1
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Kang JH, Yoon T, Lee C, Lim S, Ryu H. Design of high-performance entangling logic in silicon quantum dot systems with Bayesian optimization. Sci Rep 2024; 14:10080. [PMID: 38698015 PMCID: PMC11066012 DOI: 10.1038/s41598-024-60478-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Accepted: 04/23/2024] [Indexed: 05/05/2024] Open
Abstract
Device engineering based on computer-aided simulations is essential to make silicon (Si) quantum bits (qubits) be competitive to commercial platforms based on superconductors and trapped ions. Combining device simulations with the Bayesian optimization (BO), here we propose a systematic design approach that is quite useful to procure fast and precise entangling operations of qubits encoded to electron spins in electrode-driven Si quantum dot (QD) systems. For a target problem of the controlled-X (CNOT) logic operation, we employ BO with the Gaussian process regression to evolve design factors of a Si double QD system to the ones that are optimal in terms of speed and fidelity of a CNOT logic driven by a single microwave pulse. The design framework not only clearly contributes to cost-efficient securing of solutions that enhance performance of the target quantum operation, but can be extended to implement more complicated logics with Si QD structures in experimentally unprecedented ways.
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Affiliation(s)
- Ji-Hoon Kang
- Division of National Supercomputing, Korea Institute of Science and Technology Information, Daejeon, 34141, Republic of Korea
| | - Taehyun Yoon
- Artificial Intelligence Graduate School, Ulsan National Institute of Science and Technology, Ulsan, 44919, Republic of Korea
| | - Chanhui Lee
- Department of Artificial Intelligence, Korea University, Seoul, 02841, Republic of Korea
| | - Sungbin Lim
- Department of Statistics, Korea University, Seoul, 02841, Republic of Korea.
| | - Hoon Ryu
- Division of National Supercomputing, Korea Institute of Science and Technology Information, Daejeon, 34141, Republic of Korea.
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2
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Drmota P, Nadlinger DP, Main D, Nichol BC, Ainley EM, Leichtle D, Mantri A, Kashefi E, Srinivas R, Araneda G, Ballance CJ, Lucas DM. Verifiable Blind Quantum Computing with Trapped Ions and Single Photons. PHYSICAL REVIEW LETTERS 2024; 132:150604. [PMID: 38682960 DOI: 10.1103/physrevlett.132.150604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 01/16/2024] [Indexed: 05/01/2024]
Abstract
We report the first hybrid matter-photon implementation of verifiable blind quantum computing. We use a trapped-ion quantum server and a client-side photonic detection system networked via a fiber-optic quantum link. The availability of memory qubits and deterministic entangling gates enables interactive protocols without postselection-key requirements for any scalable blind server, which previous realizations could not provide. We quantify the privacy at ≲0.03 leaked classical bits per qubit. This experiment demonstrates a path to fully verified quantum computing in the cloud.
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Affiliation(s)
- P Drmota
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - D P Nadlinger
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - D Main
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - B C Nichol
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - E M Ainley
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - D Leichtle
- Laboratoire d'Informatique de Paris 6, CNRS, Sorbonne Université, Paris 75005, France
| | - A Mantri
- Joint Center for Quantum Information and Computer Science, University of Maryland, College Park, Maryland, USA
| | - E Kashefi
- Laboratoire d'Informatique de Paris 6, CNRS, Sorbonne Université, Paris 75005, France
- School of Informatics, University of Edinburgh, Edinburgh EH8 9AB, United Kingdom
| | - R Srinivas
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - G Araneda
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - C J Ballance
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - D M Lucas
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
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3
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Carter AL, O'Reilly J, Toh G, Saha S, Shalaev M, Goetting I, Monroe C. Ion trap with in-vacuum high numerical aperture imaging for a dual-species modular quantum computer. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2024; 95:033201. [PMID: 38477652 DOI: 10.1063/5.0180732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Accepted: 02/25/2024] [Indexed: 03/14/2024]
Abstract
Photonic interconnects between quantum systems will play a central role in both scalable quantum computing and quantum networking. Entanglement of remote qubits via photons has been demonstrated in many platforms; however, improving the rate of entanglement generation will be instrumental for integrating photonic links into modular quantum computers. We present an ion trap system that has the highest reported free-space photon collection efficiency for quantum networking. We use a pair of in-vacuum aspheric lenses, each with a numerical aperture of 0.8, to couple 10(1)% of the 493 nm photons emitted from a 138Ba+ ion into single-mode fibers. We also demonstrate that proximal effects of the lenses on the ion position and motion can be mitigated.
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Affiliation(s)
- Allison L Carter
- Joint Quantum Institute and Department of Physics, University of Maryland, College Park, Maryland 20742, USA
| | - Jameson O'Reilly
- Joint Quantum Institute and Department of Physics, University of Maryland, College Park, Maryland 20742, USA
- Duke Quantum Center, Department of Electrical and Computer Engineering, Department of Physics, Duke University, Durham, North Carolina 27701, USA
| | - George Toh
- Joint Quantum Institute and Department of Physics, University of Maryland, College Park, Maryland 20742, USA
- Duke Quantum Center, Department of Electrical and Computer Engineering, Department of Physics, Duke University, Durham, North Carolina 27701, USA
| | - Sagnik Saha
- Joint Quantum Institute and Department of Physics, University of Maryland, College Park, Maryland 20742, USA
- Duke Quantum Center, Department of Electrical and Computer Engineering, Department of Physics, Duke University, Durham, North Carolina 27701, USA
| | - Mikhail Shalaev
- Duke Quantum Center, Department of Electrical and Computer Engineering, Department of Physics, Duke University, Durham, North Carolina 27701, USA
| | - Isabella Goetting
- Duke Quantum Center, Department of Electrical and Computer Engineering, Department of Physics, Duke University, Durham, North Carolina 27701, USA
| | - Christopher Monroe
- Joint Quantum Institute and Department of Physics, University of Maryland, College Park, Maryland 20742, USA
- Duke Quantum Center, Department of Electrical and Computer Engineering, Department of Physics, Duke University, Durham, North Carolina 27701, USA
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4
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Prasad VK, Cheng F, Fekl U, Jacobsen HA. Applications of noisy quantum computing and quantum error mitigation to "adamantaneland": a benchmarking study for quantum chemistry. Phys Chem Chem Phys 2024; 26:4071-4082. [PMID: 38225897 DOI: 10.1039/d3cp03523a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2024]
Abstract
The field of quantum computing has the potential to transform quantum chemistry. The variational quantum eigensolver (VQE) algorithm has allowed quantum computing to be applied to chemical problems in the noisy intermediate-scale quantum (NISQ) era. Applications of VQE have generally focused on predicting absolute energies instead of chemical properties that are relative energy differences and that are most interesting to chemists studying a chemical problem. We address this shortcoming by constructing a molecular benchmark data set in this work containing isomers of C10H16 and carbocationic rearrangements of C10H15+, calculated at a high-level of theory. Using the data set, we compared noiseless VQE simulations to conventionally performed density functional and wavefunction theory-based methods to understand the quality of results. We also investigated the effectiveness of a quantum state tomography-based error mitigation technique in applications of VQE under noise (simulated and real). Our findings reveal that the use of quantum error mitigation is crucial in the NISQ era and advantageous to yield almost noiseless quality results.
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Affiliation(s)
- Viki Kumar Prasad
- The Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto, 10 Kings College Road, Toronto, Ontario, Canada, M5S 3G4. arno,
- Department of Chemical and Physical Sciences, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, Ontario, Canada, L5L 1C6.
| | - Freeman Cheng
- Department of Computer Science, University of Toronto, 40 St. George Street, Toronto, Ontario, Canada, M5S 2E4
| | - Ulrich Fekl
- Department of Chemical and Physical Sciences, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, Ontario, Canada, L5L 1C6.
| | - Hans-Arno Jacobsen
- The Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto, 10 Kings College Road, Toronto, Ontario, Canada, M5S 3G4. arno,
- Department of Computer Science, University of Toronto, 40 St. George Street, Toronto, Ontario, Canada, M5S 2E4
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5
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Zheng X, Zhao C, Ma Y, Qiao S, Chen S, Zhang Z, Yu M, Xiang B, Lv J, Lu F, Zhou C, Ruan S. High performance on-chip polarization beam splitter at visible wavelengths based on a silicon nitride small-sized ridge waveguide. OPTICS EXPRESS 2023; 31:38419-38429. [PMID: 38017949 DOI: 10.1364/oe.505237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 10/16/2023] [Indexed: 11/30/2023]
Abstract
Due to sensitive scaling of the wavelength and the visible-light absorption properties with the device dimension, traditional passive silicon photonic devices with asymmetric waveguide structures cannot achieve polarization control at the visible wavelengths. In this work, a simple and small polarization beam splitter (PBS) for a broad visible-light band, using a tailored silicon nitride (Si3N4) ridge waveguide, is presented, which is based on the distinct optical distribution of two fundamental orthogonal polarized modes in the ridge waveguide. The bending loss for different bending radii and the optical coupling properties of the fundamental modes for different Si3N4 ridge waveguide configurations are analyzed. A PBS composed of a bending ridge waveguide structure and a triple-waveguide directional coupler was fabricated on the Si3N4 thin film. The TM excitation of the device based on a bending ridge waveguide structure shows a polarization extinction ratio (PER) of ≥ 20 dB with 33 nm bandwidth (624-657 nm) and insertion loss (IL) ≤ 1 dB at the through port. The TE excitation of the device, based on a triple-waveguide directional coupler with coupling efficiency distinction between the TE0 and TM0 modes, shows a PER of ≥ 18 dB with 50 nm bandwidth (580-630 nm) and insertion loss (IL) ≤ 1 dB at the cross port. The on-chip Si3N4 PBS device is found to possess the highest known PER at a visible broadband range and small (43 µm) footprint. It should be useful for novel photonic circuit designs and further exploration of Si3N4 PBSs.
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6
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Zhu D, Shen W, Giani A, Ray-Majumder S, Neculaes B, Johri S. Copula-based risk aggregation with trapped ion quantum computers. Sci Rep 2023; 13:18511. [PMID: 37898631 PMCID: PMC10613293 DOI: 10.1038/s41598-023-44151-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 10/04/2023] [Indexed: 10/30/2023] Open
Abstract
Copulas are mathematical tools for modeling joint probability distributions. In the past 60 years they have become an essential analysis tool on classical computers in various fields. The recent finding that copulas can be expressed as maximally entangled quantum states has revealed a promising approach to practical quantum advantages: performing tasks faster, requiring less memory, or, as we show, yielding better predictions. Studying the scalability of this quantum approach as both the precision and the number of modeled variables increase is crucial for its adoption in real-world applications. In this paper, we successfully apply a Quantum Circuit Born Machine (QCBM) based approach to modeling 3- and 4-variable copulas on trapped ion quantum computers. We study the training of QCBMs with different levels of precision and circuit design on a simulator and a state-of-the-art trapped ion quantum computer. We observe decreased training efficacy due to the increased complexity in parameter optimization as the models scale up. To address this challenge, we introduce an annealing-inspired strategy that dramatically improves the training results. In our end-to-end tests, various configurations of the quantum models make a comparable or better prediction in risk aggregation tasks than the standard classical models.
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Affiliation(s)
- Daiwei Zhu
- IonQ Inc., 4505 Campus Drive, College Park, MD, USA.
| | - Weiwei Shen
- GE Research, One Research Circle, Niskayuna, NY, USA
| | | | | | | | - Sonika Johri
- IonQ Inc., 4505 Campus Drive, College Park, MD, USA
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7
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Jeong J, Jung C, Kim T, Cho DD. Using machine learning to improve multi-qubit state discrimination of trapped ions from uncertain EMCCD measurements. OPTICS EXPRESS 2023; 31:35113-35130. [PMID: 37859250 DOI: 10.1364/oe.491301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Accepted: 08/15/2023] [Indexed: 10/21/2023]
Abstract
This paper proposes a residual network (ResNet)-based convolutional neural network (CNN) model to improve multi-qubit state measurements using an electron-multiplying charge-coupled device (EMCCD). The CNN model is developed to simultaneously use the intensity of pixel values and the shape of ion images in determining the quantum states of ions. In contrast, conventional methods use only the intensity values. In our experiments, the proposed model achieved a 99.53±0.14% mean individual measurement fidelity (MIMF) of 4 trapped ions, reducing the error by 46% when compared to the MIMF of maximum likelihood estimation method of 99.13±0.08%. In addition, it is experimentally shown that the model is also robust against the ion image drift, which was tested by intentionally shifting the ion images.
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8
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Chen S, Cotler J, Huang HY, Li J. The complexity of NISQ. Nat Commun 2023; 14:6001. [PMID: 37752125 PMCID: PMC10522708 DOI: 10.1038/s41467-023-41217-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Accepted: 08/25/2023] [Indexed: 09/28/2023] Open
Abstract
The recent proliferation of NISQ devices has made it imperative to understand their power. In this work, we define and study the complexity class NISQ, which encapsulates problems that can be efficiently solved by a classical computer with access to noisy quantum circuits. We establish super-polynomial separations in the complexity among classical computation, NISQ, and fault-tolerant quantum computation to solve some problems based on modifications of Simon's problems. We then consider the power of NISQ for three well-studied problems. For unstructured search, we prove that NISQ cannot achieve a Grover-like quadratic speedup over classical computers. For the Bernstein-Vazirani problem, we show that NISQ only needs a number of queries logarithmic in what is required for classical computers. Finally, for a quantum state learning problem, we prove that NISQ is exponentially weaker than classical computers with access to noiseless constant-depth quantum circuits.
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Affiliation(s)
- Sitan Chen
- Department of Electrical Engineering and Computer Science, University of California, Berkeley, Berkeley, CA, USA.
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, USA.
| | - Jordan Cotler
- Society of Fellows, Harvard University, Cambridge, MA, USA.
| | - Hsin-Yuan Huang
- Institute for Quantum Information and Matter, CAltech, Pasadena, CA, USA.
- Department of Computing and Mathematical Sciences, CAltech, Pasadena, CA, USA.
| | - Jerry Li
- Microsoft Research AI, Redmond, WA, USA.
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9
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Ramanathan A, Walter ED, Mourigal M, La Pierre HS. Increased Crystal Field Drives Intermediate Coupling and Minimizes Decoherence in Tetravalent Praseodymium Qubits. J Am Chem Soc 2023; 145:17603-17612. [PMID: 37527523 PMCID: PMC10436280 DOI: 10.1021/jacs.3c02820] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Indexed: 08/03/2023]
Abstract
Crystal field (CF) control of rare-earth (RE) ions has been employed to minimize decoherence in qubits and to enhance the effective barrier of single-molecule magnets. The CF approach has been focused on the effects of symmetry on dynamic magnetic properties. Herein, the magnitude of the CF is increased via control of the RE oxidation state. The enhanced 4f metal-ligand covalency in Pr4+ gives rise to CF energy scales that compete with the spin-orbit coupling of Pr4+ and thereby shifts the paradigm from the ionic ζSOC ≫ VCF limit, used to describe trivalent RE-ion, to an intermediate coupling (IC) regime. We examine Pr4+-doped perovskite oxide lattices (BaSnO3 and BaZrO3). These systems are defined by IC which quenches orbital angular momentum. Therefore, the single-ion spin-orbit coupled states in Pr4+ can be chemically tuned. We demonstrate a relatively large hyperfine interaction of Aiso = 1800 MHz for Pr4+, coherent manipulation of the spin with QM = 2ΩRTm, reaching up to ∼400 for 0.1Pr:BSO at T = 5 K, and significant improvement of the temperature at which Tm is limited by T1 (T* = 60 K) compared to other RE ion qubits.
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Affiliation(s)
- Arun Ramanathan
- School
of Chemistry and Biochemistry, Georgia Institute
of Technology, Atlanta, Georgia 30332, United States
| | - Eric D. Walter
- Environmental
Molecular Sciences Laboratory, Pacific Northwest
National Laboratory, Richland, Washington 99352, United States
| | - Martin Mourigal
- School
of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Henry S. La Pierre
- School
of Chemistry and Biochemistry, Georgia Institute
of Technology, Atlanta, Georgia 30332, United States
- Nuclear
and Radiological Engineering and Medical Physics Program, School of
Mechanical Engineering, Georgia Institute
of Technology, Atlanta, Georgia 30332, United States
- Physical
Sciences Division, Pacific Northwest National
Laboratory, Richland, Washington 99352, United States
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10
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Pokharel B, Lidar DA. Demonstration of Algorithmic Quantum Speedup. PHYSICAL REVIEW LETTERS 2023; 130:210602. [PMID: 37295120 DOI: 10.1103/physrevlett.130.210602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2022] [Accepted: 04/20/2023] [Indexed: 06/12/2023]
Abstract
Despite the development of increasingly capable quantum computers, an experimental demonstration of a provable algorithmic quantum speedup employing today's non-fault-tolerant devices has remained elusive. Here, we unequivocally demonstrate such a speedup within the oracular model, quantified in terms of the scaling with the problem size of the time-to-solution metric. We implement the single-shot Bernstein-Vazirani algorithm, which solves the problem of identifying a hidden bitstring that changes after every oracle query, using two different 27-qubit IBM Quantum superconducting processors. The speedup is observed on only one of the two processors when the quantum computation is protected by dynamical decoupling but not without it. The quantum speedup reported here does not rely on any additional assumptions or complexity-theoretic conjectures and solves a bona fide computational problem in the setting of a game with an oracle and a verifier.
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Affiliation(s)
- Bibek Pokharel
- Department of Physics & Astronomy and Center for Quantum Information Science & Technology, University of Southern California, Los Angeles, California 90089, USA
| | - Daniel A Lidar
- Departments of Electrical & Computer Engineering, Chemistry, and Physics & Astronomy, and Center for Quantum Information Science & Technology, University of Southern California, Los Angeles, California 90089, USA
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11
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Oz F, San O, Kara K. An efficient quantum partial differential equation solver with chebyshev points. Sci Rep 2023; 13:7767. [PMID: 37173401 PMCID: PMC10182049 DOI: 10.1038/s41598-023-34966-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Accepted: 05/10/2023] [Indexed: 05/15/2023] Open
Abstract
Differential equations are the foundation of mathematical models representing the universe's physics. Hence, it is significant to solve partial and ordinary differential equations, such as Navier-Stokes, heat transfer, convection-diffusion, and wave equations, to model, calculate and simulate the underlying complex physical processes. However, it is challenging to solve coupled nonlinear high dimensional partial differential equations in classical computers because of the vast amount of required resources and time. Quantum computation is one of the most promising methods that enable simulations of more complex problems. One solver developed for quantum computers is the quantum partial differential equation (PDE) solver, which uses the quantum amplitude estimation algorithm (QAEA). This paper proposes an efficient implementation of the QAEA by utilizing Chebyshev points for numerical integration to design robust quantum PDE solvers. A generic ordinary differential equation, a heat equation, and a convection-diffusion equation are solved. The solutions are compared with the available data to demonstrate the effectiveness of the proposed approach. We show that the proposed implementation provides a two-order accuracy increase with a significant reduction in solution time.
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Affiliation(s)
- Furkan Oz
- School of Mechanical and Aerospace Engineering, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Omer San
- School of Mechanical and Aerospace Engineering, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Kursat Kara
- School of Mechanical and Aerospace Engineering, Oklahoma State University, Stillwater, OK, 74078, USA.
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12
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Wang J, Edlbauer H, Richard A, Ota S, Park W, Shim J, Ludwig A, Wieck AD, Sim HS, Urdampilleta M, Meunier T, Kodera T, Kaneko NH, Sellier H, Waintal X, Takada S, Bäuerle C. Coulomb-mediated antibunching of an electron pair surfing on sound. NATURE NANOTECHNOLOGY 2023:10.1038/s41565-023-01368-5. [PMID: 37169896 DOI: 10.1038/s41565-023-01368-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Accepted: 03/10/2023] [Indexed: 05/13/2023]
Abstract
Electron flying qubits are envisioned as potential information links within a quantum computer, but also promise-like photonic approaches-to serve as self-standing quantum processing units. In contrast to their photonic counterparts, electron-quantum-optics implementations are subject to Coulomb interactions, which provide a direct route to entangle the orbital or spin degree of freedom. However, controlled interaction of flying electrons at the single-particle level has not yet been established experimentally. Here we report antibunching of a pair of single electrons that is synchronously shuttled through a circuit of coupled quantum rails by means of a surface acoustic wave. The in-flight partitioning process exhibits a reciprocal gating effect which allows us to ascribe the observed repulsion predominantly to Coulomb interaction. Our single-shot experiment marks an important milestone on the route to realize a controlled-phase gate for in-flight quantum manipulations.
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Affiliation(s)
- Junliang Wang
- Université Grenoble Alpes, CNRS, Institut Néel, Grenoble, France
| | - Hermann Edlbauer
- Université Grenoble Alpes, CNRS, Institut Néel, Grenoble, France
| | - Aymeric Richard
- Université Grenoble Alpes, CNRS, Institut Néel, Grenoble, France
| | - Shunsuke Ota
- Department of Electrical and Electronic Engineering, Tokyo Institute of Technology, Tokyo, Japan
- National Institute of Advanced Industrial Science and Technology (AIST), National Metrology Institute of Japan (NMIJ), Tsukuba, Japan
| | - Wanki Park
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
| | - Jeongmin Shim
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
- Arnold Sommerfeld Center for Theoretical Physics, Center for NanoScience, and Munich Center for Quantum Science and Technology, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Arne Ludwig
- Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Bochum, Germany
| | - Andreas D Wieck
- Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Bochum, Germany
| | - Heung-Sun Sim
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
| | | | - Tristan Meunier
- Université Grenoble Alpes, CNRS, Institut Néel, Grenoble, France
| | - Tetsuo Kodera
- Department of Electrical and Electronic Engineering, Tokyo Institute of Technology, Tokyo, Japan
| | - Nobu-Hisa Kaneko
- National Institute of Advanced Industrial Science and Technology (AIST), National Metrology Institute of Japan (NMIJ), Tsukuba, Japan
| | - Hermann Sellier
- Université Grenoble Alpes, CNRS, Institut Néel, Grenoble, France
| | - Xavier Waintal
- Université Grenoble Alpes, CEA, INAC-Pheliqs, Grenoble, France
| | - Shintaro Takada
- National Institute of Advanced Industrial Science and Technology (AIST), National Metrology Institute of Japan (NMIJ), Tsukuba, Japan
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13
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Burton WC, Estey B, Hoffman IM, Perry AR, Volin C, Price G. Transport of Multispecies Ion Crystals through a Junction in a Radio-Frequency Paul Trap. PHYSICAL REVIEW LETTERS 2023; 130:173202. [PMID: 37172235 DOI: 10.1103/physrevlett.130.173202] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 03/28/2023] [Indexed: 05/14/2023]
Abstract
We report on the first demonstration of transport of a multispecies ion crystal through a junction in a rf Paul trap. The trap is a two-dimensional surface-electrode trap with an X junction and segmented control electrodes to which time-varying voltages are applied to control the shape and position of potential wells above the trap surface. We transport either a single ^{171}Yb^{+} ion or a crystal composed of a ^{138}Ba^{+} ion cotrapped with the ^{171}Yb^{+} ion to any port of the junction. We characterize the motional excitation by performing multiple round-trips through the junction and back to the initial well position without cooling. The final excitation is then measured using sideband asymmetry. For a single ^{171}Yb^{+} ion, transport with a 4 m/s average speed induces between 0.013±0.001 and 0.014±0.001 quanta of excitation per round-trip, depending on the exit port. For a Ba-Yb crystal, transport at the same speed induces between 0.013±0.001 and 0.030±0.002 quanta per round-trip of excitation to the in-phase axial mode. Excitation in the out-of-phase axial mode ranges from 0.005±0.001 to 0.021±0.001 quanta per round-trip.
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Affiliation(s)
| | - Brian Estey
- Quantinuum, 303 South Technology Court, Broomfield, Colorado 80021, USA
| | - Ian M Hoffman
- Quantinuum, 303 South Technology Court, Broomfield, Colorado 80021, USA
| | - Abigail R Perry
- Quantinuum, 303 South Technology Court, Broomfield, Colorado 80021, USA
| | - Curtis Volin
- Quantinuum, 303 South Technology Court, Broomfield, Colorado 80021, USA
| | - Gabriel Price
- Quantinuum, 303 South Technology Court, Broomfield, Colorado 80021, USA
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14
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Pomarico D, Cosmai L, Facchi P, Lupo C, Pascazio S, Pepe FV. Dynamical Quantum Phase Transitions of the Schwinger Model: Real-Time Dynamics on IBM Quantum. ENTROPY (BASEL, SWITZERLAND) 2023; 25:e25040608. [PMID: 37190397 PMCID: PMC10137833 DOI: 10.3390/e25040608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 03/17/2023] [Accepted: 03/29/2023] [Indexed: 05/17/2023]
Abstract
Simulating the real-time dynamics of gauge theories represents a paradigmatic use case to test the hardware capabilities of a quantum computer, since it can involve non-trivial input states' preparation, discretized time evolution, long-distance entanglement, and measurement in a noisy environment. We implemented an algorithm to simulate the real-time dynamics of a few-qubit system that approximates the Schwinger model in the framework of lattice gauge theories, with specific attention to the occurrence of a dynamical quantum phase transition. Limitations in the simulation capabilities on IBM Quantum were imposed by noise affecting the application of single-qubit and two-qubit gates, which combine in the decomposition of Trotter evolution. The experimental results collected in quantum algorithm runs on IBM Quantum were compared with noise models to characterize the performance in the absence of error mitigation.
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Affiliation(s)
- Domenico Pomarico
- Dipartimento di Fisica, Università di Bari, I-70126 Bari, Italy
- Istituto Nazionale di Fisica Nucleare, Sezione di Bari, I-70126 Bari, Italy
| | - Leonardo Cosmai
- Istituto Nazionale di Fisica Nucleare, Sezione di Bari, I-70126 Bari, Italy
| | - Paolo Facchi
- Dipartimento di Fisica, Università di Bari, I-70126 Bari, Italy
- Istituto Nazionale di Fisica Nucleare, Sezione di Bari, I-70126 Bari, Italy
| | - Cosmo Lupo
- Istituto Nazionale di Fisica Nucleare, Sezione di Bari, I-70126 Bari, Italy
- Dipartimento di Fisica, Politecnico di Bari, I-70126 Bari, Italy
| | - Saverio Pascazio
- Dipartimento di Fisica, Università di Bari, I-70126 Bari, Italy
- Istituto Nazionale di Fisica Nucleare, Sezione di Bari, I-70126 Bari, Italy
| | - Francesco V Pepe
- Dipartimento di Fisica, Università di Bari, I-70126 Bari, Italy
- Istituto Nazionale di Fisica Nucleare, Sezione di Bari, I-70126 Bari, Italy
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15
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Widdows D, Rani J, Pothos EM. Quantum Circuit Components for Cognitive Decision-Making. ENTROPY (BASEL, SWITZERLAND) 2023; 25:e25040548. [PMID: 37190336 PMCID: PMC10138279 DOI: 10.3390/e25040548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 03/10/2023] [Accepted: 03/20/2023] [Indexed: 05/17/2023]
Abstract
This paper demonstrates that some non-classical models of human decision-making can be run successfully as circuits on quantum computers. Since the 1960s, many observed cognitive behaviors have been shown to violate rules based on classical probability and set theory. For example, the order in which questions are posed in a survey affects whether participants answer 'yes' or 'no', so the population that answers 'yes' to both questions cannot be modeled as the intersection of two fixed sets. It can, however, be modeled as a sequence of projections carried out in different orders. This and other examples have been described successfully using quantum probability, which relies on comparing angles between subspaces rather than volumes between subsets. Now in the early 2020s, quantum computers have reached the point where some of these quantum cognitive models can be implemented and investigated on quantum hardware, by representing the mental states in qubit registers, and the cognitive operations and decisions using different gates and measurements. This paper develops such quantum circuit representations for quantum cognitive models, focusing particularly on modeling order effects and decision-making under uncertainty. The claim is not that the human brain uses qubits and quantum circuits explicitly (just like the use of Boolean set theory does not require the brain to be using classical bits), but that the mathematics shared between quantum cognition and quantum computing motivates the exploration of quantum computers for cognition modeling. Key quantum properties include superposition, entanglement, and collapse, as these mathematical elements provide a common language between cognitive models, quantum hardware, and circuit implementations.
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Affiliation(s)
| | - Jyoti Rani
- College of Engineering, University of California, Berkeley, CA 94720, USA
| | - Emmanuel M Pothos
- Department of Psychology, City, University of London, London EC1V 0HB, UK
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16
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Weidner FM, Schwab JD, Wölk S, Rupprecht F, Ikonomi N, Werle SD, Hoffmann S, Kühl M, Kestler HA. Leveraging quantum computing for dynamic analyses of logical networks in systems biology. PATTERNS (NEW YORK, N.Y.) 2023; 4:100705. [PMID: 36960443 PMCID: PMC10028428 DOI: 10.1016/j.patter.2023.100705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 12/12/2022] [Accepted: 02/09/2023] [Indexed: 03/12/2023]
Abstract
The dynamics of cellular mechanisms can be investigated through the analysis of networks. One of the simplest but most popular modeling strategies involves logic-based models. However, these models still face exponential growth in simulation complexity compared with a linear increase in nodes. We transfer this modeling approach to quantum computing and use the upcoming technique in the field to simulate the resulting networks. Leveraging logic modeling in quantum computing has many benefits, including complexity reduction and quantum algorithms for systems biology tasks. To showcase the applicability of our approach to systems biology tasks, we implemented a model of mammalian cortical development. Here, we applied a quantum algorithm to estimate the tendency of the model to reach particular stable conditions and further revert dynamics. Results from two actual quantum processing units and a noisy simulator are presented, and current technical challenges are discussed.
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Affiliation(s)
- Felix M. Weidner
- Institute of Medical Systems Biology, Ulm University, 89081 Ulm, Germany
- International Graduate School of Molecular Medicine, Ulm University, 89081 Ulm, Germany
| | - Julian D. Schwab
- Institute of Medical Systems Biology, Ulm University, 89081 Ulm, Germany
| | - Sabine Wölk
- Institute of Quantum Technologies, DLR Ulm, 89081 Ulm, Germany
| | - Felix Rupprecht
- Institute of Quantum Technologies, DLR Ulm, 89081 Ulm, Germany
| | - Nensi Ikonomi
- Institute of Medical Systems Biology, Ulm University, 89081 Ulm, Germany
- International Graduate School of Molecular Medicine, Ulm University, 89081 Ulm, Germany
| | - Silke D. Werle
- Institute of Medical Systems Biology, Ulm University, 89081 Ulm, Germany
| | - Steve Hoffmann
- Leibniz Institute on Aging, Fritz Lipmann Institute, 07745 Jena, Germany
| | - Michael Kühl
- Institute of Biochemistry and Molecular Biology, Ulm University, 89081 Ulm, Germany
| | - Hans A. Kestler
- Institute of Medical Systems Biology, Ulm University, 89081 Ulm, Germany
- Corresponding author
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17
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Liu SC, Cheng L, Yao GZ, Wang YX, Peng LY. Efficient numerical approach to high-fidelity phase-modulated gates in long chains of trapped ions. Phys Rev E 2023; 107:035304. [PMID: 37072959 DOI: 10.1103/physreve.107.035304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 03/02/2023] [Indexed: 04/20/2023]
Abstract
Almost every quantum circuit is built with two-qubit gates in the current stage, which are crucial to the quantum computing in any platform. The entangling gates based on Mølmer-Sørensen schemes are widely exploited in the trapped-ion system, with the utilization of the collective motional modes of ions and two laser-controlled internal states, which are served as qubits. The key to realize high-fidelity and robust gates is the minimization of the entanglement between the qubits and the motional modes under various sources of errors after the gate operation. In this work, we propose an efficient numerical method to search high-quality solutions for phase-modulated pulses. Instead of directly optimizing a cost function, which contains the fidelity and the robustness of the gates, we convert the problem to the combination of linear algebra and the solution to quadratic equations. Once a solution with the gate fidelity of 1 is found, the laser power can be further reduced while searching on the manifold where the fidelity remains 1. Our method largely overcomes the problem of the convergence and is shown to be effective up to 60 ions, which suffices the need of the gate design in current trapped-ion experiments.
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Affiliation(s)
- Sheng-Chen Liu
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, 100871 Beijing, China
| | - Lin Cheng
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, 100871 Beijing, China
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
| | - Gui-Zhong Yao
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, 100871 Beijing, China
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
| | - Ying-Xiang Wang
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, 100871 Beijing, China
| | - Liang-You Peng
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, 100871 Beijing, China
- Collaborative Innovation Center of Quantum Matter, Beijing 100871, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, 030006 Taiyuan, China
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
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18
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Akhtar M, Bonus F, Lebrun-Gallagher FR, Johnson NI, Siegele-Brown M, Hong S, Hile SJ, Kulmiya SA, Weidt S, Hensinger WK. A high-fidelity quantum matter-link between ion-trap microchip modules. Nat Commun 2023; 14:531. [PMID: 36754957 PMCID: PMC9908934 DOI: 10.1038/s41467-022-35285-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 11/25/2022] [Indexed: 02/10/2023] Open
Abstract
System scalability is fundamental for large-scale quantum computers (QCs) and is being pursued over a variety of hardware platforms. For QCs based on trapped ions, architectures such as the quantum charge-coupled device (QCCD) are used to scale the number of qubits on a single device. However, the number of ions that can be hosted on a single quantum computing module is limited by the size of the chip being used. Therefore, a modular approach is of critical importance and requires quantum connections between individual modules. Here, we present the demonstration of a quantum matter-link in which ion qubits are transferred between adjacent QC modules. Ion transport between adjacent modules is realised at a rate of 2424 s-1 and with an infidelity associated with ion loss during transport below 7 × 10-8. Furthermore, we show that the link does not measurably impact the phase coherence of the qubit. The quantum matter-link constitutes a practical mechanism for the interconnection of QCCD devices. Our work will facilitate the implementation of modular QCs capable of fault-tolerant utility-scale quantum computation.
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Affiliation(s)
- M. Akhtar
- grid.12082.390000 0004 1936 7590Sussex Centre for Quantum Technologies, University of Sussex, Brighton, BN1 9QH UK ,Universal Quantum Ltd, Brighton, BN1 6SB UK
| | - F. Bonus
- Universal Quantum Ltd, Brighton, BN1 6SB UK ,grid.83440.3b0000000121901201Department of Physics and Astronomy, University College London, London, WC1E 6BT UK
| | - F. R. Lebrun-Gallagher
- grid.12082.390000 0004 1936 7590Sussex Centre for Quantum Technologies, University of Sussex, Brighton, BN1 9QH UK ,Universal Quantum Ltd, Brighton, BN1 6SB UK
| | - N. I. Johnson
- grid.12082.390000 0004 1936 7590Sussex Centre for Quantum Technologies, University of Sussex, Brighton, BN1 9QH UK
| | - M. Siegele-Brown
- grid.12082.390000 0004 1936 7590Sussex Centre for Quantum Technologies, University of Sussex, Brighton, BN1 9QH UK
| | - S. Hong
- grid.12082.390000 0004 1936 7590Sussex Centre for Quantum Technologies, University of Sussex, Brighton, BN1 9QH UK
| | - S. J. Hile
- grid.12082.390000 0004 1936 7590Sussex Centre for Quantum Technologies, University of Sussex, Brighton, BN1 9QH UK
| | - S. A. Kulmiya
- grid.12082.390000 0004 1936 7590Sussex Centre for Quantum Technologies, University of Sussex, Brighton, BN1 9QH UK ,grid.5337.20000 0004 1936 7603Quantum Engineering Centre for Doctoral Training, University of Bristol, Bristol, BS8 1TH UK
| | - S. Weidt
- grid.12082.390000 0004 1936 7590Sussex Centre for Quantum Technologies, University of Sussex, Brighton, BN1 9QH UK ,Universal Quantum Ltd, Brighton, BN1 6SB UK
| | - W. K. Hensinger
- grid.12082.390000 0004 1936 7590Sussex Centre for Quantum Technologies, University of Sussex, Brighton, BN1 9QH UK ,Universal Quantum Ltd, Brighton, BN1 6SB UK
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19
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Blunt NS, Camps J, Crawford O, Izsák R, Leontica S, Mirani A, Moylett AE, Scivier SA, Sünderhauf C, Schopf P, Taylor JM, Holzmann N. Perspective on the Current State-of-the-Art of Quantum Computing for Drug Discovery Applications. J Chem Theory Comput 2022; 18:7001-7023. [PMID: 36355616 DOI: 10.1021/acs.jctc.2c00574] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Computational chemistry is an essential tool in the pharmaceutical industry. Quantum computing is a fast evolving technology that promises to completely shift the computational capabilities in many areas of chemical research by bringing into reach currently impossible calculations. This perspective illustrates the near-future applicability of quantum computation of molecules to pharmaceutical problems. We briefly summarize and compare the scaling properties of state-of-the-art quantum algorithms and provide novel estimates of the quantum computational cost of simulating progressively larger embedding regions of a pharmaceutically relevant covalent protein-drug complex involving the drug Ibrutinib. Carrying out these calculations requires an error-corrected quantum architecture that we describe. Our estimates showcase that recent developments on quantum phase estimation algorithms have dramatically reduced the quantum resources needed to run fully quantum calculations in active spaces of around 50 orbitals and electrons, from estimated over 1000 years using the Trotterization approach to just a few days with sparse qubitization, painting a picture of fast and exciting progress in this nascent field.
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Affiliation(s)
- Nick S Blunt
- Riverlane, St. Andrews House, 59 St. Andrews Street, Cambridge CB2 3BZ, United Kingdom
| | - Joan Camps
- Riverlane, St. Andrews House, 59 St. Andrews Street, Cambridge CB2 3BZ, United Kingdom
| | - Ophelia Crawford
- Riverlane, St. Andrews House, 59 St. Andrews Street, Cambridge CB2 3BZ, United Kingdom
| | - Róbert Izsák
- Riverlane, St. Andrews House, 59 St. Andrews Street, Cambridge CB2 3BZ, United Kingdom
| | - Sebastian Leontica
- Riverlane, St. Andrews House, 59 St. Andrews Street, Cambridge CB2 3BZ, United Kingdom
| | - Arjun Mirani
- Riverlane, St. Andrews House, 59 St. Andrews Street, Cambridge CB2 3BZ, United Kingdom
| | - Alexandra E Moylett
- Riverlane, St. Andrews House, 59 St. Andrews Street, Cambridge CB2 3BZ, United Kingdom
| | - Sam A Scivier
- Riverlane, St. Andrews House, 59 St. Andrews Street, Cambridge CB2 3BZ, United Kingdom
| | - Christoph Sünderhauf
- Riverlane, St. Andrews House, 59 St. Andrews Street, Cambridge CB2 3BZ, United Kingdom
| | - Patrick Schopf
- Astex Pharmaceuticals, 436 Cambridge Science Park, Cambridge CB4 0QA, United Kingdom
| | - Jacob M Taylor
- Riverlane, St. Andrews House, 59 St. Andrews Street, Cambridge CB2 3BZ, United Kingdom
| | - Nicole Holzmann
- Riverlane, St. Andrews House, 59 St. Andrews Street, Cambridge CB2 3BZ, United Kingdom.,Astex Pharmaceuticals, 436 Cambridge Science Park, Cambridge CB4 0QA, United Kingdom
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20
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Noise-robust optimization of quantum machine learning models for polymer properties using a simulator and validated on the IonQ quantum computer. Sci Rep 2022; 12:19003. [PMID: 36347908 PMCID: PMC9643424 DOI: 10.1038/s41598-022-22940-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Accepted: 10/21/2022] [Indexed: 11/09/2022] Open
Abstract
Quantum machine learning for predicting the physical properties of polymer materials based on the molecular descriptors of monomers was investigated. Under the stochastic variation of the expected predicted values obtained from quantum circuits due to finite sampling, the methods proposed in previous works did not make sufficient progress in optimizing the parameters. To enable parameter optimization despite the presence of stochastic variations in the expected values, quantum circuits that improve prediction accuracy without increasing the number of parameters and parameter optimization methods that are robust to stochastic variations in the expected predicted values, were investigated. The multi-scale entanglement renormalization ansatz circuit improved the prediction accuracy without increasing the number of parameters. The stochastic gradient descent method using the parameter-shift rule for gradient calculation was shown to be robust to sampling variability in the expected value. Finally, the quantum machine learning model was trained on an actual ion-trap quantum computer. At each optimization step, the coefficient of determination \documentclass[12pt]{minimal}
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\begin{document}$$R^{2}$$\end{document}R2 improved equally on the actual machine and simulator, indicating that our findings enable the training of quantum circuits on the actual quantum computer to the same extent as on the simulator.
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21
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Cross-platform comparison of arbitrary quantum states. Nat Commun 2022; 13:6620. [PMID: 36333309 PMCID: PMC9636372 DOI: 10.1038/s41467-022-34279-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 10/18/2022] [Indexed: 11/06/2022] Open
Abstract
As we approach the era of quantum advantage, when quantum computers (QCs) can outperform any classical computer on particular tasks, there remains the difficult challenge of how to validate their performance. While algorithmic success can be easily verified in some instances such as number factoring or oracular algorithms, these approaches only provide pass/fail information of executing specific tasks for a single QC. On the other hand, a comparison between different QCs preparing nominally the same arbitrary circuit provides an insight for generic validation: a quantum computation is only as valid as the agreement between the results produced on different QCs. Such an approach is also at the heart of evaluating metrological standards such as disparate atomic clocks. In this paper, we report a cross-platform QC comparison using randomized and correlated measurements that results in a wealth of information on the QC systems. We execute several quantum circuits on widely different physical QC platforms and analyze the cross-platform state fidelities. Efficient protocols for comparing quantum states generated on different quantum computing platforms are becoming increasingly important. Zhu et al. demonstrate cross-platform verification using randomized measurements that allow for scaling to larger systems as compared to full quantum state tomography.
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22
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Buffoni L, Gherardini S, Zambrini Cruzeiro E, Omar Y. Third Law of Thermodynamics and the Scaling of Quantum Computers. PHYSICAL REVIEW LETTERS 2022; 129:150602. [PMID: 36269957 DOI: 10.1103/physrevlett.129.150602] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 08/31/2022] [Accepted: 09/01/2022] [Indexed: 06/16/2023]
Abstract
The third law of thermodynamics, also known as the Nernst unattainability principle, puts a fundamental bound on how close a system, whether classical or quantum, can be cooled to a temperature near to absolute zero. On the other hand, a fundamental assumption of quantum computing is to start each computation from a register of qubits initialized in a pure state, i.e., at zero temperature. These conflicting aspects, at the interface between quantum computing and thermodynamics, are often overlooked or, at best, addressed only at a single-qubit level. In this Letter, we argue how the existence of a small but finite effective temperature, which makes the initial state a mixed state, poses a real challenge to the fidelity constraints required for the scaling of quantum computers. Our theoretical results, carried out for a generic quantum circuit with N-qubit input states, are validated by test runs performed on a real quantum processor.
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Affiliation(s)
| | - Stefano Gherardini
- PQI-Portuguese Quantum Institute, 1049-001 Lisboa, Portugal
- CNR-INO, Area Science Park, Basovizza, I-34149 Trieste, Italy
- LENS, University of Florence, via G. Sansone 1, I-50019 Sesto Fiorentino, Italy
| | | | - Yasser Omar
- PQI-Portuguese Quantum Institute, 1049-001 Lisboa, Portugal
- Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal
- Centro de Física e Engenharia de Materiais Avançados (CeFEMA), Physics of Information and Quantum Technologies Group, 1049-001 Lisboa, Portugal
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23
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Yarkoni S, Raponi E, Bäck T, Schmitt S. Quantum annealing for industry applications: introduction and review. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2022; 85:104001. [PMID: 36001953 DOI: 10.1088/1361-6633/ac8c54] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 08/24/2022] [Indexed: 06/15/2023]
Abstract
Quantum annealing (QA) is a heuristic quantum optimization algorithm that can be used to solve combinatorial optimization problems. In recent years, advances in quantum technologies have enabled the development of small- and intermediate-scale quantum processors that implement the QA algorithm for programmable use. Specifically, QA processors produced by D-Wave systems have been studied and tested extensively in both research and industrial settings across different disciplines. In this paper we provide a literature review of the theoretical motivations for QA as a heuristic quantum optimization algorithm, the software and hardware that is required to use such quantum processors, and the state-of-the-art applications and proofs-of-concepts that have been demonstrated using them. The goal of our review is to provide a centralized and condensed source regarding applications of QA technology. We identify the advantages, limitations, and potential of QA for both researchers and practitioners from various fields.
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24
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Jones EB, Hillberry LE, Jones MT, Fasihi M, Roushan P, Jiang Z, Ho A, Neill C, Ostby E, Graf P, Kapit E, Carr LD. Small-world complex network generation on a digital quantum processor. Nat Commun 2022; 13:4483. [PMID: 35918333 PMCID: PMC9345974 DOI: 10.1038/s41467-022-32056-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 07/13/2022] [Indexed: 11/09/2022] Open
Abstract
Quantum cellular automata (QCA) evolve qubits in a quantum circuit depending only on the states of their neighborhoods and model how rich physical complexity can emerge from a simple set of underlying dynamical rules. The inability of classical computers to simulate large quantum systems hinders the elucidation of quantum cellular automata, but quantum computers offer an ideal simulation platform. Here, we experimentally realize QCA on a digital quantum processor, simulating a one-dimensional Goldilocks rule on chains of up to 23 superconducting qubits. We calculate calibrated and error-mitigated population dynamics and complex network measures, which indicate the formation of small-world mutual information networks. These networks decohere at fixed circuit depth independent of system size, the largest of which corresponding to 1,056 two-qubit gates. Such computations may enable the employment of QCA in applications like the simulation of strongly-correlated matter or beyond-classical computational demonstrations.
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Affiliation(s)
- Eric B Jones
- National Renewable Energy Laboratory, Golden, CO, 80401, USA. .,ColdQuanta Inc., Boulder, CO, 80301, USA.
| | | | - Matthew T Jones
- Department of Physics, Colorado School of Mines, Golden, CO, 80401, USA.,NVIDIA Corporation, Boulder, CO, 80302, USA
| | - Mina Fasihi
- Department of Physics, Colorado School of Mines, Golden, CO, 80401, USA
| | | | - Zhang Jiang
- Google Quantum AI, Santa Barbara, CA, 93117, USA
| | - Alan Ho
- Google Quantum AI, Santa Barbara, CA, 93117, USA
| | | | - Eric Ostby
- Google Quantum AI, Santa Barbara, CA, 93117, USA
| | - Peter Graf
- National Renewable Energy Laboratory, Golden, CO, 80401, USA
| | - Eliot Kapit
- Department of Physics, Colorado School of Mines, Golden, CO, 80401, USA. .,Quantum Engineering Program, Colorado School of Mines, Golden, CO, 80401, USA.
| | - Lincoln D Carr
- Department of Physics, Colorado School of Mines, Golden, CO, 80401, USA. .,Quantum Engineering Program, Colorado School of Mines, Golden, CO, 80401, USA.
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25
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Experimental Demonstration of an Efficient Mach–Zehnder Modulator Bias Control for Quantum Key Distribution Systems. ELECTRONICS 2022. [DOI: 10.3390/electronics11142207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
A Mach–Zehnder modulator (MZM) is necessary for implementing a decoy-state protocol in a practical quantum key distribution (QKD) system. However, an MZM bias control method optimized for QKD systems has been missing to date. In this study, we propose an MZM bias control method using N (≥2) diagnostic pulses. The proposed method can be efficiently applied to a QKD system without any additional hardware such as light sources or detectors. Furthermore, it does not reduce the key rate significantly because it uses time slots allocated to existing decoy pulses. We conducted an experimental demonstration of the proposed method in a field-deployed 1 × 3 QKD network and a laboratory test. It is shown that our method can maintain the MZM extinction ratio stably over 20 dB (bit error rate ≤1%), even in an actual network environment for a significant period. Consequently, we achieved successful QKD performances.
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26
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Celik OT, Sarabalis CJ, Mayor FM, Stokowski HS, Herrmann JF, McKenna TP, Lee NRA, Jiang W, Multani KKS, Safavi-Naeini AH. High-bandwidth CMOS-voltage-level electro-optic modulation of 780 nm light in thin-film lithium niobate. OPTICS EXPRESS 2022; 30:23177-23186. [PMID: 36225003 DOI: 10.1364/oe.460119] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Accepted: 05/30/2022] [Indexed: 06/16/2023]
Abstract
Integrated photonics operating at visible-near-infrared (VNIR) wavelengths offer scalable platforms for advancing optical systems for addressing atomic clocks, sensors, and quantum computers. The complexity of free-space control optics causes limited addressability of atoms and ions, and this remains an impediment on scalability and cost. Networks of Mach-Zehnder interferometers can overcome challenges in addressing atoms by providing high-bandwidth electro-optic control of multiple output beams. Here, we demonstrate a VNIR Mach-Zehnder interferometer on lithium niobate on sapphire with a CMOS voltage-level compatible full-swing voltage of 4.2 V and an electro-optic bandwidth of 2.7 GHz occupying only 0.35 mm2. Our waveguides exhibit 1.6 dB/cm propagation loss and our microring resonators have intrinsic quality factors of 4.4 × 105. This specialized platform for VNIR integrated photonics can open new avenues for addressing large arrays of qubits with high precision and negligible cross-talk.
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27
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Bluvstein D, Levine H, Semeghini G, Wang TT, Ebadi S, Kalinowski M, Keesling A, Maskara N, Pichler H, Greiner M, Vuletić V, Lukin MD. A quantum processor based on coherent transport of entangled atom arrays. Nature 2022; 604:451-456. [PMID: 35444318 PMCID: PMC9021024 DOI: 10.1038/s41586-022-04592-6] [Citation(s) in RCA: 62] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 02/28/2022] [Indexed: 11/23/2022]
Abstract
The ability to engineer parallel, programmable operations between desired qubits within a quantum processor is key for building scalable quantum information systems1,2. In most state-of-the-art approaches, qubits interact locally, constrained by the connectivity associated with their fixed spatial layout. Here we demonstrate a quantum processor with dynamic, non-local connectivity, in which entangled qubits are coherently transported in a highly parallel manner across two spatial dimensions, between layers of single- and two-qubit operations. Our approach makes use of neutral atom arrays trapped and transported by optical tweezers; hyperfine states are used for robust quantum information storage, and excitation into Rydberg states is used for entanglement generation3–5. We use this architecture to realize programmable generation of entangled graph states, such as cluster states and a seven-qubit Steane code state6,7. Furthermore, we shuttle entangled ancilla arrays to realize a surface code state with thirteen data and six ancillary qubits8 and a toric code state on a torus with sixteen data and eight ancillary qubits9. Finally, we use this architecture to realize a hybrid analogue–digital evolution2 and use it for measuring entanglement entropy in quantum simulations10–12, experimentally observing non-monotonic entanglement dynamics associated with quantum many-body scars13,14. Realizing a long-standing goal, these results provide a route towards scalable quantum processing and enable applications ranging from simulation to metrology. A quantum processer is realized using arrays of neutral atoms that are transported in a parallel manner by optical tweezers during computations, and used for quantum error correction and simulations.
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Affiliation(s)
- Dolev Bluvstein
- Department of Physics, Harvard University, Cambridge, MA, USA
| | - Harry Levine
- Department of Physics, Harvard University, Cambridge, MA, USA.,AWS Center for Quantum Computing, Pasadena, CA, USA
| | | | - Tout T Wang
- Department of Physics, Harvard University, Cambridge, MA, USA
| | - Sepehr Ebadi
- Department of Physics, Harvard University, Cambridge, MA, USA
| | | | - Alexander Keesling
- Department of Physics, Harvard University, Cambridge, MA, USA.,QuEra Computing Inc., Boston, MA, USA
| | - Nishad Maskara
- Department of Physics, Harvard University, Cambridge, MA, USA
| | - Hannes Pichler
- Institute for Theoretical Physics, University of Innsbruck, Innsbruck, Austria.,Institute for Quantum Optics and Quantum Information, Austrian Academy of Sciences, Innsbruck, Austria
| | - Markus Greiner
- Department of Physics, Harvard University, Cambridge, MA, USA
| | - Vladan Vuletić
- Department of Physics and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Mikhail D Lukin
- Department of Physics, Harvard University, Cambridge, MA, USA.
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28
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Erickson SD, Wu JJ, Hou PY, Cole DC, Geller S, Kwiatkowski A, Glancy S, Knill E, Slichter DH, Wilson AC, Leibfried D. High-Fidelity Indirect Readout of Trapped-Ion Hyperfine Qubits. PHYSICAL REVIEW LETTERS 2022; 128:160503. [PMID: 35522486 DOI: 10.1103/physrevlett.128.160503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Accepted: 03/17/2022] [Indexed: 06/14/2023]
Abstract
We propose and demonstrate a protocol for high-fidelity indirect readout of trapped ion hyperfine qubits, where the state of a ^{9}Be^{+} qubit ion is mapped to a ^{25}Mg^{+} readout ion using laser-driven Raman transitions. By partitioning the ^{9}Be^{+} ground-state hyperfine manifold into two subspaces representing the two qubit states and choosing appropriate laser parameters, the protocol can be made robust to spontaneous photon scattering errors on the Raman transitions, enabling repetition for increased readout fidelity. We demonstrate combined readout and back-action errors for the two subspaces of 1.2_{-0.6}^{+1.1}×10^{-4} and 0_{-0}^{+1.9}×10^{-5} with 68% confidence while avoiding decoherence of spectator qubits due to stray resonant light that is inherent to direct fluorescence detection.
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Affiliation(s)
- Stephen D Erickson
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - Jenny J Wu
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - Pan-Yu Hou
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - Daniel C Cole
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
| | - Shawn Geller
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - Alex Kwiatkowski
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - Scott Glancy
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
| | - Emanuel Knill
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
- Center for Theory of Quantum Matter, University of Colorado, Boulder, Colorado 80309, USA
| | - Daniel H Slichter
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
| | - Andrew C Wilson
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
| | - Dietrich Leibfried
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
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29
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Kundu K, White JRK, Moehring SA, Yu JM, Ziller JW, Furche F, Evans WJ, Hill S. A 9.2-GHz clock transition in a Lu(II) molecular spin qubit arising from a 3,467-MHz hyperfine interaction. Nat Chem 2022; 14:392-397. [PMID: 35288686 DOI: 10.1038/s41557-022-00894-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Accepted: 01/13/2022] [Indexed: 11/09/2022]
Abstract
Spins in molecules are particularly attractive targets for next-generation quantum technologies, enabling chemically programmable qubits and potential for scale-up via self-assembly. Here we report the observation of one of the largest hyperfine interactions for a molecular system, Aiso = 3,467 ± 50 MHz, as well as a very large associated clock transition. This is achieved through chemical control of the degree of s-orbital mixing into the spin-bearing d orbital associated with a series of spin-½ La(II) and Lu(II) complexes. Increased s-orbital character reduces spin-orbit coupling and enhances the electron-nuclear Fermi contact interaction. Both outcomes are advantageous for quantum applications. The former reduces spin-lattice relaxation, and the latter maximizes the hyperfine interaction, which, in turn, generates a 9-GHz clock transition, leading to an increase in phase memory time from 1.0 ± 0.4 to 12 ± 1 μs for one of the Lu(II) complexes. These findings suggest strategies for the development of molecular quantum technologies, akin to trapped ion systems.
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Affiliation(s)
- Krishnendu Kundu
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL, USA
| | | | | | - Jason M Yu
- Department of Chemistry, University of California, Irvine, CA, USA
| | - Joseph W Ziller
- Department of Chemistry, University of California, Irvine, CA, USA
| | - Filipp Furche
- Department of Chemistry, University of California, Irvine, CA, USA.
| | - William J Evans
- Department of Chemistry, University of California, Irvine, CA, USA.
| | - Stephen Hill
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL, USA. .,Department of Physics, Florida State University, Tallahassee, FL, USA.
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30
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An D, Alonso AM, Matthiesen C, Häffner H. Coupling Two Laser-Cooled Ions via a Room-Temperature Conductor. PHYSICAL REVIEW LETTERS 2022; 128:063201. [PMID: 35213172 DOI: 10.1103/physrevlett.128.063201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 11/22/2021] [Indexed: 06/14/2023]
Abstract
We demonstrate coupling between the motions of two independently trapped ions with a separation distance of 620 μm. The ion-ion interaction is enhanced via a room-temperature electrically floating metallic wire which connects two surface traps. Tuning the motion of both ions into resonance, we show flow of energy with a coupling rate of 11 Hz. Quantum-coherent coupling is hindered by strong surface electric-field noise in our device. Our ion-wire-ion system demonstrates that room-temperature conductors can be used to mediate and tune interactions between independently trapped charges over distances beyond those achievable with free-space dipole-dipole coupling. This technology may be used to sympathetically cool or entangle remotely trapped charges and enable coupling between disparate physical systems.
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Affiliation(s)
- Da An
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - Alberto M Alonso
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - Clemens Matthiesen
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - Hartmut Häffner
- Department of Physics, University of California, Berkeley, California 94720, USA
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31
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Quantum Computing With Trapped Ions: An Overview. IEEE NANOTECHNOLOGY MAGAZINE 2022. [DOI: 10.1109/mnano.2022.3175384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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32
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Qian Y, Zhou Y, Wu B, Chen H, Xu S, Wang Y, Zhang P, Li G, Xu Q, Zhou W, Xu X, Wang H. Novel Variants of the SMARCA4 Gene Associated with Autistic Features Rather Than Typical Coffin-Siris Syndrome in Eight Chinese Pediatric Patients. J Autism Dev Disord 2021; 52:5033-5041. [PMID: 34813034 DOI: 10.1007/s10803-021-05365-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/07/2021] [Indexed: 11/29/2022]
Abstract
Autism spectrum disorders (ASDs) are a group of neurodevelopmental-related disorders with a high genetic risk. Recently, chromatin remodeling factors have been found to be related to ASDs. SMARCA4 is such a catalytic subunit of the chromatin-remodeling complex. In this report, we identified seven novel missense variants in the SMARCA4 gene from eight pediatric patients. All eight patients had moderate to severe intellectual disability, and seven showed autistic/likely autistic features. Compared with the patients reported in the literature, our patients were less likely to show craniofacial or finger/toe anomalies. Our findings further supported that SMARCA4 is associated with ASDs. We suggest that individuals with the abovementioned phenotypes should consider genetic testing.
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Affiliation(s)
- Yanyan Qian
- Center of Molecular Medicine, Pediatrics Research Institute, Children's Hospital of Fudan University, National Children's Medical Center, 399 Wanyuan Road, Shanghai, 201102, China
| | - Yuanfeng Zhou
- Neurology Department, Children's Hospital of Fudan University, National Children's Medical Center, Shanghai, 201102, China
| | - Bingbing Wu
- Center of Molecular Medicine, Pediatrics Research Institute, Children's Hospital of Fudan University, National Children's Medical Center, 399 Wanyuan Road, Shanghai, 201102, China
| | - Huiyao Chen
- Center of Molecular Medicine, Pediatrics Research Institute, Children's Hospital of Fudan University, National Children's Medical Center, 399 Wanyuan Road, Shanghai, 201102, China
| | - Suzhen Xu
- Center of Molecular Medicine, Pediatrics Research Institute, Children's Hospital of Fudan University, National Children's Medical Center, 399 Wanyuan Road, Shanghai, 201102, China
| | - Yao Wang
- Center of Molecular Medicine, Pediatrics Research Institute, Children's Hospital of Fudan University, National Children's Medical Center, 399 Wanyuan Road, Shanghai, 201102, China
| | - Ping Zhang
- Center of Molecular Medicine, Pediatrics Research Institute, Children's Hospital of Fudan University, National Children's Medical Center, 399 Wanyuan Road, Shanghai, 201102, China
| | - Gang Li
- Center of Molecular Medicine, Pediatrics Research Institute, Children's Hospital of Fudan University, National Children's Medical Center, 399 Wanyuan Road, Shanghai, 201102, China
| | - Qiong Xu
- Department of Child Health Care, Children's Hospital of Fudan University, National Children's Medical Center, 399 Wanyuan Road, Shanghai, 201102, China
| | - Wenhao Zhou
- Center of Molecular Medicine, Pediatrics Research Institute, Children's Hospital of Fudan University, National Children's Medical Center, 399 Wanyuan Road, Shanghai, 201102, China
| | - Xiu Xu
- Department of Child Health Care, Children's Hospital of Fudan University, National Children's Medical Center, 399 Wanyuan Road, Shanghai, 201102, China.
| | - Huijun Wang
- Center of Molecular Medicine, Pediatrics Research Institute, Children's Hospital of Fudan University, National Children's Medical Center, 399 Wanyuan Road, Shanghai, 201102, China.
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33
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Nano-photoluminescence of natural anyon molecules and topological quantum computation. Sci Rep 2021; 11:21440. [PMID: 34728665 PMCID: PMC8563711 DOI: 10.1038/s41598-021-00859-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 10/18/2021] [Indexed: 11/26/2022] Open
Abstract
The proposal of fault-tolerant quantum computations, which promise to dramatically improve the operation of quantum computers and to accelerate the development of the compact hardware for them, is based on topological quantum field theories, which rely on the existence in Nature of physical systems described by a Lagrangian containing a non-Abelian (NA) topological term. These are solid-state systems having two-dimensional electrons, which are coupled to magnetic-flux-quanta vortexes, forming complex particles, known as anyons. Topological quantum computing (TQC) operations thus represent a physical realization of the mathematical operations involving NA representations of a braid group Bn, generated by a set of n localized anyons, which can be braided and fused using a “tweezer” and controlled by a detector. For most of the potential TQC material systems known so far, which are 2D-electron–gas semiconductor structure at high magnetic field and a variety of hybrid superconductor/topological-material heterostructures, the realization of anyon localization versus tweezing and detecting meets serious obstacles, chief among which are the necessity of using current control, i.e., mobile particles, of the TQC operations and high density electron puddles (containing thousands of electrons) to generate a single vortex. Here we demonstrate a novel system, in which these obstacles can be overcome, and in which vortexes are generated by a single electron. This is a ~ 150 nm size many electron InP/GaInP2 self-organized quantum dot, in which molecules, consisting of a few localized anyons, are naturally formed and exist at zero external magnetic field. We used high-spatial-resolution scanning magneto-photoluminescence spectroscopy measurements of a set of the dots having five and six electrons, together with many-body quantum mechanical calculations to demonstrate spontaneous formation of the anyon magneto-electron particles (eν) having fractional charge ν = n/k, where n = 1–4 and k = 3–15 are the number of electrons and vortexes, respectively, arranged in molecular structures having a built-in (internal) magnetic field of 6–12 T. Using direct imaging of the molecular configurations we observed fusion and braiding of eν-anyons under photo-excitation and revealed the possibility of using charge sensing for their control. Our investigations show that InP/GaInP2 anyon-molecule QDs, which have intrinsic transformations of localized eν-anyons compatible with TQC operations and capable of being probed by charge sensing, are very promising for the realization of TQC.
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34
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Srinivas R, Burd SC, Knaack HM, Sutherland RT, Kwiatkowski A, Glancy S, Knill E, Wineland DJ, Leibfried D, Wilson AC, Allcock DTC, Slichter DH. High-fidelity laser-free universal control of trapped ion qubits. Nature 2021; 597:209-213. [PMID: 34497396 PMCID: PMC11165722 DOI: 10.1038/s41586-021-03809-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 07/07/2021] [Indexed: 11/09/2022]
Abstract
Universal control of multiple qubits-the ability to entangle qubits and to perform arbitrary individual qubit operations1-is a fundamental resource for quantum computing2, simulation3 and networking4. Qubits realized in trapped atomic ions have shown the highest-fidelity two-qubit entangling operations5-7 and single-qubit rotations8 so far. Universal control of trapped ion qubits has been separately demonstrated using tightly focused laser beams9-12 or by moving ions with respect to laser beams13-15, but at lower fidelities. Laser-free entangling methods16-20 may offer improved scalability by harnessing microwave technology developed for wireless communications, but so far their performance has lagged the best reported laser-based approaches. Here we demonstrate high-fidelity laser-free universal control of two trapped-ion qubits by creating both symmetric and antisymmetric maximally entangled states with fidelities of [Formula: see text] and [Formula: see text], respectively (68 per cent confidence level), corrected for initialization error. We use a scheme based on radiofrequency magnetic field gradients combined with microwave magnetic fields that is robust against multiple sources of decoherence and usable with essentially any trapped ion species. The scheme has the potential to perform simultaneous entangling operations on multiple pairs of ions in a large-scale trapped-ion quantum processor without increasing control signal power or complexity. Combining this technology with low-power laser light delivered via trap-integrated photonics21,22 and trap-integrated photon detectors for qubit readout23,24 provides an opportunity for scalable, high-fidelity, fully chip-integrated trapped-ion quantum computing.
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Affiliation(s)
- R Srinivas
- National Institute of Standards and Technology, Boulder, CO, USA.
- Department of Physics, University of Colorado, Boulder, CO, USA.
- Department of Physics, Clarendon Laboratory, University of Oxford, Oxford, UK.
| | - S C Burd
- National Institute of Standards and Technology, Boulder, CO, USA
- Department of Physics, University of Colorado, Boulder, CO, USA
- Department of Physics, Stanford University, Stanford, CA, USA
| | - H M Knaack
- National Institute of Standards and Technology, Boulder, CO, USA
- Department of Physics, University of Colorado, Boulder, CO, USA
| | - R T Sutherland
- Physics Division, Physical and Life Sciences, Lawrence Livermore National Laboratory, Livermore, CA, USA
- Department of Electrical and Computer Engineering, University of Texas at San Antonio, San Antonio, TX, USA
- Department of Physics and Astronomy, University of Texas at San Antonio, San Antonio, TX, USA
| | - A Kwiatkowski
- National Institute of Standards and Technology, Boulder, CO, USA
- Department of Physics, University of Colorado, Boulder, CO, USA
| | - S Glancy
- National Institute of Standards and Technology, Boulder, CO, USA
| | - E Knill
- National Institute of Standards and Technology, Boulder, CO, USA
- Center for Theory of Quantum Matter, University of Colorado, Boulder, CO, USA
| | - D J Wineland
- National Institute of Standards and Technology, Boulder, CO, USA
- Department of Physics, University of Colorado, Boulder, CO, USA
- Department of Physics, University of Oregon, Eugene, OR, USA
| | - D Leibfried
- National Institute of Standards and Technology, Boulder, CO, USA
| | - A C Wilson
- National Institute of Standards and Technology, Boulder, CO, USA
| | - D T C Allcock
- National Institute of Standards and Technology, Boulder, CO, USA
- Department of Physics, University of Colorado, Boulder, CO, USA
- Department of Physics, University of Oregon, Eugene, OR, USA
| | - D H Slichter
- National Institute of Standards and Technology, Boulder, CO, USA.
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35
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D'Onofrio M, Xie Y, Rasmusson AJ, Wolanski E, Cui J, Richerme P. Radial Two-Dimensional Ion Crystals in a Linear Paul Trap. PHYSICAL REVIEW LETTERS 2021; 127:020503. [PMID: 34296899 DOI: 10.1103/physrevlett.127.020503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Accepted: 06/09/2021] [Indexed: 06/13/2023]
Abstract
We experimentally study two-dimensional (2D) Coulomb crystals in the "radial-2D" phase of a linear Paul trap. This phase is identified by a 2D ion lattice aligned entirely with the radial plane and is created by imposing a large ratio of axial to radial trapping potentials. Using arrays of up to 19 ^{171}Yb^{+} ions, we demonstrate that the structural phase boundaries of such crystals are well described by the pseudopotential approximation, despite the time-dependent ion positions driven by intrinsic micromotion. We further observe that micromotion-induced heating of the radial-2D crystal is confined to the radial plane. Finally, we verify that the transverse motional modes, which are used in most ion-trap quantum simulation schemes, are well-predictable numerically and remain decoupled and cold in this geometry. Our results establish radial-2D ion crystals as a robust experimental platform for realizing a variety of theoretical proposals in quantum simulation and computation.
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Affiliation(s)
- Marissa D'Onofrio
- Indiana University Department of Physics, Bloomington, Indiana 47405, USA and Indiana University Quantum Science and Engineering Center, Bloomington, Indiana 47405, USA
| | - Yuanheng Xie
- Indiana University Department of Physics, Bloomington, Indiana 47405, USA and Indiana University Quantum Science and Engineering Center, Bloomington, Indiana 47405, USA
| | - A J Rasmusson
- Indiana University Department of Physics, Bloomington, Indiana 47405, USA and Indiana University Quantum Science and Engineering Center, Bloomington, Indiana 47405, USA
| | - Evangeline Wolanski
- Indiana University Department of Physics, Bloomington, Indiana 47405, USA and Indiana University Quantum Science and Engineering Center, Bloomington, Indiana 47405, USA
| | - Jiafeng Cui
- Indiana University Department of Physics, Bloomington, Indiana 47405, USA and Indiana University Quantum Science and Engineering Center, Bloomington, Indiana 47405, USA
| | - Philip Richerme
- Indiana University Department of Physics, Bloomington, Indiana 47405, USA and Indiana University Quantum Science and Engineering Center, Bloomington, Indiana 47405, USA
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36
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Blümel R, Grzesiak N, Nguyen NH, Green AM, Li M, Maksymov A, Linke NM, Nam Y. Efficient Stabilized Two-Qubit Gates on a Trapped-Ion Quantum Computer. PHYSICAL REVIEW LETTERS 2021; 126:220503. [PMID: 34152167 DOI: 10.1103/physrevlett.126.220503] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 05/04/2021] [Indexed: 06/13/2023]
Abstract
In order to scale up quantum processors and achieve a quantum advantage, it is crucial to economize on the power requirement of two-qubit gates, make them robust to drift in experimental parameters, and shorten the gate times. Applicable to all quantum computer architectures whose two-qubit gates rely on phase-space closure, we present here a new gate-optimizing principle according to which negligible amounts of gate fidelity are traded for substantial savings in power, which, in turn, can be traded for substantial increases in gate speed and/or qubit connectivity. As a concrete example, we illustrate the method by constructing optimal pulses for entangling gates on a pair of ions within a trapped-ion chain, one of the leading quantum computing architectures. Our method is direct, noniterative, and linear, and, in some parameter regimes, constructs gate-steering pulses requiring up to an order of magnitude less power than the standard method. Additionally, our method provides increased robustness to mode drift. We verify the new trade-off principle experimentally on our trapped-ion quantum computer.
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Affiliation(s)
- Reinhold Blümel
- Wesleyan University, Middletown, Connecticut 06459, USA
- IonQ, College Park, Maryland 20740, USA
| | | | - Nhung H Nguyen
- Joint Quantum Institute, University of Maryland, College Park, Maryland 20742, USA
| | - Alaina M Green
- Joint Quantum Institute, University of Maryland, College Park, Maryland 20742, USA
| | - Ming Li
- IonQ, College Park, Maryland 20740, USA
| | | | - Norbert M Linke
- Joint Quantum Institute, University of Maryland, College Park, Maryland 20742, USA
| | - Yunseong Nam
- IonQ, College Park, Maryland 20740, USA
- Joint Quantum Institute, University of Maryland, College Park, Maryland 20742, USA
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38
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de Leon NP, Itoh KM, Kim D, Mehta KK, Northup TE, Paik H, Palmer BS, Samarth N, Sangtawesin S, Steuerman DW. Materials challenges and opportunities for quantum computing hardware. Science 2021; 372:372/6539/eabb2823. [PMID: 33859004 DOI: 10.1126/science.abb2823] [Citation(s) in RCA: 65] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Quantum computing hardware technologies have advanced during the past two decades, with the goal of building systems that can solve problems that are intractable on classical computers. The ability to realize large-scale systems depends on major advances in materials science, materials engineering, and new fabrication techniques. We identify key materials challenges that currently limit progress in five quantum computing hardware platforms, propose how to tackle these problems, and discuss some new areas for exploration. Addressing these materials challenges will require scientists and engineers to work together to create new, interdisciplinary approaches beyond the current boundaries of the quantum computing field.
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Affiliation(s)
- Nathalie P de Leon
- Department of Electrical Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Kohei M Itoh
- School of Fundamental Science and Technology, Keio University, Yokohama 223-8522, Japan
| | - Dohun Kim
- Department of Physics and Astronomy and Institute of Applied Physics, Seoul National University, Seoul 08826, Korea
| | - Karan K Mehta
- Department of Physics, Institute for Quantum Electronics, ETH Zürich, 8092 Zürich, Switzerland
| | - Tracy E Northup
- Institut für Experimentalphysik, Universität Innsbruck, 6020 Innsbruck, Austria
| | - Hanhee Paik
- IBM Quantum, IBM T. J. Watson Research Center, Yorktown Heights, NY 10598, USA.
| | - B S Palmer
- Laboratory for Physical Sciences, University of Maryland, College Park, MD 20740, USA.,Quantum Materials Center, University of Maryland, College Park, MD 20742, USA
| | - N Samarth
- Department of Physics, The Pennsylvania State University, University Park, PA 16802, USA
| | - Sorawis Sangtawesin
- School of Physics and Center of Excellence in Advanced Functional Materials, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand
| | - D W Steuerman
- Kavli Foundation, 5715 Mesmer Avenue, Los Angeles, CA 90230, USA
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39
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Quantum computer based on shuttling trapped ions. Nature 2021; 592:190-191. [PMID: 33828312 DOI: 10.1038/d41586-021-00844-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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40
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Wu W, Zhang T, Chen PX. Quantum computing and simulation with trapped ions: On the path to the future. FUNDAMENTAL RESEARCH 2021. [DOI: 10.1016/j.fmre.2020.12.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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41
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Park Y, Jung C, Seong M, Lee M, Cho DD, Kim T. A New Measurement Method for High Voltages Applied to an Ion Trap Generated by an RF Resonator. SENSORS 2021; 21:s21041143. [PMID: 33562053 PMCID: PMC7914741 DOI: 10.3390/s21041143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 01/18/2021] [Accepted: 02/04/2021] [Indexed: 11/25/2022]
Abstract
A new method is proposed to measure unknown amplitudes of radio frequency (RF) voltages applied to ion traps, using a pre-calibrated voltage divider with RF shielding. In contrast to previous approaches that estimate the applied voltage by comparing the measured secular frequencies with a numerical simulation, we propose using a pre-calibrated voltage divider to determine the absolute amplitude of large RF voltages amplified by a helical resonator. The proposed method does not require measurement of secular frequencies and completely removes uncertainty caused by limitations of numerical simulations. To experimentally demonstrate our method, we first obtained a functional relation between measured secular frequencies and large amplitudes of RF voltages using the calibrated voltage divider. A comparison of measured relations and simulation results without any fitting parameters confirmed the validity of the proposed method. Our method can be applied to most ion trap experiments. In particular, it will be an essential tool for surface ion traps which are extremely vulnerable to unknown large RF voltages and for improving the accuracy of numerical simulations for ion trap experiments.
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Affiliation(s)
- Yunjae Park
- Department of Electrical and Computer Engineering, Seoul National University, Seoul 08826, Korea; (Y.P.); (C.J.); (M.L.); (D.D.C.)
- Automation and Systems Research Institute, Seoul National University, Seoul 08826, Korea
- Inter-University Semiconductor Research Center, Seoul National University, Seoul 08826, Korea
| | - Changhyun Jung
- Department of Electrical and Computer Engineering, Seoul National University, Seoul 08826, Korea; (Y.P.); (C.J.); (M.L.); (D.D.C.)
- Automation and Systems Research Institute, Seoul National University, Seoul 08826, Korea
- Inter-University Semiconductor Research Center, Seoul National University, Seoul 08826, Korea
| | - Myeongseok Seong
- Department of Mechanical Engineering, Seoul National University, Seoul 08826, Korea;
| | - Minjae Lee
- Department of Electrical and Computer Engineering, Seoul National University, Seoul 08826, Korea; (Y.P.); (C.J.); (M.L.); (D.D.C.)
- Automation and Systems Research Institute, Seoul National University, Seoul 08826, Korea
- Inter-University Semiconductor Research Center, Seoul National University, Seoul 08826, Korea
| | - Dongil Dan Cho
- Department of Electrical and Computer Engineering, Seoul National University, Seoul 08826, Korea; (Y.P.); (C.J.); (M.L.); (D.D.C.)
- Automation and Systems Research Institute, Seoul National University, Seoul 08826, Korea
- Inter-University Semiconductor Research Center, Seoul National University, Seoul 08826, Korea
| | - Taehyun Kim
- Automation and Systems Research Institute, Seoul National University, Seoul 08826, Korea
- Inter-University Semiconductor Research Center, Seoul National University, Seoul 08826, Korea
- Department of Computer Science and Engineering, Seoul National University, Seoul 08826, Korea
- Institute of Computer Technology, Seoul National University, Seoul 08826, Korea
- Correspondence: ; Tel.: +82-2-880-1725
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42
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Daiss S, Langenfeld S, Welte S, Distante E, Thomas P, Hartung L, Morin O, Rempe G. A quantum-logic gate between distant quantum-network modules. Science 2021; 371:614-617. [PMID: 33542133 DOI: 10.1126/science.abe3150] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Accepted: 11/20/2020] [Indexed: 11/02/2022]
Abstract
The big challenge in quantum computing is to realize scalable multi-qubit systems with cross-talk-free addressability and efficient coupling of arbitrarily selected qubits. Quantum networks promise a solution by integrating smaller qubit modules to a larger computing cluster. Such a distributed architecture, however, requires the capability to execute quantum-logic gates between distant qubits. Here we experimentally realize such a gate over a distance of 60 meters. We employ an ancillary photon that we successively reflect from two remote qubit modules, followed by a heralding photon detection, which triggers a final qubit rotation. We use the gate for remote entanglement creation of all four Bell states. Our nonlocal quantum-logic gate could be extended both to multiple qubits and many modules for a tailor-made multi-qubit computing register.
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Affiliation(s)
- Severin Daiss
- Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Straße 1, 85748 Garching, Germany.
| | - Stefan Langenfeld
- Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Straße 1, 85748 Garching, Germany
| | - Stephan Welte
- Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Straße 1, 85748 Garching, Germany
| | - Emanuele Distante
- Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Straße 1, 85748 Garching, Germany.,ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Mediterranean Technology Park, 08860 Castelldefels (Barcelona), Spain
| | - Philip Thomas
- Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Straße 1, 85748 Garching, Germany
| | - Lukas Hartung
- Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Straße 1, 85748 Garching, Germany
| | - Olivier Morin
- Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Straße 1, 85748 Garching, Germany
| | - Gerhard Rempe
- Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Straße 1, 85748 Garching, Germany
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43
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Guo Q, Zhao YY, Grassl M, Nie X, Xiang GY, Xin T, Yin ZQ, Zeng B. Testing a quantum error-correcting code on various platforms. Sci Bull (Beijing) 2021; 66:29-35. [PMID: 36654309 DOI: 10.1016/j.scib.2020.07.033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 06/02/2020] [Accepted: 07/20/2020] [Indexed: 01/20/2023]
Abstract
Quantum error correction plays an important role in fault-tolerant quantum information processing. It is usually difficult to experimentally realize quantum error correction, as it requires multiple qubits and quantum gates with high fidelity. Here we propose a simple quantum error-correcting code for the detected amplitude damping channel. The code requires only two qubits. We implement the encoding, the channel, and the recovery on an optical platform, the IBM Q System, and a nuclear magnetic resonance system. For all of these systems, the error correction advantage appears when the damping rate exceeds some threshold. We compare the features of these quantum information processing systems used and demonstrate the advantage of quantum error correction on current quantum computing platforms.
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Affiliation(s)
- Qihao Guo
- Institute for Quantum Computing, Baidu Research, Beijing 100193, China; Department of Applied Physics, Xi'an Jiaotong University, Xi'an 710049, China; Center for Quantum Computing, Peng Cheng Laboratory, Shenzhen 518055, China
| | - Yuan-Yuan Zhao
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China; Center for Quantum Computing, Peng Cheng Laboratory, Shenzhen 518055, China
| | - Markus Grassl
- Max Planck Institute for the Science of Light, 91058 Erlangen, Germany; International Centre for Theory of Quantum Technologies, 80-308 Gdańsk, Poland
| | - Xinfang Nie
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China; Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Guo-Yong Xiang
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China.
| | - Tao Xin
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China; Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China.
| | - Zhang-Qi Yin
- Center for Quantum Technology Research and Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurements (MOE),School of Physics, Beijing Institute of Technology, Beijing 100081, China
| | - Bei Zeng
- Department of Physics, The Hong Kong University of Science and Technology, Hong Kong, China.
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44
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Wang P, Luan CY, Qiao M, Um M, Zhang J, Wang Y, Yuan X, Gu M, Zhang J, Kim K. Single ion qubit with estimated coherence time exceeding one hour. Nat Commun 2021; 12:233. [PMID: 33431845 PMCID: PMC7801401 DOI: 10.1038/s41467-020-20330-w] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 11/24/2020] [Indexed: 11/08/2022] Open
Abstract
Realizing a long coherence time quantum memory is a major challenge of current quantum technology. Until now, the longest coherence-time of a single qubit was reported as 660 s in a single 171Yb+ ion-qubit through the technical developments of sympathetic cooling and dynamical decoupling pulses, which addressed heating-induced detection inefficiency and magnetic field fluctuations. However, it was not clear what prohibited further enhancement. Here, we identify and suppress the limiting factors, which are the remaining magnetic-field fluctuations, frequency instability and leakage of the microwave reference-oscillator. Then, we observe the coherence time of around 5500 s for the 171Yb+ ion-qubit, which is the time constant of the exponential decay fit from the measurements up to 960 s. We also systematically study the decoherence process of the quantum memory by using quantum process tomography and analyze the results by applying recently developed resource theories of quantum memory and coherence. Our experimental demonstration will accelerate practical applications of quantum memories for various quantum information processing, especially in the noisy-intermediate-scale quantum regime.
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Affiliation(s)
- Pengfei Wang
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, 100084, Beijing, China.
| | - Chun-Yang Luan
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, 100084, Beijing, China
| | - Mu Qiao
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, 100084, Beijing, China
| | - Mark Um
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, 100084, Beijing, China
| | - Junhua Zhang
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, 100084, Beijing, China
- Shenzhen Institute for Quantum Science and Engineering, and Department of Physics, Southern University of Science and Technology, 518055, Shenzhen, P. R. China
| | - Ye Wang
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, 100084, Beijing, China
- Department of Electrical and Computer Engineering, Duke University, Durham, NC, 27708, USA
| | - Xiao Yuan
- Stanford Institute for Theoretical Physics, Stanford University, Stanford, CA, 94305, USA
- Center on Frontiers of Computing Studies, Department of Computer Science, Peking University, Beijing, 100871, China
| | - Mile Gu
- Centre for Quantum Technologies, National University of Singapore, Singapore, 117543, Singapore
- School of Mathematical and Physical Sciences, Nanyang Technological University, Singapore, 637371, Singapore
- Complexity Institute, Nanyang Technological University, Singapore, 637335, Singapore
| | - Jingning Zhang
- Beijing Academy of Quantum Information Sciences, 100193, Beijing, China
| | - Kihwan Kim
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, 100084, Beijing, China.
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45
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Bardin JC, Slichter DH, Reilly DJ. Microwaves in Quantum Computing. IEEE JOURNAL OF MICROWAVES 2021; 1:10.1109/JMW.2020.3034071. [PMID: 34355217 PMCID: PMC8335598 DOI: 10.1109/jmw.2020.3034071] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Quantum information processing systems rely on a broad range of microwave technologies and have spurred development of microwave devices and methods in new operating regimes. Here we review the use of microwave signals and systems in quantum computing, with specific reference to three leading quantum computing platforms: trapped atomic ion qubits, spin qubits in semiconductors, and superconducting qubits. We highlight some key results and progress in quantum computing achieved through the use of microwave systems, and discuss how quantum computing applications have pushed the frontiers of microwave technology in some areas. We also describe open microwave engineering challenges for the construction of large-scale, fault-tolerant quantum computers.
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Affiliation(s)
- Joseph C Bardin
- Department of Electrical and Computer Engineering, University of Massachusetts Amherst, Amherst, MA 01003 USA
- Google LLC, Goleta, CA 93117 USA
| | - Daniel H Slichter
- Time and Frequency Division, National Institute of Standards and Technology, Boulder, CO 80305 USA
| | - David J Reilly
- Microsoft Inc., Microsoft Quantum Sydney, The University of Sydney, Sydney, NSW 2050, Australia
- ARC Centre of Excellence for Engineered Quantum Systems (EQuS), School of Physics, The University of Sydney, Sydney, NSW 2050, Australia
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46
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Xu Y, Chu J, Yuan J, Qiu J, Zhou Y, Zhang L, Tan X, Yu Y, Liu S, Li J, Yan F, Yu D. High-Fidelity, High-Scalability Two-Qubit Gate Scheme for Superconducting Qubits. PHYSICAL REVIEW LETTERS 2020; 125:240503. [PMID: 33412065 DOI: 10.1103/physrevlett.125.240503] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Accepted: 10/12/2020] [Indexed: 06/12/2023]
Abstract
High-quality two-qubit gate operations are crucial for scalable quantum information processing. Often, the gate fidelity is compromised when the system becomes more integrated. Therefore, a low-error-rate, easy-to-scale two-qubit gate scheme is highly desirable. Here, we experimentally demonstrate a new two-qubit gate scheme that exploits fixed-frequency qubits and a tunable coupler in a superconducting quantum circuit. The scheme requires less control lines, reduces cross talk effect, and simplifies calibration procedures, yet produces a controlled-Z gate in 30 ns with a high fidelity of 99.5%, derived from the interleaved randomized benchmarking method. Error analysis shows that gate errors are mostly coherence limited. Our demonstration paves the way for large-scale implementation of high-fidelity quantum operations.
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Affiliation(s)
- Yuan Xu
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
- Shenzhen Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
| | - Ji Chu
- National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing, Jiangsu, 210093, China
| | - Jiahao Yuan
- Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
| | - Jiawei Qiu
- Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
| | - Yuxuan Zhou
- Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
| | - Libo Zhang
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
- Shenzhen Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
| | - Xinsheng Tan
- National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing, Jiangsu, 210093, China
| | - Yang Yu
- National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing, Jiangsu, 210093, China
| | - Song Liu
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
- Shenzhen Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
| | - Jian Li
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
- Shenzhen Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
| | - Fei Yan
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
- Shenzhen Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
| | - Dapeng Yu
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
- Shenzhen Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
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47
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Sharma L, Roy A, Panja S, De S. An easy to construct sub-micron resolution imaging system. Sci Rep 2020; 10:21796. [PMID: 33311632 PMCID: PMC7732857 DOI: 10.1038/s41598-020-78509-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 11/20/2020] [Indexed: 11/09/2022] Open
Abstract
We report an easy to construct imaging system that can resolve particles separated by [Formula: see text] 0.68 [Formula: see text]m with minimum aberrations. Its first photon collecting lens is placed at a distance of 31.6 mm giving wide optical access. The microscope has a Numerical Aperture (NA) of 0.33, which is able to collect signal over 0.36 sr. The diffraction limited objective and magnifier recollects 77% photons into the central disc of the image with a transverse spherical aberration of 0.05 mm and magnification upto 238. The system has a depth of field of 142 [Formula: see text]m and a field of view of 56 [Formula: see text]m which images a large ensemble of atoms. The imaging system gives a diffraction limited performance over visible to near-infrared wavelengths on optimization of the working distance and the distance between the objective and magnifier.
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Affiliation(s)
- Lakhi Sharma
- CSIR - National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi, 110012, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - A Roy
- CSIR - National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi, 110012, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India.,Max Planck Institute for the Science of Light, Staudtstrasse 2, Erlangen, 91058, Germany
| | - S Panja
- CSIR - National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi, 110012, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - S De
- Inter-University Centre for Astronomy and Astrophysics (IUCAA), Post Bag 4, Ganeshkhind, Pune, 411007, India.
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48
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Wu X, Tomarken SL, Petersson NA, Martinez LA, Rosen YJ, DuBois JL. High-Fidelity Software-Defined Quantum Logic on a Superconducting Qudit. PHYSICAL REVIEW LETTERS 2020; 125:170502. [PMID: 33156670 DOI: 10.1103/physrevlett.125.170502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 09/14/2020] [Indexed: 06/11/2023]
Abstract
We present an efficient approach to achieving arbitrary, high-fidelity control of a multilevel quantum system using optimal control techniques. As an demonstration, we implement a continuous, software-defined microwave pulse to realize a 0↔2 SWAP gate that achieves an average gate fidelity of 99.4%. We describe our procedure for extracting the system Hamiltonian, calibrating the quantum and classical hardware chain, and evaluating the gate fidelity. Our work represents an alternative, fully generalizable route towards achieving universal quantum control by leveraging optimal control techniques.
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Affiliation(s)
- Xian Wu
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - S L Tomarken
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - N Anders Petersson
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - L A Martinez
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - Yaniv J Rosen
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - Jonathan L DuBois
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
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49
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Ferraro E, De Michielis M. On the robustness of the hybrid qubit computational gates through simulated randomized benchmarking protocols. Sci Rep 2020; 10:17780. [PMID: 33082407 PMCID: PMC7575548 DOI: 10.1038/s41598-020-74817-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 09/28/2020] [Indexed: 11/09/2022] Open
Abstract
One of the main challenges in building a quantum processor is to characterize the environmental noise. Noise characterization can be achieved by exploiting different techniques, such as randomization where several sequences of random quantum gates are applied to the qubit under test to derive statistical characteristics about the affecting noises. A scalable and robust algorithm able to benchmark the full set of Clifford gates using randomization techniques is called randomized benchmarking. In this study, we simulated randomized benchmarking protocols in a semiconducting all-electrical three-electron double-quantum dot qubit, i.e. hybrid qubit, under different error models, that include quasi-static Gaussian and the more realistic 1/f noise model, for the input controls. The average error of specific quantum computational gates is extracted through interleaved randomized benchmarking obtained including Clifford gates between the gate of interest. It provides an estimate of the fidelity as well as theoretical bounds for the average error of the gate under test.
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Affiliation(s)
- Elena Ferraro
- CNR-IMM Agrate Unit, Via C. Olivetti 2, 20864, Agrate Brianza, MB, Italy.
| | - Marco De Michielis
- CNR-IMM Agrate Unit, Via C. Olivetti 2, 20864, Agrate Brianza, MB, Italy.
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50
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Wang Y, Crain S, Fang C, Zhang B, Huang S, Liang Q, Leung PH, Brown KR, Kim J. High-Fidelity Two-Qubit Gates Using a Microelectromechanical-System-Based Beam Steering System for Individual Qubit Addressing. PHYSICAL REVIEW LETTERS 2020; 125:150505. [PMID: 33095613 DOI: 10.1103/physrevlett.125.150505] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 07/17/2020] [Indexed: 06/11/2023]
Abstract
In a large scale trapped atomic ion quantum computer, high-fidelity two-qubit gates need to be extended over all qubits with individual control. We realize and characterize high-fidelity two-qubit gates in a system with up to four ions using radial modes. The ions are individually addressed by two tightly focused beams steered using microelectromechanical system mirrors. We deduce a gate fidelity of 99.49(7)% in a two-ion chain and 99.30(6)% in a four-ion chain by applying a sequence of up to 21 two-qubit gates and measuring the final state fidelity. We characterize the residual errors and discuss methods to further improve the gate fidelity towards values that are compatible with fault-tolerant quantum computation.
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Affiliation(s)
- Ye Wang
- Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708, USA
| | - Stephen Crain
- Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708, USA
| | - Chao Fang
- Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708, USA
| | - Bichen Zhang
- Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708, USA
| | - Shilin Huang
- Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708, USA
| | - Qiyao Liang
- Department of Physics, Duke University, Durham, North Carolina 27708, USA
| | - Pak Hong Leung
- Department of Physics, Duke University, Durham, North Carolina 27708, USA
| | - Kenneth R Brown
- Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708, USA
- Department of Physics, Duke University, Durham, North Carolina 27708, USA
- Department of Chemistry, Duke University, Durham, North Carolina 27708, USA
| | - Jungsang Kim
- Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708, USA
- IonQ, Inc., College Park, Maryland 20740, USA
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