse strength less than 0.6.
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Affiliation(s)
- Nadav Katz
- Department of Physics, University of California, Santa Barbara, California 93106, USA
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25
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Hofheinz M, Weig EM, Ansmann M, Bialczak RC, Lucero E, Neeley M, O’Connell AD, Wang H, Martinis JM, Cleland AN. Generation of Fock states in a superconducting quantum circuit. Nature 2008; 454:310-4. [DOI: 10.1038/nature07136] [Citation(s) in RCA: 408] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2008] [Accepted: 05/23/2008] [Indexed: 11/09/2022]
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26
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Lucero E, Hofheinz M, Ansmann M, Bialczak RC, Katz N, Neeley M, O'Connell AD, Wang H, Cleland AN, Martinis JM. High-fidelity gates in a single josephson qubit. Phys Rev Lett 2008; 100:247001. [PMID: 18643615 DOI: 10.1103/physrevlett.100.247001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2008] [Indexed: 05/26/2023]
Abstract
We demonstrate new experimental procedures for measuring small errors in a superconducting quantum bit (qubit). By carefully separating out gate and measurement errors, we construct a complete error budget and demonstrate single qubit gate fidelities of 0.98, limited by energy relaxation. We also introduce a new metrology tool-- Ramsey interference error filter-that can measure the occupation probability of the state |2> which is outside the computational basis, down to 10{-4}, thereby confirming that our quantum system stays within the qubit manifold during single qubit logic operations.
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Affiliation(s)
- Erik Lucero
- Department of Physics, University of California at Santa Barbara, Broida Hall, Santa Barbara, California 93106, USA
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27
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Bialczak RC, McDermott R, Ansmann M, Hofheinz M, Katz N, Lucero E, Neeley M, O'Connell AD, Wang H, Cleland AN, Martinis JM. 1/f Flux noise in Josephson phase qubits. Phys Rev Lett 2007; 99:187006. [PMID: 17995432 DOI: 10.1103/physrevlett.99.187006] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2007] [Indexed: 05/25/2023]
Abstract
We present a new method to measure 1/f noise in Josephson quantum bits (qubits) that yields low-frequency spectra below 1 Hz. A comparison of the noise taken at positive and negative bias of a phase qubit shows the dominant noise source to be flux noise and not junction critical-current noise, with a magnitude similar to that measured previously in other systems. Theoretical calculations show that the level of flux noise is not compatible with the standard model of noise from two-level state defects in the surface oxides of the films.
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Affiliation(s)
- Radoslaw C Bialczak
- Department of Physics, University of California, Santa Barbara, California 93106, USA
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28
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Abstract
We describe the design, fabrication, and use of a radio frequency reflectometer integrated with a microfluidic system, applied to the very high-throughput measurement of micron-scale particles, passing in a microfluidic channel through the sensor region. The device operates as a microfabricated Coulter counter [U.S. Patent No. 2656508 (1953)], similar to a design we have described previously, but here with significantly improved electrode geometry as well as including electronic tuning of the reflectometer; the two improvements yielding an improvement by more than a factor of 10 in the signal to noise and in the diametric discrimination of single particles. We demonstrate the high-throughput discrimination of polystyrene beads with diameters in the 4-10 microm range, achieving diametric resolutions comparable to the intrinsic spread of diameters in the bead distribution, at rates in excess of 15 x 10(6) beads/h.
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Affiliation(s)
- D K Wood
- Department of Physics, University of California at Santa Barbara, Santa Barbara, California 93106, USA
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29
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Swenson LJ, Wood DK, Cleland AN. Diffusion-based electron thermometry using a three-junction single-electron transistor. Nano Lett 2007; 7:1804-8. [PMID: 17480114 DOI: 10.1021/nl0704329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
We describe a new mK-range nanoscale thermometer, based on a unique three-junction radio frequency single-electron transistor. The three-junction geometry allows separation of the thermal and electronic pathways, providing a potentially significant reduction of measurement-induced Joule heating. A radio frequency embedding tank circuit allows very fast readout. We demonstrate electronic and thermal operation, supported by numerical simulations. Applications to minimal back-action calorimetry and bolometry are discussed.
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Affiliation(s)
- L J Swenson
- Department of Physics, University of California at Santa Barbara, Santa Barbara, California 93106, USA
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30
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Wood DK, Braun GB, Fraikin JL, Swenson LJ, Reich NO, Cleland AN. A feasible approach to all-electronic digital labeling and readout for cell identification. Lab Chip 2007; 7:469-74. [PMID: 17389963 DOI: 10.1039/b616442k] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
We present two critical innovations that enable a unique, purely electronic approach to microfluidic whole-cell analysis, focusing on the problem of cell identification and sorting. We used fully-scalable lithographic techniques to microfabricate digital barcodes, providing a means for low-cost, large volume production. We have demonstrated molecular functionalization of the barcodes, using biotin-streptavidin, as well as human CD4 antibody, and we have successfully linked the barcodes to polystyrene beads using the biotin-streptavidin complex. This functionalization allows unique barcodes to be attached to specific cell types, based on phenotype. We have also implemented an electronic barcode readout scheme, using a radio frequency microsensor integrated in an elastomeric microfluidic channel, that can read individual barcodes at rates in excess of 1000 labels s(-1). The barcodes are biologically compatible, and coupled with the electronic sensing technology, provide a route to compact, inexpensive, disposable cell identification, sorting and purification.
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Affiliation(s)
- D K Wood
- Department of Physics, University of California at Santa Barbara, Santa Barbara, CA 93106, USA
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31
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Steffen M, Ansmann M, Bialczak RC, Katz N, Lucero E, McDermott R, Neeley M, Weig EM, Cleland AN, Martinis JM. Measurement of the Entanglement of Two Superconducting Qubits via State Tomography. Science 2006; 313:1423-5. [PMID: 16960003 DOI: 10.1126/science.1130886] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Demonstration of quantum entanglement, a key resource in quantum computation arising from a nonclassical correlation of states, requires complete measurement of all states in varying bases. By using simultaneous measurement and state tomography, we demonstrated entanglement between two solid-state qubits. Single qubit operations and capacitive coupling between two super-conducting phase qubits were used to generate a Bell-type state. Full two-qubit tomography yielded a density matrix showing an entangled state with fidelity up to 87%. Our results demonstrate a high degree of unitary control of the system, indicating that larger implementations are within reach.
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Affiliation(s)
- Matthias Steffen
- Department of Physics and California Nano Systems Institute, University of California, Santa Barbara, CA 93106, USA
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32
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Steffen M, Ansmann M, McDermott R, Katz N, Bialczak RC, Lucero E, Neeley M, Weig EM, Cleland AN, Martinis JM. State tomography of capacitively shunted phase qubits with high fidelity. Phys Rev Lett 2006; 97:050502. [PMID: 17026085 DOI: 10.1103/physrevlett.97.050502] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2006] [Indexed: 05/12/2023]
Abstract
We introduce a new design concept for superconducting phase quantum bits (qubits) in which we explicitly separate the capacitive element from the Josephson tunnel junction for improved qubit performance. The number of two-level systems that couple to the qubit is thereby reduced by an order of magnitude and the measurement fidelity improves to 90%. This improved design enables the first demonstration of quantum state tomography with superconducting qubits using single-shot measurements.
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Affiliation(s)
- Matthias Steffen
- Department of Physics and California Nanosystems Institute, University of California, Santa Barbara, CA 93106, USA
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33
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Katz N, Ansmann M, Bialczak RC, Lucero E, McDermott R, Neeley M, Steffen M, Weig EM, Cleland AN, Martinis JM, Korotkov AN. Coherent State Evolution in a Superconducting Qubit from Partial-Collapse Measurement. Science 2006; 312:1498-500. [PMID: 16763142 DOI: 10.1126/science.1126475] [Citation(s) in RCA: 141] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Measurement is one of the fundamental building blocks of quantum-information processing systems. Partial measurement, where full wavefunction collapse is not the only outcome, provides a detailed test of the measurement process. We introduce quantum-state tomography in a superconducting qubit that exhibits high-fidelity single-shot measurement. For the two probabilistic outcomes of partial measurement, we find either a full collapse or a coherent yet nonunitary evolution of the state. This latter behavior explicitly confirms modern quantum-measurement theory and may prove important for error-correction algorithms in quantum computation.
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Affiliation(s)
- N Katz
- Department of Physics and California NanoSystems Institute, University of California, Santa Barbara, CA 93106, USA
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34
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Schwab KC, Blencowe MP, Roukes ML, Cleland AN, Girvin SM, Milburn GJ, Ekinci KL. Comment on "Evidence for quantized displacement in macroscopic nanomechanical oscillators". Phys Rev Lett 2005; 95:248901; author reply 248902. [PMID: 16384431 DOI: 10.1103/physrevlett.95.248901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2005] [Indexed: 05/05/2023]
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35
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Braun G, Inagaki K, Estabrook RA, Wood DK, Levy E, Cleland AN, Strouse GF, Reich NO. Gold nanoparticle decoration of DNA on silicon. Langmuir 2005; 21:10699-701. [PMID: 16262339 DOI: 10.1021/la0515367] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Electrostatic assembly of cationic nanoparticles onto the negatively charged backbone of double-stranded DNA has been shown to produce one-dimensional chains with potential use as nanoelectronic components. In this paper, micron long DNA templates stretched on aminosilane- and hexamethyldisilazane-modified silicon surfaces are used to assemble 3.5 nm gold nanoparticles passivated with cationic thiocholine. Atomic force microscopy is used to analyze the density and defects along the approximately 5 nm high structures, with comparison between positively charged and neutral surfaces. Low background adsorption of nanoparticles is facilitated by both these surface chemistries, while the neutral surface yields a more densely packed assembly.
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Affiliation(s)
- Gary Braun
- Department of Chemistry and Biochemistry, Biomolecular Science and Engineering Program, University of California, Santa Barbara, 93106-9510, USA
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36
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Abstract
We report quantitative measurements of the nonlinear response of a radio frequency mechanical resonator with a very high quality factor. We measure the noise-free transitions between the two basins of attraction that appear in the nonlinear regime, and find good agreement with theory. We measure the transition rate response to controlled levels of white noise, and extract the basin activation energy. This allows us to obtain precise values for the relevant frequencies and the cubic nonlinearity in the Duffing oscillator, with applications to parametric sensing.
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Affiliation(s)
- J S Aldridge
- Department of Physics, University of California at Santa Barbara, Santa Barbara, California 93106, USA
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37
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38
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Cleland AN, Geller MR. Superconducting qubit storage and entanglement with nanomechanical resonators. Phys Rev Lett 2004; 93:070501. [PMID: 15324218 DOI: 10.1103/physrevlett.93.070501] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2003] [Revised: 12/15/2003] [Indexed: 05/24/2023]
Abstract
We propose a quantum computing architecture based on the integration of nanomechanical resonators with Josephson-junction phase qubits. The resonators are GHz-frequency, dilatational disk resonators, which couple to the junctions through a piezoelectric interaction. The system is analogous to a collection of tunable few-level atoms (the Josephson junctions) coupled to one or more electromagnetic cavities (the resonators). Our architecture combines desirable features of solid-state and optical approaches and may make quantum computing possible in a scalable, solid-state environment.
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Affiliation(s)
- A N Cleland
- Department of Physics, University of California, Santa Barbara, California 93106, USA
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39
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Schmidt DR, Schoelkopf RJ, Cleland AN. Photon-mediated thermal relaxation of electrons in nanostructures. Phys Rev Lett 2004; 93:045901. [PMID: 15323773 DOI: 10.1103/physrevlett.93.045901] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2003] [Indexed: 05/24/2023]
Abstract
Measurements of the thermal properties of nanoscale electron systems have ignored the effect of electrical noise radiated between the electron gas and the environment, through the electrical leads. Here we calculate the effect of this photon-mediated process, and show that the low-temperature thermal conductance is equal to the quantum of thermal conductance, GQ = pi2kB2T/3h, times a coupling coefficient. We find that, at very low temperatures, the photon conductance is the dominant route for thermal equilibration, while at moderate temperatures this relaxation mode adds one quantum of thermal conductance to that due to phonon transport.
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Affiliation(s)
- D R Schmidt
- Department of Physics, University of California, Santa Barbara, California 93106, USA
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40
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Schwabe NF, Cleland AN, Cross MC, Roukes ML. Perturbation of tunneling processes by mechanical degrees of freedom in mesoscopic junctions. Phys Rev B Condens Matter 1995; 52:12911-12920. [PMID: 9980462 DOI: 10.1103/physrevb.52.12911] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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41
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Cleland AN, Schmidt JM, Clarke J. Influence of the environment on the Coulomb blockade in submicrometer normal-metal tunnel junctions. Phys Rev B Condens Matter 1992; 45:2950-2961. [PMID: 10001845 DOI: 10.1103/physrevb.45.2950] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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42
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Schmidt JM, Cleland AN, Clarke J. Resonant tunneling in small current-biased Josephson junctions. Phys Rev B Condens Matter 1991; 43:229-238. [PMID: 9996207 DOI: 10.1103/physrevb.43.229] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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43
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44
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Cleland AN, Martinis JM, Clarke J. Measurement of the effect of moderate dissipation on macroscopic quantum tunneling. Phys Rev B Condens Matter 1988; 37:5950-5953. [PMID: 9943818 DOI: 10.1103/physrevb.37.5950] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/11/2023]
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45
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Clarke J, Cleland AN, Devoret MH, Esteve D, Martinis JM. Quantum Mechanics of a Macroscopic Variable: The Phase Difference of a Josephson Junction. Science 1988; 239:992-7. [PMID: 17815701 DOI: 10.1126/science.239.4843.992] [Citation(s) in RCA: 82] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Experiments to investigate the quantum behavior of a macroscopic degree of freedom, namely the phase difference across a Josephson tunnel junction, are described. The experiments involve measurements of the escape rate of the junction from its zero voltage state. Low temperature measurements of the escape rate for junctions that are either nearly undamped or moderately damped agree very closely with predictions for macroscopic quantum tunneling, with no adjustable parameters. Microwave spectroscopy reveals quantized energy levels in the potential well of the junction in excellent agreement with quantum-mechanical calculations. The system can be regarded as a "macroscopic nucleus with wires."
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