1
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Liles SD, Halverson DJ, Wang Z, Shamim A, Eggli RS, Jin IK, Hillier J, Kumar K, Vorreiter I, Rendell MJ, Huang JY, Escott CC, Hudson FE, Lim WH, Culcer D, Dzurak AS, Hamilton AR. A singlet-triplet hole-spin qubit in MOS silicon. Nat Commun 2024; 15:7690. [PMID: 39227367 PMCID: PMC11372177 DOI: 10.1038/s41467-024-51902-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Accepted: 08/19/2024] [Indexed: 09/05/2024] Open
Abstract
Holes in silicon quantum dots are promising for spin qubit applications due to the strong intrinsic spin-orbit coupling. The spin-orbit coupling produces complex hole-spin dynamics, providing opportunities to further optimise spin qubits. Here, we demonstrate a singlet-triplet qubit using hole states in a planar metal-oxide-semiconductor double quantum dot. We demonstrate rapid qubit control with singlet-triplet oscillations up to 400 MHz. The qubit exhibits promising coherence, with a maximum dephasing time of 600 ns, which is enhanced to 1.3 μs using refocusing techniques. We investigate the magnetic field anisotropy of the eigenstates, and determine a magnetic field orientation to improve the qubit initialisation fidelity. These results present a step forward for spin qubit technology, by implementing a high quality singlet-triplet hole-spin qubit in planar architecture suitable for scaling up to 2D arrays of coupled qubits.
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Affiliation(s)
- S D Liles
- School of Physics, University of New South Wales, Sydney, NSW, 2052, Australia.
| | - D J Halverson
- School of Physics, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Z Wang
- School of Physics, University of New South Wales, Sydney, NSW, 2052, Australia
| | - A Shamim
- School of Physics, University of New South Wales, Sydney, NSW, 2052, Australia
| | - R S Eggli
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056, Basel, Switzerland
| | - I K Jin
- School of Physics, University of New South Wales, Sydney, NSW, 2052, Australia
- Center for Emergent Matter Science, RIKEN, 2-1, Hirosawa, Wako-shi, 351-0198, Saitama, Japan
| | - J Hillier
- School of Physics, University of New South Wales, Sydney, NSW, 2052, Australia
| | - K Kumar
- School of Physics, University of New South Wales, Sydney, NSW, 2052, Australia
| | - I Vorreiter
- School of Physics, University of New South Wales, Sydney, NSW, 2052, Australia
| | - M J Rendell
- School of Physics, University of New South Wales, Sydney, NSW, 2052, Australia
| | - J Y Huang
- School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, NSW, 2052, Australia
- Diraq, Sydney, NSW, Australia
| | - C C Escott
- School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, NSW, 2052, Australia
- Diraq, Sydney, NSW, Australia
| | - F E Hudson
- School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, NSW, 2052, Australia
- Diraq, Sydney, NSW, Australia
| | - W H Lim
- School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, NSW, 2052, Australia
- Diraq, Sydney, NSW, Australia
| | - D Culcer
- School of Physics, University of New South Wales, Sydney, NSW, 2052, Australia
| | - A S Dzurak
- School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, NSW, 2052, Australia
- Diraq, Sydney, NSW, Australia
| | - A R Hamilton
- School of Physics, University of New South Wales, Sydney, NSW, 2052, Australia
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2
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Ivanov SS, Torosov BT, Vitanov NV. High-Fidelity Quantum Control by Polychromatic Pulse Trains. PHYSICAL REVIEW LETTERS 2022; 129:240505. [PMID: 36563260 DOI: 10.1103/physrevlett.129.240505] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 11/08/2022] [Indexed: 06/17/2023]
Abstract
We introduce a quantum control technique using polychromatic pulse trains, consisting of pulses with different carrier frequencies, i.e., different detunings with respect to the qubit transition frequency. We derive numerous polychromatic pulse trains, which generate broadband, narrowband, and passband excitation profiles for different target transition probabilities. This makes it possible to create high-fidelity excitation profiles which are either (i) robust to deviations in the experimental parameters, which is attractive for quantum computing, or (ii) more sensitive to such variations, which is attractive for crosstalk elimination and quantum sensing. The method is demonstrated experimentally using one of IBM's superconducting quantum processors, in a very good agreement between theory and experiment. These results demonstrate both the excellent coherence properties of the IBM qubits and the accuracy, robustness, and flexibility of the proposed quantum control technique. They also show that the detuning is a control parameter which is as efficient as the pulse phase that is commonly used in composite pulses. Hence the method opens a variety of perspectives for quantum control in areas where phase manipulation is difficult or inaccurate.
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Affiliation(s)
- Svetoslav S Ivanov
- Department of Physics, St Kliment Ohridski University of Sofia, 5 James Bourchier Boulevard, 1164 Sofia, Bulgaria
| | - Boyan T Torosov
- Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tsarigradsko chaussée, 1784 Sofia, Bulgaria
| | - Nikolay V Vitanov
- Department of Physics, St Kliment Ohridski University of Sofia, 5 James Bourchier Boulevard, 1164 Sofia, Bulgaria
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3
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Xu H, Song XK, Wang D, Ye L. Robust coherent control in three-level quantum systems using composite pulses. OPTICS EXPRESS 2022; 30:3125-3137. [PMID: 35209438 DOI: 10.1364/oe.449426] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 01/05/2022] [Indexed: 06/14/2023]
Abstract
Here, we focus on using composite pulses to realize high-robustness and high-fidelity coherent control in three-level quantum systems. We design the dynamic parameters (Rabi frequency and detuning) for three-level Hamiltonians for high-fidelity quantum state control using five well-known coherent control techniques including a composite adiabatic passage (CAP). Furthermore, we compare their performance against the Rabi frequency and systematic errors, and accordingly show that the CAP is the most robust against them. It features a broad range of high efficiencies above 99.9%. Thus, it provides an accurate approach for manipulating the evolution of quantum states in three-level quantum systems.
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4
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Touil A, Deffner S. Environment-Assisted Shortcuts to Adiabaticity. ENTROPY (BASEL, SWITZERLAND) 2021; 23:1479. [PMID: 34828177 PMCID: PMC8624449 DOI: 10.3390/e23111479] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Revised: 11/04/2021] [Accepted: 11/05/2021] [Indexed: 11/23/2022]
Abstract
Envariance is a symmetry exhibited by correlated quantum systems. Inspired by this "quantum fact of life," we propose a novel method for shortcuts to adiabaticity, which enables the system to evolve through the adiabatic manifold at all times, solely by controlling the environment. As the main results, we construct the unique form of the driving on the environment that enables such dynamics, for a family of composite states of arbitrary dimension. We compare the cost of this environment-assisted technique with that of counterdiabatic driving, and we illustrate our results for a two-qubit model.
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Affiliation(s)
- Akram Touil
- Department of Physics, University of Maryland, Baltimore County, Baltimore, MD 21250, USA;
| | - Sebastian Deffner
- Department of Physics, University of Maryland, Baltimore County, Baltimore, MD 21250, USA;
- Instituto de Física ‘Gleb Wataghin’, Universidade Estadual de Campinas, Campinas, São Paulo 13083-859, Brazil
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5
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Jirovec D, Hofmann A, Ballabio A, Mutter PM, Tavani G, Botifoll M, Crippa A, Kukucka J, Sagi O, Martins F, Saez-Mollejo J, Prieto I, Borovkov M, Arbiol J, Chrastina D, Isella G, Katsaros G. A singlet-triplet hole spin qubit in planar Ge. NATURE MATERIALS 2021; 20:1106-1112. [PMID: 34083775 DOI: 10.1038/s41563-021-01022-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 04/23/2021] [Indexed: 06/12/2023]
Abstract
Spin qubits are considered to be among the most promising candidates for building a quantum processor. Group IV hole spin qubits are particularly interesting owing to their ease of operation and compatibility with Si technology. In addition, Ge offers the option for monolithic superconductor-semiconductor integration. Here, we demonstrate a hole spin qubit operating at fields below 10 mT, the critical field of Al, by exploiting the large out-of-plane hole g-factors in planar Ge and by encoding the qubit into the singlet-triplet states of a double quantum dot. We observe electrically controlled g-factor difference-driven and exchange-driven rotations with tunable frequencies exceeding 100 MHz and dephasing times of 1 μs, which we extend beyond 150 μs using echo techniques. These results demonstrate that Ge hole singlet-triplet qubits are competing with state-of-the-art GaAs and Si singlet-triplet qubits. In addition, their rotation frequencies and coherence are comparable with those of Ge single spin qubits, but singlet-triplet qubits can be operated at much lower fields, emphasizing their potential for on-chip integration with superconducting technologies.
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Affiliation(s)
- Daniel Jirovec
- Institute of Science and Technology Austria, Klosterneuburg, Austria.
| | - Andrea Hofmann
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Andrea Ballabio
- Laboratory for Epitaxial Nanostructures on Silicon and Spintronics, Physics Department, Politecnico di Milano, Como, Italy
| | - Philipp M Mutter
- Department of Physics, University of Konstanz, Konstanz, Germany
| | - Giulio Tavani
- Laboratory for Epitaxial Nanostructures on Silicon and Spintronics, Physics Department, Politecnico di Milano, Como, Italy
| | - Marc Botifoll
- Catalan Institute of Nanoscience and Nanotechnology, Spanish National Research Council, Barcelona Institute of Science and Technology, Autonomous University of Barcelona, Barcelona, Spain
| | - Alessandro Crippa
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Josip Kukucka
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Oliver Sagi
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Frederico Martins
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | | | - Ivan Prieto
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Maksim Borovkov
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Jordi Arbiol
- Catalan Institute of Nanoscience and Nanotechnology, Spanish National Research Council, Barcelona Institute of Science and Technology, Autonomous University of Barcelona, Barcelona, Spain
- Catalan Institution for Research and Advanced Studies, Barcelona, Spain
| | - Daniel Chrastina
- Laboratory for Epitaxial Nanostructures on Silicon and Spintronics, Physics Department, Politecnico di Milano, Como, Italy
| | - Giovanni Isella
- Laboratory for Epitaxial Nanostructures on Silicon and Spintronics, Physics Department, Politecnico di Milano, Como, Italy
| | - Georgios Katsaros
- Institute of Science and Technology Austria, Klosterneuburg, Austria.
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6
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Gong B, Tu T, Zhu XY, Guo AL, Zhou ZQ, Guo GC, Li CF. A noise-resisted scheme of dynamical decoupling pulses for quantum memories. Sci Rep 2020; 10:15089. [PMID: 32934301 PMCID: PMC7494898 DOI: 10.1038/s41598-020-72071-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 08/25/2020] [Indexed: 11/30/2022] Open
Abstract
Stable quantum memories that capable of storing quantum information for long time scales are an essential building block for an array of potential applications. The long memory time are usually achieved via dynamical decoupling technique involving decoupling of the memory states from its local environment. However, because this process is strongly limited by the errors in the pulses, an noise-protected scheme remains challenging in the field of quantum memories. Here we propose a scheme to design a noise-resisted [Formula: see text] pulse, which features high fidelity exceeding [Formula: see text] under realistic situations. Using this [Formula: see text] pulse we can generate different dynamical decoupling sequences that preserve high fidelity for long time scales. The versatility, robustness, and potential scalability of this method may allow for various applications in quantum memories technology.
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Affiliation(s)
- Bo Gong
- Key Laboratory of Quantum Information, University of Science and Technology of China, Chinese Academy of Sciences, Hefei, 230026, People's Republic of China.
| | - Tao Tu
- Key Laboratory of Quantum Information, University of Science and Technology of China, Chinese Academy of Sciences, Hefei, 230026, People's Republic of China.
- Department of Physics and Astronomy, University of California at Los Angeles, Los Angeles, CA, 90095, USA.
| | - Xing-Yu Zhu
- Key Laboratory of Quantum Information, University of Science and Technology of China, Chinese Academy of Sciences, Hefei, 230026, People's Republic of China
- Department of Physics and Astronomy, University of California at Los Angeles, Los Angeles, CA, 90095, USA
| | - Ao-Lin Guo
- Key Laboratory of Quantum Information, University of Science and Technology of China, Chinese Academy of Sciences, Hefei, 230026, People's Republic of China
- Department of Physics and Astronomy, University of California at Los Angeles, Los Angeles, CA, 90095, USA
| | - Zong-Quan Zhou
- Key Laboratory of Quantum Information, University of Science and Technology of China, Chinese Academy of Sciences, Hefei, 230026, People's Republic of China
| | - Guang-Can Guo
- Key Laboratory of Quantum Information, University of Science and Technology of China, Chinese Academy of Sciences, Hefei, 230026, People's Republic of China
| | - Chuan-Feng Li
- Key Laboratory of Quantum Information, University of Science and Technology of China, Chinese Academy of Sciences, Hefei, 230026, People's Republic of China
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7
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Hassanzadeh P. Towards the quantum-enabled technologies for development of drugs or delivery systems. J Control Release 2020; 324:260-279. [DOI: 10.1016/j.jconrel.2020.04.050] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Revised: 04/28/2020] [Accepted: 04/29/2020] [Indexed: 12/20/2022]
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8
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Abstract
Among the different platforms for quantum information processing, individual electron spins in semiconductor quantum dots stand out for their long coherence times and potential for scalable fabrication. The past years have witnessed substantial progress in the capabilities of spin qubits. However, coupling between distant electron spins, which is required for quantum error correction, presents a challenge, and this goal remains the focus of intense research. Quantum teleportation is a canonical method to transmit qubit states, but it has not been implemented in quantum-dot spin qubits. Here, we present evidence for quantum teleportation of electron spin qubits in semiconductor quantum dots. Although we have not performed quantum state tomography to definitively assess the teleportation fidelity, our data are consistent with conditional teleportation of spin eigenstates, entanglement swapping, and gate teleportation. Such evidence for all-matter spin-state teleportation underscores the capabilities of exchange-coupled spin qubits for quantum-information transfer. Despite recent demonstrations of coherent spin-state transfer in arrays of spin qubits via exchange interaction, all-matter spin-state teleportation is still out of reach. Here the authors provide evidence for conditional teleportation of quantum-dot spin states, entanglement swapping, and gate teleportation.
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9
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Coherent spin-state transfer via Heisenberg exchange. Nature 2019; 573:553-557. [PMID: 31554982 DOI: 10.1038/s41586-019-1566-8] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 07/11/2019] [Indexed: 11/09/2022]
Abstract
Quantum information science has the potential to revolutionize modern technology by providing resource-efficient approaches to computing1, communication2 and sensing3. Although the physical qubits in a realistic quantum device will inevitably suffer errors, quantum error correction creates a path to fault-tolerant quantum information processing4. Quantum error correction, however, requires that individual qubits can interact with many other qubits in the processor. Engineering such high connectivity can pose a challenge for platforms such as electron spin qubits5, which naturally favour linear arrays. Here we present an experimental demonstration of the transmission of electron spin states via the Heisenberg exchange interaction in an array of spin qubits. Heisenberg exchange coupling-a direct manifestation of the Pauli exclusion principle, which prevents any two electrons with the same spin state from occupying the same orbital-tends to swap the spin states of neighbouring electrons. By precisely controlling the wavefunction overlap between electrons in a semiconductor quadruple quantum dot array, we generate a series of coherent SWAP operations to transfer both single-spin and entangled states back and forth in the array without moving any electrons. Because the process is scalable to large numbers of qubits, state transfer through Heisenberg exchange will be useful for multi-qubit gates and error correction in spin-based quantum computers.
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10
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Liu BJ, Song XK, Xue ZY, Wang X, Yung MH. Plug-and-Play Approach to Nonadiabatic Geometric Quantum Gates. PHYSICAL REVIEW LETTERS 2019; 123:100501. [PMID: 31573289 DOI: 10.1103/physrevlett.123.100501] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 05/08/2019] [Indexed: 06/10/2023]
Abstract
Nonadiabatic holonomic quantum computation (NHQC) has been developed to shorten the construction times of geometric quantum gates. However, previous NHQC gates require the driving Hamiltonian to satisfy a set of rather restrictive conditions, reducing the robustness of the resulting geometric gates against control errors. Here we show that nonadiabatic geometric gates can be constructed in an extensible way, called NHQC+, for maintaining both flexibility and robustness against certain types of noises. Consequently, this approach makes it possible to incorporate most of the existing optimal control methods, such as dynamical decoupling, composite pulses, and a shortcut to adiabaticity, into the construction of single-looped geometric gates. Furthermore, this extensible approach of geometric quantum computation can be applied to various physical platforms such as superconducting qubits and nitrogen-vacancy centers. Specifically, we performed numerical simulation to show how the noise robustness in recent experimental implementations [Phys. Rev. Lett. 119, 140503 (2017)PRLTAO0031-900710.1103/PhysRevLett.119.140503; Nat. Photonics 11, 309 (2017)NPAHBY1749-488510.1038/nphoton.2017.40] can be significantly improved by our NHQC+.approach. These results cover a large class of new techniques combing the noise robustness of both geometric phase and optimal control theory.
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Affiliation(s)
- Bao-Jie Liu
- Institute for Quantum Science and Engineering, and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Xue-Ke Song
- Institute for Quantum Science and Engineering, and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Zheng-Yuan Xue
- 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 Engineering and Quantum Materials, GPETR Center for Quantum Precision Measurement, and SPTE, South China Normal University, Guangzhou 510006, China
| | - Xin Wang
- Department of Physics, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China, and City University of Hong Kong Shenzhen Research Institute, Shenzhen, Guangdong 518057, China
| | - Man-Hong Yung
- Institute for Quantum Science and Engineering, and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
- Shenzhen Key Laboratory of Quantum Science and Engineering, Shenzhen 518055, China
- Central Research Institute, Huawei Technologies, Shenzhen 518129, China
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11
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A two-qubit gate between phosphorus donor electrons in silicon. Nature 2019; 571:371-375. [DOI: 10.1038/s41586-019-1381-2] [Citation(s) in RCA: 151] [Impact Index Per Article: 30.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Accepted: 05/28/2019] [Indexed: 11/08/2022]
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12
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Zhao X, Hu X. Toward high-fidelity coherent electron spin transport in a GaAs double quantum dot. Sci Rep 2018; 8:13968. [PMID: 30228299 PMCID: PMC6143546 DOI: 10.1038/s41598-018-31879-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 08/14/2018] [Indexed: 11/18/2022] Open
Abstract
In this paper, we investigate how to achieve high-fidelity electron spin transport in a GaAs double quantum dot. Our study examines fidelity loss in spin transport from multiple perspectives. We first study incoherent fidelity loss due to hyperfine and spin-orbit interaction. We calculate fidelity loss due to the random Overhauser field from hyperfine interaction, and spin relaxation rate due to spin-orbit interaction in a wide range of experimental parameters with a focus on the occurrence of spin hot spots. A safe parameter regime is identified in order to avoid these spin hot spots. We then analyze systematic errors due to non-adiabatic transitions in the Landau-Zener process of sweeping the interdot detuning, and propose a scheme to take advantage of possible Landau-Zener-Stückelberg interference to achieve high-fidelity spin transport at a higher speed. At last, we study another systematic error caused by the correction to the electron g-factor from the double dot potential, which can lead to a notable phase error. In all, our results should provide a useful guidance for future experiments on coherent electron spin transport.
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Affiliation(s)
- Xinyu Zhao
- Department of Physics, University at Buffalo, SUNY, Buffalo, New York, 14260-1500, USA
| | - Xuedong Hu
- Department of Physics, University at Buffalo, SUNY, Buffalo, New York, 14260-1500, USA.
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13
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Martins F, Malinowski FK, Nissen PD, Fallahi S, Gardner GC, Manfra MJ, Marcus CM, Kuemmeth F. Negative Spin Exchange in a Multielectron Quantum Dot. PHYSICAL REVIEW LETTERS 2017; 119:227701. [PMID: 29286778 DOI: 10.1103/physrevlett.119.227701] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2017] [Indexed: 06/07/2023]
Abstract
We use a one-electron quantum dot as a spectroscopic probe to study the spin properties of a gate-controlled multielectron GaAs quantum dot at the transition between odd and even occupation numbers. We observe that the multielectron ground-state transitions from spin-1/2-like to singletlike to tripletlike as we increase the detuning towards the next higher charge state. The sign reversal in the inferred exchange energy persists at zero magnetic field, and the exchange strength is tunable by gate voltages and in-plane magnetic fields. Complementing spin leakage spectroscopy data, the inspection of coherent multielectron spin exchange oscillations provides further evidence for the sign reversal and, inferentially, for the importance of nontrivial multielectron spin exchange correlations.
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Affiliation(s)
- Frederico Martins
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Filip K Malinowski
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Peter D Nissen
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Saeed Fallahi
- Department of Physics and Astronomy, Station Q Purdue, and Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, USA
| | - Geoffrey C Gardner
- Department of Physics and Astronomy, Station Q Purdue, and Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, USA
| | - Michael J Manfra
- Department of Physics and Astronomy, Station Q Purdue, and Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, USA
- School of Electrical and Computer Engineering and School of Materials Engineering, Purdue University, West Lafayette, Indiana 47907, USA
| | - Charles M Marcus
- Center for Quantum Devices and Station Q Copenhagen, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Ferdinand Kuemmeth
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
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14
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Friesen M, Ghosh J, Eriksson MA, Coppersmith SN. A decoherence-free subspace in a charge quadrupole qubit. Nat Commun 2017; 8:15923. [PMID: 28643778 PMCID: PMC5490009 DOI: 10.1038/ncomms15923] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Accepted: 05/15/2017] [Indexed: 12/03/2022] Open
Abstract
Quantum computing promises significant speed-up for certain types of computational problems. However, robust implementations of semiconducting qubits must overcome the effects of charge noise that currently limit coherence during gate operations. Here we describe a scheme for protecting solid-state qubits from uniform electric field fluctuations by generalizing the concept of a decoherence-free subspace for spins, and we propose a specific physical implementation: a quadrupole charge qubit formed in a triple quantum dot. The unique design of the quadrupole qubit enables a particularly simple pulse sequence for suppressing the effects of noise during gate operations. Simulations yield gate fidelities 10-1,000 times better than traditional charge qubits, depending on the magnitude of the environmental noise. Our results suggest that any qubit scheme employing Coulomb interactions (for example, encoded spin qubits or two-qubit gates) could benefit from such a quadrupolar design.
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Affiliation(s)
- Mark Friesen
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Joydip Ghosh
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - M. A. Eriksson
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - S. N. Coppersmith
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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15
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Geng J, Wu Y, Wang X, Xu K, Shi F, Xie Y, Rong X, Du J. Experimental Time-Optimal Universal Control of Spin Qubits in Solids. PHYSICAL REVIEW LETTERS 2016; 117:170501. [PMID: 27824462 DOI: 10.1103/physrevlett.117.170501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Indexed: 06/06/2023]
Abstract
Quantum control of systems plays an important role in modern science and technology. The ultimate goal of quantum control is to achieve high-fidelity universal control in a time-optimal way. Although high-fidelity universal control has been reported in various quantum systems, experimental implementation of time-optimal universal control remains elusive. Here, we report the experimental realization of time-optimal universal control of spin qubits in diamond. By generalizing a recent method for solving quantum brachistochrone equations [X. Wang et al., Phys. Rev. Lett. 114, 170501 (2015)], we obtained accurate minimum-time protocols for multiple qubits with fixed qubit interactions and a constrained control field. Single- and two-qubit time-optimal gates are experimentally implemented with fidelities of 99% obtained via quantum process tomography. Our work provides a time-optimal route to achieve accurate quantum control and unlocks new capabilities for the emerging field of time-optimal control in general quantum systems.
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Affiliation(s)
- Jianpei Geng
- CAS Key Laboratory of Microscale Magnetic Resonance and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
| | - Yang Wu
- CAS Key Laboratory of Microscale Magnetic Resonance and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
| | - Xiaoting Wang
- Hearne Institute for Theoretical Physics, Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803, USA
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Kebiao Xu
- CAS Key Laboratory of Microscale Magnetic Resonance and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
| | - Fazhan Shi
- CAS Key Laboratory of Microscale Magnetic Resonance and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
- Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
| | - Yijin Xie
- CAS Key Laboratory of Microscale Magnetic Resonance and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
| | - Xing Rong
- CAS Key Laboratory of Microscale Magnetic Resonance and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
- Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
| | - Jiangfeng Du
- CAS Key Laboratory of Microscale Magnetic Resonance and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
- Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
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16
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Noise filtering of composite pulses for singlet-triplet qubits. Sci Rep 2016; 6:28996. [PMID: 27383129 PMCID: PMC4935950 DOI: 10.1038/srep28996] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 06/13/2016] [Indexed: 11/18/2022] Open
Abstract
Semiconductor quantum dot spin qubits are promising candidates for quantum computing. In these systems, the dynamically corrected gates offer considerable reduction of gate errors and are therefore of great interest both theoretically and experimentally. They are, however, designed under the static-noise model and may be considered as low-frequency filters. In this work, we perform a comprehensive theoretical study of the response of a type of dynamically corrected gates, namely the supcode for singlet-triplet qubits, to realistic 1/f noises with frequency spectra 1/ωα. Through randomized benchmarking, we have found that supcode offers improvement of the gate fidelity for α 1 and the improvement becomes exponentially more pronounced with the increase of the noise exponent in the range 1 α ≤ 3 studied. On the other hand, for small α, supcode will not offer any improvement. The δJ-supcode, specifically designed for systems where the nuclear noise is absent, is found to offer additional error reduction than the full supcode for charge noises. The computed filter transfer functions of the supcode gates are also presented.
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17
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Semiconductor-inspired design principles for superconducting quantum computing. Nat Commun 2016; 7:11059. [PMID: 26983379 PMCID: PMC4800439 DOI: 10.1038/ncomms11059] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Accepted: 02/16/2016] [Indexed: 11/25/2022] Open
Abstract
Superconducting circuits offer tremendous design flexibility in the quantum regime culminating most recently in the demonstration of few qubit systems supposedly approaching the threshold for fault-tolerant quantum information processing. Competition in the solid-state comes from semiconductor qubits, where nature has bestowed some very useful properties which can be utilized for spin qubit-based quantum computing. Here we begin to explore how selective design principles deduced from spin-based systems could be used to advance superconducting qubit science. We take an initial step along this path proposing an encoded qubit approach realizable with state-of-the-art tunable Josephson junction qubits. Our results show that this design philosophy holds promise, enables microwave-free control, and offers a pathway to future qubit designs with new capabilities such as with higher fidelity or, perhaps, operation at higher temperature. The approach is also especially suited to qubits on the basis of variable super-semi junctions. Superconducting circuits offer great promise for quantum computing, but implementations require careful shielding from control electronics. Here, the authors take inspirations from semiconductor spin-based qubits to design Josephson junctions quantum circuits whose qubits do not require microwave control.
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18
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Rong X, Geng J, Shi F, Liu Y, Xu K, Ma W, Kong F, Jiang Z, Wu Y, Du J. Experimental fault-tolerant universal quantum gates with solid-state spins under ambient conditions. Nat Commun 2015; 6:8748. [PMID: 26602456 PMCID: PMC4674779 DOI: 10.1038/ncomms9748] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 09/28/2015] [Indexed: 12/18/2022] Open
Abstract
Quantum computation provides great speedup over its classical counterpart for certain problems. One of the key challenges for quantum computation is to realize precise control of the quantum system in the presence of noise. Control of the spin-qubits in solids with the accuracy required by fault-tolerant quantum computation under ambient conditions remains elusive. Here, we quantitatively characterize the source of noise during quantum gate operation and demonstrate strategies to suppress the effect of these. A universal set of logic gates in a nitrogen-vacancy centre in diamond are reported with an average single-qubit gate fidelity of 0.999952 and two-qubit gate fidelity of 0.992. These high control fidelities have been achieved at room temperature in naturally abundant 13C diamond via composite pulses and an optimized control method. High fidelity manipulation of diamond-based spin qubits is difficult at room temperature because of decoherence. Here, the authors show a universal set of logic gates in nitrogen-vacancy centres with average single-qubit and two-qubit gate fidelities of 0.999952 and 0.992, respectively.
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Affiliation(s)
- Xing Rong
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China.,Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China.,Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
| | - Jianpei Geng
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China.,Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
| | - Fazhan Shi
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China.,Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China.,Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
| | - Ying Liu
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China.,Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
| | - Kebiao Xu
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China.,Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
| | - Wenchao Ma
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China.,Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
| | - Fei Kong
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China.,Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
| | - Zhen Jiang
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China.,Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
| | - Yang Wu
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China.,Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
| | - Jiangfeng Du
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China.,Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China.,Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
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19
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Barnes E, Wang X, Das Sarma S. Robust quantum control using smooth pulses and topological winding. Sci Rep 2015; 5:12685. [PMID: 26239195 PMCID: PMC4523836 DOI: 10.1038/srep12685] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 07/06/2015] [Indexed: 11/09/2022] Open
Abstract
The greatest challenge in achieving the high level of control needed for future technologies based on coherent quantum systems is the decoherence induced by the environment. Here, we present an analytical approach that yields explicit constraints on the driving field which are necessary and sufficient to ensure that the leading-order noise-induced errors in a qubit's evolution cancel exactly. We derive constraints for two of the most common types of noise that arise in qubits: slow fluctuations of the qubit energy splitting and fluctuations in the driving field itself. By theoretically recasting a phase in the qubit's wavefunction as a topological winding number, we can satisfy the noise-cancelation conditions by adjusting driving field parameters without altering the target state or quantum evolution. We demonstrate our method by constructing robust quantum gates for two types of spin qubit: phosphorous donors in silicon and nitrogen-vacancy centers in diamond.
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Affiliation(s)
- Edwin Barnes
- Condensed Matter Theory Center, Department of Physics, University of Maryland, College Park, MD 20742, USA
- Joint Quantum Institute, University of Maryland, College Park, MD 20742, USA
| | - Xin Wang
- Department of Physics and Materials Science, City University of Hong Kong, Kowloon, Hong Kong SAR, China
| | - S. Das Sarma
- Condensed Matter Theory Center, Department of Physics, University of Maryland, College Park, MD 20742, USA
- Joint Quantum Institute, University of Maryland, College Park, MD 20742, USA
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20
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Rong X, Geng J, Wang Z, Zhang Q, Ju C, Shi F, Duan CK, Du J. Implementation of dynamically corrected gates on a single electron spin in diamond. PHYSICAL REVIEW LETTERS 2014; 112:050503. [PMID: 24580578 DOI: 10.1103/physrevlett.112.050503] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Indexed: 06/03/2023]
Abstract
Precise control of an open quantum system is critical to quantum information processing but is challenging due to inevitable interactions between the quantum system and the environment. We demonstrated experimentally a type of dynamically corrected gates using only bounded-strength pulses on the nitrogen-vacancy centers in diamond. The infidelity of quantum gates caused by a nuclear-spin bath is reduced from being the second order to the sixth order of the noise-to-control-field ratio, which offers greater efficiency in reducing infidelity. The quantum gates have been protected to the limit essentially set by the spin-lattice relaxation time T1. Our work marks an important step towards fault-tolerant quantum computation in realistic systems.
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Affiliation(s)
- Xing Rong
- Hefei National Laboratory for Physics Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Jianpei Geng
- Hefei National Laboratory for Physics Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
| | - Zixiang Wang
- Hefei National Laboratory for Physics Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
| | - Qi Zhang
- Hefei National Laboratory for Physics Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
| | - Chenyong Ju
- Hefei National Laboratory for Physics Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Fazhan Shi
- Hefei National Laboratory for Physics Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Chang-Kui Duan
- Hefei National Laboratory for Physics Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Jiangfeng Du
- Hefei National Laboratory for Physics Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
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21
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Abstract
Several logical qubits and quantum gates have been proposed for semiconductor quantum dots controlled by voltages applied to top gates. The different schemes can be difficult to compare meaningfully. Here we develop a theoretical framework to evaluate disparate qubit-gating schemes on an equal footing. We apply the procedure to two types of double-dot qubits: the singlet-triplet and the semiconducting quantum dot hybrid qubit. We investigate three quantum gates that flip the qubit state: a DC pulsed gate, an AC gate based on logical qubit resonance, and a gate-like process known as stimulated Raman adiabatic passage. These gates are all mediated by an exchange interaction that is controlled experimentally using the interdot tunnel coupling g and the detuning [Symbol: see text], which sets the energy difference between the dots. Our procedure has two steps. First, we optimize the gate fidelity (f) for fixed g as a function of the other control parameters; this yields an f(opt)(g) that is universal for different types of gates. Next, we identify physical constraints on the control parameters; this yields an upper bound f(max) that is specific to the qubit-gate combination. We show that similar gate fidelities (~99:5%) should be attainable for singlet-triplet qubits in isotopically purified Si, and for hybrid qubits in natural Si. Considerably lower fidelities are obtained for GaAs devices, due to the fluctuating magnetic fields ΔB produced by nuclear spins.
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22
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De Greve K, Press D, McMahon PL, Yamamoto Y. Ultrafast optical control of individual quantum dot spin qubits. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2013; 76:092501. [PMID: 24006335 DOI: 10.1088/0034-4885/76/9/092501] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Single spins in semiconductor quantum dots form a promising platform for solid-state quantum information processing. The spin-up and spin-down states of a single electron or hole, trapped inside a quantum dot, can represent a single qubit with a reasonably long decoherence time. The spin qubit can be optically coupled to excited (charged exciton) states that are also trapped in the quantum dot, which provides a mechanism to quickly initialize, manipulate and measure the spin state with optical pulses, and to interface between a stationary matter qubit and a 'flying' photonic qubit for quantum communication and distributed quantum information processing. The interaction of the spin qubit with light may be enhanced by placing the quantum dot inside a monolithic microcavity. An entire system, consisting of a two-dimensional array of quantum dots and a planar microcavity, may plausibly be constructed by modern semiconductor nano-fabrication technology and could offer a path toward chip-sized scalable quantum repeaters and quantum computers. This article reviews the recent experimental developments in optical control of single quantum dot spins for quantum information processing. We highlight demonstrations of a complete set of all-optical single-qubit operations on a single quantum dot spin: initialization, an arbitrary SU(2) gate, and measurement. We review the decoherence and dephasing mechanisms due to hyperfine interaction with the nuclear-spin bath, and show how the single-qubit operations can be combined to perform spin echo sequences that extend the qubit decoherence from a few nanoseconds to several microseconds, more than 5 orders of magnitude longer than the single-qubit gate time. Two-qubit coupling is discussed, both within a single chip by means of exchange coupling of nearby spins and optically induced geometric phases, as well as over longer-distances. Long-distance spin-spin entanglement can be generated if each spin can emit a photon that is entangled with the spin, and these photons are then interfered. We review recent work demonstrating entanglement between a stationary spin qubit and a flying photonic qubit. These experiments utilize the polarization- and frequency-dependent spontaneous emission from the lowest charged exciton state to single spin Zeeman sublevels.
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23
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Daems D, Ruschhaupt A, Sugny D, Guérin S. Robust quantum control by a single-shot shaped pulse. PHYSICAL REVIEW LETTERS 2013; 111:050404. [PMID: 23952372 DOI: 10.1103/physrevlett.111.050404] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Indexed: 06/02/2023]
Abstract
Considering the problem of the control of a two-state quantum system by an external field, we establish a general and versatile method allowing the derivation of smooth pulses which feature the properties of high fidelity, robustness, and low area. Such shaped pulses can be interpreted as a single-shot generalization of the composite pulse-sequence technique with a time-dependent phase.
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Affiliation(s)
- D Daems
- Laboratoire Interdisciplinaire Carnot de Bourgogne, CNRS UMR 6303, Université de Bourgogne, BP 47870, 21078 Dijon, France
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24
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Kestner JP, Wang X, Bishop LS, Barnes E, Das Sarma S. Noise-resistant control for a spin qubit array. PHYSICAL REVIEW LETTERS 2013; 110:140502. [PMID: 25166970 DOI: 10.1103/physrevlett.110.140502] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Indexed: 06/03/2023]
Abstract
We develop a systematic method of performing corrected gate operations on an array of exchange-coupled singlet-triplet qubits in the presence of both fluctuating nuclear Overhauser field gradients and charge noise. The single-qubit control sequences we present have a simple form, are relatively short, and form the building blocks of a corrected cnot gate when also implemented on the interqubit exchange link. This is a key step towards enabling large-scale quantum computation in a semiconductor-based architecture by facilitating error reduction below the quantum error correction threshold for both single-qubit and multiqubit gate operations.
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Affiliation(s)
- J P Kestner
- Department of Physics, University of Maryland Baltimore County, Baltimore, Maryland 21250, USA and Condensed Matter Theory Center, Department of Physics, University of Maryland, College Park, Maryland 20742, USA
| | - Xin Wang
- Condensed Matter Theory Center, Department of Physics, University of Maryland, College Park, Maryland 20742, USA
| | - Lev S Bishop
- Condensed Matter Theory Center, Department of Physics, University of Maryland, College Park, Maryland 20742, USA and Joint Quantum Institute, University of Maryland, College Park, Maryland 20742, USA
| | - Edwin Barnes
- Condensed Matter Theory Center, Department of Physics, University of Maryland, College Park, Maryland 20742, USA
| | - S Das Sarma
- Condensed Matter Theory Center, Department of Physics, University of Maryland, College Park, Maryland 20742, USA and Joint Quantum Institute, University of Maryland, College Park, Maryland 20742, USA
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