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Lee D, Lee S, Shon S. Qubit Adoption Method of a Quantum Computing-Based Metaheuristics Algorithm for Truss Structures Analysis. Biomimetics (Basel) 2023; 9:11. [PMID: 38248585 DOI: 10.3390/biomimetics9010011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 12/16/2023] [Accepted: 12/20/2023] [Indexed: 01/23/2024] Open
Abstract
Since the mention of the Fourth Industrial Revolution in 2016, quantum computers and quantum computing (QC) have emerged as key technologies. Many researchers are trying to realize quantum computers and quantum computing. In particular, most of the development and application of metaheuristics algorithms using quantum computing is focused on computer engineering fields. Cases in which the developed algorithm is applied to the optimal design of a building or the optimal design results presented by expanding the algorithm in various directions are very insufficient. Therefore, in this paper, we proposed four methods of adopting qubits to perform pitch adjusting in the optimization process of the QbHS (quantum-based harmony search) algorithm and applied it to TTO (truss topology optimization) using four methods to compare the results. The four methods of adopting qubits have the same or decreased number of qubits adopted as the number of iterations changes. As a result of applying TTO using four methods, convergence performance differed depending on the adoption method, and convergence performance was superior to conventional HS (harmony search) algorithms in all methods. The optimal design of structural engineering using such QC is expected to contribute to the revitalization of future technologies in the architectural field and the field of computer information systems.
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Affiliation(s)
- Donwoo Lee
- School of Industrial Design & Architectural Engineering, Korea University of Technology & Education, 1600 Chungjeol-ro, Byeongcheon-myeon, Cheonan 31253, Republic of Korea
| | - Seungjae Lee
- School of Industrial Design & Architectural Engineering, Korea University of Technology & Education, 1600 Chungjeol-ro, Byeongcheon-myeon, Cheonan 31253, Republic of Korea
| | - Sudeok Shon
- School of Industrial Design & Architectural Engineering, Korea University of Technology & Education, 1600 Chungjeol-ro, Byeongcheon-myeon, Cheonan 31253, Republic of Korea
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2
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Tanuma Y, Kladnik G, Schio L, van Midden Mavrič M, Anézo B, Zupanič E, Bavdek G, Canton-Vitoria R, Floreano L, Tagmatarchis N, Wegner HA, Morgante A, Ewels CP, Cvetko D, Arčon D. Noncontact Layer Stabilization of Azafullerene Radicals: Route toward High-Spin-Density Surfaces. ACS Nano 2023; 17:25301-25310. [PMID: 38085812 PMCID: PMC10753892 DOI: 10.1021/acsnano.3c08717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 12/04/2023] [Accepted: 12/07/2023] [Indexed: 12/27/2023]
Abstract
We deposit azafullerene C59N• radicals in a vacuum on the Au(111) surface for layer thicknesses between 0.35 and 2.1 monolayers (ML). The layers are characterized using X-ray photoemission (XPS) and X-ray absorption fine structure (NEXAFS) spectroscopy, low-temperature scanning tunneling microscopy (STM), and by density functional calculations (DFT). The singly unoccupied C59N orbital (SUMO) has been identified in the N 1s NEXAFS/XPS spectra of C59N layers as a spectroscopic fingerprint of the molecular radical state. At low molecular coverages (up to 1 ML), films of monomeric C59N are stabilized with the nonbonded carbon orbital neighboring the nitrogen oriented toward the Au substrate, whereas in-plane intermolecular coupling into diamagnetic (C59N)2 dimers takes over toward the completion of the second layer. By following the C59N• SUMO peak intensity with increasing molecular coverage, we identify an intermediate high-spin-density phase between 1 and 2 ML, where uncoupled C59N• monomers in the second layer with pronounced radical character are formed. We argue that the C59N• radical stabilization of this supramonolayer phase of monomers is achieved by suppressed coupling to the substrate. This results from molecular isolation on top of the passivating azafullerene contact layer, which can be explored for molecular radical state stabilization and positioning on solid substrates.
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Affiliation(s)
- Yuri Tanuma
- Jožef
Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia
- Center
for Advanced Research of Energy and Materials (CAREM), Hokkaido University, Kita 13, Nishi 8, Kitaku, Sapporo 060-8628, Japan
| | - Gregor Kladnik
- Faculty
of Mathematics and Physics, University of
Ljubljana, Jadranska 19, SI-1000 Ljubljana, Slovenia
- CNR-IOM, Istituto Officina dei Materiali, Basovizza Area Science Park, 34149 Trieste, Italy
| | - Luca Schio
- CNR-IOM, Istituto Officina dei Materiali, Basovizza Area Science Park, 34149 Trieste, Italy
| | | | - Bastien Anézo
- Institut
des Matériaux de Nantes Jean Rouxel (IMN), UMR 6502 CNRS, Nantes University, 44322 Nantes, France
| | - Erik Zupanič
- Jožef
Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia
| | - Gregor Bavdek
- CNR-IOM, Istituto Officina dei Materiali, Basovizza Area Science Park, 34149 Trieste, Italy
- Faculty
of
Education, University of Ljubljana, Kardeljeva ploščad
16, SI-1000 Ljubljana Slovenia
| | - Ruben Canton-Vitoria
- Theoretical
and Physical Chemistry Institute, National
Hellenic Research Foundation, 48 Vassileos Constantinou Avenue, Athens 11635, Greece
| | - Luca Floreano
- CNR-IOM, Istituto Officina dei Materiali, Basovizza Area Science Park, 34149 Trieste, Italy
| | - Nikos Tagmatarchis
- Theoretical
and Physical Chemistry Institute, National
Hellenic Research Foundation, 48 Vassileos Constantinou Avenue, Athens 11635, Greece
| | - Hermann A. Wegner
- Institute
of Organic Chemistry, Justus Liebig University
Giessen, Heinrich-Buff-Ring 17, 35392 Giessen, Germany
- Center
for Materials Research (ZfM/LaMa), Justus
Liebig University Giessen, Heinrich-Buff-Ring 16, 35392 Giessen, Germany
| | - Alberto Morgante
- CNR-IOM, Istituto Officina dei Materiali, Basovizza Area Science Park, 34149 Trieste, Italy
- Physics
Department, University of Trieste, Via Valerio 2, 34012 Trieste, Italy
| | - Christopher P. Ewels
- Institut
des Matériaux de Nantes Jean Rouxel (IMN), UMR 6502 CNRS, Nantes University, 44322 Nantes, France
| | - Dean Cvetko
- Jožef
Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia
- Faculty
of Mathematics and Physics, University of
Ljubljana, Jadranska 19, SI-1000 Ljubljana, Slovenia
- CNR-IOM, Istituto Officina dei Materiali, Basovizza Area Science Park, 34149 Trieste, Italy
| | - Denis Arčon
- Jožef
Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia
- Faculty
of Mathematics and Physics, University of
Ljubljana, Jadranska 19, SI-1000 Ljubljana, Slovenia
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3
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Lockyer SJ, Asthana D, Whitehead GFS, Vitorica‐Yrezabal IJ, Timco GA, McInnes EJL, Winpenny REP. Control and Transferability of Magnetic Interactions in Supramolecular Structures: Trimers of {Cr 7 Ni} Antiferromagnetic Rings. Chemistry 2023; 29:e202302360. [PMID: 37737455 PMCID: PMC10947047 DOI: 10.1002/chem.202302360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 09/13/2023] [Accepted: 09/22/2023] [Indexed: 09/23/2023]
Abstract
A synthetic strategy is demonstrated to prepare two distinct trimers of antiferromagnetically coupled {Cr7 Ni} rings, substantially varying the magnetic interactions between the spin centres. The interactions were studied using multi-frequency cw EPR: in a trimer linked via non-covalent H-bonding interactions no measurable interaction between rings was seen, while in a trimer linked via iso-nicotinate groups isotropic and anisotropic exchange interactions of +0.42 and -0.8 GHz, respectively, were observed. The latter are the same as those for a simpler hetero-dimer system, showing how the spin-spin interactions can be built in a predictable and modular manner in these systems.
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Affiliation(s)
- Selena J. Lockyer
- Department of ChemistryThe University of ManchesterOxford RoadManchesterM13 9PLUnited Kingdom
| | - Deepak Asthana
- Department of ChemistryThe University of ManchesterOxford RoadManchesterM13 9PLUnited Kingdom
| | - George F. S. Whitehead
- Department of ChemistryThe University of ManchesterOxford RoadManchesterM13 9PLUnited Kingdom
| | | | - Grigore. A. Timco
- Department of ChemistryThe University of ManchesterOxford RoadManchesterM13 9PLUnited Kingdom
| | - Eric J. L. McInnes
- Department of ChemistryThe University of ManchesterOxford RoadManchesterM13 9PLUnited Kingdom
| | - Richard E. P. Winpenny
- Department of ChemistryThe University of ManchesterOxford RoadManchesterM13 9PLUnited Kingdom
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Wang J, Jing Y, Cui MH, Lu YM, Ouyang Z, Shao C, Wang Z, Song Y. Spin Qubit in a 2D Gd III Na I -Based Oxamato Supramolecular Coordination Framework. Chemistry 2023; 29:e202301771. [PMID: 37665775 DOI: 10.1002/chem.202301771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 09/04/2023] [Accepted: 09/04/2023] [Indexed: 09/06/2023]
Abstract
Qubits are the basic unit of quantum information and computation. To realize quantum computing and information processing, the decoherence times of qubits must be long enough. Among the studies of molecule-based electron spin qubits, most of the work focused on the ions with the spin S=1/2, where only single-bit gates can be constructed. However, quantum operations require the qubits to interact with each other, so people gradually carry out relevant research in ions or systems with S>1/2 and multilevel states. In this work, a two-dimensional (2D) oxygen-coordinated GdIII NaI -based oxamato supramolecular coordination framework, Na[Gd(4-HOpa)4 (H2 O)] ⋅ 2H2 O (1, 4-HOpa=N-4-hydroxyphenyloxamate), was selected as a possible carrier of qubit. The field-induced slow magnetic relaxation shows this system has phonon bottleneck (PB) effect at low temperatures with a very weak magnetic anisotropy. The pulse electron paramagnetic resonance studies show the spin-lattice and spin-spin relaxation times are T1 =1.66 ms at 4 K and Tm =4.25 μs at 8 K for its diamagnetically diluted sample (1Gd0.12 %). It suggested that the relatively long decoherence time is mainly ascribed to its near isotropic and the PB effect from resonance phonon trapped for pure sample, while the dilution further improves its qubit performance.
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Affiliation(s)
- Jia Wang
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, 210023, Nanjing, P. R. China
| | - Yu Jing
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, 210023, Nanjing, P. R. China
| | - Ming-Hui Cui
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, 210023, Nanjing, P. R. China
| | - Yi-Ming Lu
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, 210023, Nanjing, P. R. China
| | - Zhongwen Ouyang
- Wuhan National High Magnetic Field Center & School of Physics, Huazhong University of Science and Technology, Gannan Normal University, 430074, Wuhan, P. R. China
| | - Chongyun Shao
- Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, 201800, Shanghai, P. R. China
| | - Zhenxing Wang
- Wuhan National High Magnetic Field Center & School of Physics, Huazhong University of Science and Technology, Gannan Normal University, 430074, Wuhan, P. R. China
| | - You Song
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, 210023, Nanjing, P. R. China
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Bahrami M, Vasilopoulos P. Transverse Magnetic Surface Plasmons in Graphene Nanoribbon Qubits: The Influence of a VO 2 Substrate. Nanomaterials (Basel) 2023; 13:718. [PMID: 36839087 PMCID: PMC9965028 DOI: 10.3390/nano13040718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 02/08/2023] [Accepted: 02/11/2023] [Indexed: 06/18/2023]
Abstract
We study the influence of the phase-change material VO2 on transverse magnetic (TM) surface plasmon (SP) modes in metallic arm-chair graphene nanoribbon (AGNR) qubits in the Lindhard approximation. We assess the effects of temperature as a dynamic knob for the transition from the insulating to the metallic phase on the TM SP modes in single-band (SB) and two-band (TB) transitions. We show that a VO2 substrate leads to TM SP modes in both SB and TB transitions. In addition, we observe that the SP modes have a lower frequency than those for a substrate of constant permittivity. In addition, we study the influence of the substrate-induced band gap Δ' on SP modes in TB transitions for the insulating and metallic phases of VO2.
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Affiliation(s)
- Mousa Bahrami
- Bita Quantum AI Inc., 2021 Av. Atwater, Montréal, QC H3H 2P2, Canada
| | - Panagiotis Vasilopoulos
- Department of Physics, Concordia University, 7141 Sherbrooke Ouest, Montréal, QC H4B 1R6, Canada
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6
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Nakazato H, Sergi A, Migliore A, Messina A. Invariant-Parameterized Exact Evolution Operator for SU(2) Systems with Time-Dependent Hamiltonian. Entropy (Basel) 2023; 25:e25010096. [PMID: 36673237 PMCID: PMC9857748 DOI: 10.3390/e25010096] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 12/28/2022] [Accepted: 12/29/2022] [Indexed: 06/01/2023]
Abstract
We report the step-by-step construction of the exact, closed and explicit expression for the evolution operator U(t) of a localized and isolated qubit in an arbitrary time-dependent field, which for concreteness we assume to be a magnetic field. Our approach is based on the existence of two independent dynamical invariants that enter the expression of SU(2) by means of two strictly related time-dependent, real or complex, parameters. The usefulness of our approach is demonstrated by exactly solving the quantum dynamics of a qubit subject to a controllable time-dependent field that can be realized in the laboratory. We further discuss possible applications to any SU(2) model, as well as the applicability of our method to realistic physical scenarios with different symmetry properties.
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Affiliation(s)
| | - Alessandro Sergi
- Dipartimento di Scienze Matematiche e Informatiche, Scienze Fisiche e Scienze della Terra, Università degli Studi di Messina, Viale F. Stagno d’Alcontres 31, 98166 Messina, Italy
- Institute of Systems Science, Durban University of Technology, P.O. Box 1334, Durban 4000, South Africa
| | - Agostino Migliore
- Department of Chemical Sciences, University di Padova, Via Francesco Marzolo, 1, 35131 Padova, Italy
| | - Antonino Messina
- Dipartimento di Matematica ed Informatica dell’Università di Palermo, Via Archirafi 34, 90123 Palermo, Italy
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7
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Schegolev AE, Klenov NV, Bogatskaya AV, Yusupov RD, Popov AM. A Pair of Coupled Waveguides as a Classical Analogue for a Solid-State Qubit. Sensors (Basel) 2022; 22:8286. [PMID: 36365983 PMCID: PMC9655956 DOI: 10.3390/s22218286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 10/25/2022] [Accepted: 10/27/2022] [Indexed: 06/16/2023]
Abstract
We have determined conditions when a pair of coupled waveguides, a common element for integrated room-temperature photonics, can act as a qubit based on a system with a double-well potential. Moreover, we have used slow-varying amplitude approximation (SVA) for the "classical" wave equation to study the propagation of electromagnetic beams in a couple of dielectric waveguides both analytically and numerically. As a part of an extension of the optical-mechanical analogy, we have considered examples of "quantum operations" on the electromagnetic wave state in a pair of waveguides. Furthermore, we have provided examples of "quantum-mechanical" calculations of nonlinear transfer functions for the implementation of the considered element in optical neural networks.
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Affiliation(s)
- Andrey E Schegolev
- D. V. Skobeltsyn Institute of Nuclear Physics, Moscow State University, 119991 Moscow, Russia
- Science and Research Department, Moscow Technical University of Communication and Informatics, 111024 Moscow, Russia
| | - Nikolay V Klenov
- Faculty of Physics, Moscow State University, 119991 Moscow, Russia
| | - Anna V Bogatskaya
- Faculty of Physics, Moscow State University, 119991 Moscow, Russia
- P. N. Lebedev Physical Institute, Russian Academy of Sciences, 119991 Moscow, Russia
| | - Rustam D Yusupov
- Science and Research Department, Moscow Technical University of Communication and Informatics, 111024 Moscow, Russia
- Faculty of Physics, Moscow State University, 119991 Moscow, Russia
| | - Alexander M Popov
- Faculty of Physics, Moscow State University, 119991 Moscow, Russia
- P. N. Lebedev Physical Institute, Russian Academy of Sciences, 119991 Moscow, Russia
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8
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Wang J, Guo G, Shan Z. SoK: Benchmarking the Performance of a Quantum Computer. Entropy (Basel) 2022; 24:1467. [PMID: 37420487 DOI: 10.3390/e24101467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 09/29/2022] [Accepted: 10/10/2022] [Indexed: 07/09/2023]
Abstract
The quantum computer has been claimed to show more quantum advantage than the classical computer in solving some specific problems. Many companies and research institutes try to develop quantum computers with different physical implementations. Currently, most people only focus on the number of qubits in a quantum computer and consider it as a standard to evaluate the performance of the quantum computer intuitively. However, it is quite misleading in most times, especially for investors or governments. This is because the quantum computer works in a quite different way than classical computers. Thus, quantum benchmarking is of great importance. Currently, many quantum benchmarks are proposed from different aspects. In this paper, we review the existing performance benchmarking protocols, models, and metrics. We classify the benchmarking techniques into three categories: physical benchmarking, aggregative benchmarking, and application-level benchmarking. We also discuss the future trend for quantum computer's benchmarking and propose setting up the QTOP100.
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Affiliation(s)
- Junchao Wang
- State Key Laboratory of Mathematical Engineering and Advanced Computing, Zhengzhou 450002, China
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China
| | - Guoping Guo
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China
| | - Zheng Shan
- State Key Laboratory of Mathematical Engineering and Advanced Computing, Zhengzhou 450002, China
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Brandenburger A, La Mura P, Zoble S. Rényi Entropy, Signed Probabilities, and the Qubit. Entropy (Basel) 2022; 24:1412. [PMCID: PMC9602278 DOI: 10.3390/e24101412] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Accepted: 09/30/2022] [Indexed: 06/16/2023]
Abstract
The states of the qubit, the basic unit of quantum information, are 2 × 2 positive semi-definite Hermitian matrices with trace 1. We contribute to the program to axiomatize quantum mechanics by characterizing these states in terms of an entropic uncertainty principle formulated on an eight-point phase space. We do this by employing Rényi entropy (a generalization of Shannon entropy) suitably defined for the signed phase-space probability distributions that arise in representing quantum states.
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Affiliation(s)
- Adam Brandenburger
- Stern School of Business, Tandon School of Engineering, NYU Shanghai, New York University, New York, NY 10012, USA
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10
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Surov IA. Quantum core affect. Color-emotion structure of semantic atom. Front Psychol 2022; 13:838029. [PMID: 36248471 PMCID: PMC9554469 DOI: 10.3389/fpsyg.2022.838029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 08/08/2022] [Indexed: 12/04/2022] Open
Abstract
Psychology suffers from the absence of mathematically-formalized primitives. As a result, conceptual and quantitative studies lack an ontological basis that would situate them in the company of natural sciences. The article addresses this problem by describing a minimal psychic structure, expressed in the algebra of quantum theory. The structure is demarcated into categories of emotion and color, renowned as elementary psychological phenomena. This is achieved by means of quantum-theoretic qubit state space, isomorphic to emotion and color experiences both in meaning and math. In particular, colors are mapped to the qubit states through geometric affinity between the HSL-RGB color solids and the Bloch sphere, widely used in physics. The resulting correspondence aligns with the recent model of subjective experience, producing a unified spherical map of emotions and colors. This structure is identified as a semantic atom of natural thinking-a unit of affectively-colored personal meaning, involved in elementary acts of a binary decision. The model contributes to finding a unified ontology of both inert and living Nature, bridging previously disconnected fields of research. In particular, it enables theory-based coordination of emotion, decision, and cybernetic sciences, needed to achieve new levels of practical impact.
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Pashin D, Bastrakova M, Satanin A, Klenov N. Bifurcation Oscillator as an Advanced Sensor for Quantum State Control. Sensors (Basel) 2022; 22:s22176580. [PMID: 36081037 PMCID: PMC9460148 DOI: 10.3390/s22176580] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 08/26/2022] [Accepted: 08/27/2022] [Indexed: 06/01/2023]
Abstract
We study bifurcation behavior of a high-quality (high-Q) Josephson oscillator coupled to a superconducting qubit. It is shown that the probability of capture into the state of dynamic equilibrium is sensitive to qubit states. On this basis we present a new measurement method for the superposition state of a qubit due to its influence on transition probabilities between oscillator levels located in the energy region near the classical separatrix. The quantum-mechanical behavior of a bifurcation oscillator is also studied, which makes it possible to understand the mechanism of "entanglement" of oscillator and qubit states during the measurement process. The optimal parameters of the driving current and the state of the oscillator are found for performing one-qubit gates with the required precision, when the influence on the qubit from measurement back-action is minimal. A measurement protocol for state populations of the qubit entangled with the oscillator is presented.
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Affiliation(s)
- Dmitrii Pashin
- Faculty of Physics, Lobachevsky State University of Nizhny Novgorod, 603950 Nizhny Novgorod, Russia
| | - Marina Bastrakova
- Faculty of Physics, Lobachevsky State University of Nizhny Novgorod, 603950 Nizhny Novgorod, Russia
- Russian Quantum Center, 143025 Moscow, Russia
| | - Arkady Satanin
- Higher School of Economics, Russia National Research University, 101000 Moscow, Russia
- Dukhov All-Russia Research Institute of Automatics, 101000 Moscow, Russia
| | - Nikolay Klenov
- Faculty of Physics, Lobachevsky State University of Nizhny Novgorod, 603950 Nizhny Novgorod, Russia
- Faculty of Physics, Lomonosov Moscow State University, 119991 Moscow, Russia
- Science and Research Department, Moscow Technical University of Communication and Informatics, 111024 Moscow, Russia
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12
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Singh R, Dutta M, Stroscio MA. Role of Confined Optical Phonons in Exciton Generation in Spherical Quantum Dot. Materials (Basel) 2022; 15:5545. [PMID: 36013681 PMCID: PMC9415422 DOI: 10.3390/ma15165545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 07/28/2022] [Accepted: 08/10/2022] [Indexed: 06/15/2023]
Abstract
Optical control of excitonic states in semiconducting quantum dots has enabled it to be deployed as a qubit for quantum information processing. For self-assembled quantum dots, these excitonic states couple with phonons in the barrier material, for which the previous studies have shown that such exciton-phonon coupling can also lead to the generation of exciton, paving the way for their deployment in qubit-state preparation. Previous studies on self-assembled quantum dots comprising polar materials have considered exciton-phonon coupling by treating phonon modes as bulk acoustic modes only, owing to nearly the same acoustic property of the dot and barrier material. However, the dimensional confinement leads to significant modification phonon modes, even though acoustic confinement is weak but optical confinement cannot be overlooked. In this paper, we investigate for the first time the exciton-optical phonon coupling using dielectric continuum model duly accounting for the dimensional confinement leading to exciton generation. We report that at low temperatures (below 10 K), the exciton creation rate attributed to confined optical phonon is approximately 5.7 times (~6) slower than bulk acoustic phonons, which cannot be ignored, and it should be accounted for in determining the effective phonon assisted exciton creation rate.
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Affiliation(s)
- Ramji Singh
- Department of Electrical and Computer Engineering, University of Illinois at Chicago, 851 S Morgan Street, Chicago, IL 60607, USA
| | - Mitra Dutta
- Department of Electrical and Computer Engineering, University of Illinois at Chicago, 851 S Morgan Street, Chicago, IL 60607, USA
- Department of Physics, University of Illinois at Chicago, 845 W Taylor Street, Chicago, IL 60607, USA
| | - Michael A. Stroscio
- Department of Electrical and Computer Engineering, University of Illinois at Chicago, 851 S Morgan Street, Chicago, IL 60607, USA
- Department of Physics, University of Illinois at Chicago, 845 W Taylor Street, Chicago, IL 60607, USA
- Department of Bioengineering, University of Illinois at Chicago, 851 S Morgan Street, Chicago, IL 60607, USA
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Jones L, Sadhukhan T, Schatz GC. Localized π Surface States on 2D Molybdenum Disulfide from Carbene-Functionalization as a Qubit Design Strategy. ACS Phys Chem Au 2022; 2:277-281. [PMID: 36855415 PMCID: PMC9955177 DOI: 10.1021/acsphyschemau.1c00055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Surface chemistry is increasingly important for a number of applications, from catalysis to molecular qubits. For the qubit application, it is imperative that the energy levels of surface species involved in the process of interest are energetically distinct-that is addressable and not buried below or coincident with the substrate energy levels. One way to afford this is through chemical functionalization with derivatives that impart the property of choice to the interface. In this Letter, we report on the nature of the bond between a carbene moiety and an MoS2 surface. With density functional theory (DFT) and spin-polarized calculations, we first observe states in the band structure that pertain to the carbene group and then prove their origin. Importantly, we find localized π-states in the band gap that are due to π-electrons that are part of a diene attached to the carbene carbon and are not available in bonding configurations without the π conjugation. These lead to open-shell monocationic structures involving midgap HOMOs with densities on the carbene moiety. Both neutral and cationic forms of the carbenes are energetically separate from the MoS2 substrate, thus useful for optical manipulation. We explore several different choices of the carbene moieties, and show that those based on fused thiophene and bithiophene structures are the most favorable for localization, while purely carbon-based aromatic structures lead to states that are delocalized onto the MoS2 and thus less useful. These findings are potentially of interest to the design and synthesis of future molecular qubit candidates for device fabrication.
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14
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Viitaniemi MLK, Zimmermann C, Niaouris V, D'Ambrosia SH, Wang X, Kumar ES, Mohammadbeigi F, Watkins SP, Fu KMC. Coherent Spin Preparation of Indium Donor Qubits in Single ZnO Nanowires. Nano Lett 2022; 22:2134-2139. [PMID: 35108020 DOI: 10.1021/acs.nanolett.1c04156] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Shallow donors in ZnO are promising candidates for photon-mediated quantum technologies. Utilizing the indium donor, we show that favorable donor-bound exciton optical and electron spin properties are retained in isolated ZnO nanowires. The inhomogeneous optical line width of single nanowires (60 GHz) is within a factor of 2 of bulk single-crystalline ZnO. Spin initialization via optical pumping is demonstrated and coherent population trapping is observed. The two-photon absorption width approaches the theoretical limit expected due to the hyperfine interaction between the indium nuclear spin and the donor-bound electron.
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Affiliation(s)
- Maria L K Viitaniemi
- Department of Physics, University of Washington, Seattle, Washington 98195, United States
| | - Christian Zimmermann
- Department of Physics, University of Washington, Seattle, Washington 98195, United States
| | - Vasileios Niaouris
- Department of Physics, University of Washington, Seattle, Washington 98195, United States
| | - Samuel H D'Ambrosia
- Department of Physics, University of Washington, Seattle, Washington 98195, United States
| | - Xingyi Wang
- Department of Electrical Engineering, University of Washington, Seattle, Washington 98195, United States
| | - E Senthil Kumar
- Department of Physics, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Faezeh Mohammadbeigi
- Department of Physics, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Simon P Watkins
- Department of Physics, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Kai-Mei C Fu
- Department of Physics, University of Washington, Seattle, Washington 98195, United States
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15
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'Giron' Koetsier PA, Cantor EJ. A simple approach for effective shearing and reliable concentration measurement of ultra-high-molecular-weight DNA. Biotechniques 2021; 71:439-44. [PMID: 34232102 DOI: 10.2144/btn-2021-0051] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Pipetting and concentration measurement of viscous ultra-high-molecular-weight (UHMW) DNA samples is challenging and often highly imprecise. Effective guidelines for handling UHMW samples are missing in the field. Herein, a simple and low-cost workflow is presented that enables accurate pipetting and reliable concentration measurement. Central to the workflow is the shearing of representative small aliquots of UHMW DNA samples to a fragment size <150 kb by vortexing them for 1 min with a glass bead in a round-bottomed 2-ml tube. Additionally, a solution is provided for accurate quantitation of high-molecular-weight DNA with fluorometric (Qubit [Thermo Fisher Scientific, MA, USA]) methods by using an appropriate genomic DNA standard, resulting in values that match spectrophotometric (Nanodrop [Thermo Fisher Scientific]) optical density readings.
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16
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Mirzoyan R, Kazmierczak NP, Hadt RG. Deconvolving Contributions to Decoherence in Molecular Electron Spin Qubits: A Dynamic Ligand Field Approach. Chemistry 2021; 27:9482-9494. [PMID: 33855760 DOI: 10.1002/chem.202100845] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Indexed: 12/16/2022]
Abstract
In the past decade, transition metal complexes have gained momentum as electron spin-based quantum bit (qubit) candidates due to their synthetic tunability and long achievable coherence times. The decoherence of magnetic quantum states imposes a limit on the use of these qubits for quantum information technologies, such as quantum computing, sensing, and communication. With rapid recent development in the field of molecular quantum information science, a variety of chemical design principles for prolonging coherence in molecular transition metal qubits have been proposed. Here the spin-spin, motional, and spin-phonon regimes of decoherence are delineated, outlining design principles for each. It is shown how dynamic ligand field models can provide insights into the intramolecular vibrational contributions in the spin-phonon decoherence regime. This minireview aims to inform the development of molecular quantum technologies tailored for different environments and conditions.
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Affiliation(s)
- Ruben Mirzoyan
- Division of Chemistry and Chemical Engineering, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, CA 91125, USA
| | - Nathanael P Kazmierczak
- Division of Chemistry and Chemical Engineering, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, CA 91125, USA
| | - Ryan G Hadt
- Division of Chemistry and Chemical Engineering, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, CA 91125, USA
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17
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Man'ko OV, Man'ko VI. Probability Representation of Quantum States. Entropy (Basel) 2021; 23:549. [PMID: 33946800 DOI: 10.3390/e23050549] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 04/25/2021] [Accepted: 04/27/2021] [Indexed: 11/17/2022]
Abstract
The review of new formulation of conventional quantum mechanics where the quantum states are identified with probability distributions is presented. The invertible map of density operators and wave functions onto the probability distributions describing the quantum states in quantum mechanics is constructed both for systems with continuous variables and systems with discrete variables by using the Born's rule and recently suggested method of dequantizer-quantizer operators. Examples of discussed probability representations of qubits (spin-1/2, two-level atoms), harmonic oscillator and free particle are studied in detail. Schrödinger and von Neumann equations, as well as equations for the evolution of open systems, are written in the form of linear classical-like equations for the probability distributions determining the quantum system states. Relations to phase-space representation of quantum states (Wigner functions) with quantum tomography and classical mechanics are elucidated.
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18
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Chan KW, Sahasrabudhe H, Huang W, Wang Y, Yang HC, Veldhorst M, Hwang JCC, Mohiyaddin FA, Hudson FE, Itoh KM, Saraiva A, Morello A, Laucht A, Rahman R, Dzurak AS. Exchange Coupling in a Linear Chain of Three Quantum-Dot Spin Qubits in Silicon. Nano Lett 2021; 21:1517-1522. [PMID: 33481612 DOI: 10.1021/acs.nanolett.0c04771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Quantum gates between spin qubits can be implemented leveraging the natural Heisenberg exchange interaction between two electrons in contact with each other. This interaction is controllable by electrically tailoring the overlap between electronic wave functions in quantum dot systems, as long as they occupy neighboring dots. An alternative route is the exploration of superexchange-the coupling between remote spins mediated by a third idle electron that bridges the distance between quantum dots. We experimentally demonstrate direct exchange coupling and provide evidence for second neighbor mediated superexchange in a linear array of three single-electron spin qubits in silicon, inferred from the electron spin resonance frequency spectra. We confirm theoretically, through atomistic modeling, that the device geometry only allows for sizable direct exchange coupling for neighboring dots, while next-nearest neighbor coupling cannot stem from the vanishingly small tail of the electronic wave function of the remote dots, and is only possible if mediated.
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Affiliation(s)
- Kok Wai Chan
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Harshad Sahasrabudhe
- Department of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47907, United States
| | - Wister Huang
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Yu Wang
- Department of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47907, United States
| | - Henry C Yang
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Menno Veldhorst
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Jason C C Hwang
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Fahd A Mohiyaddin
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Fay E Hudson
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Kohei M Itoh
- School of Fundamental Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522, Japan
| | - Andre Saraiva
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Andrea Morello
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Arne Laucht
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Rajib Rahman
- Department of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47907, United States
- School of Physics, The University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Andrew S Dzurak
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales 2052, Australia
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19
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López-Saldívar JA, Castaños O, Man’ko MA, Man’ko VI. A New Mechanism of Open System Evolution and Its Entropy Using Unitary Transformations in Noncomposite Qudit Systems. Entropy (Basel) 2019; 21:e21080736. [PMID: 33267450 PMCID: PMC7515265 DOI: 10.3390/e21080736] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 06/26/2019] [Accepted: 07/24/2019] [Indexed: 11/16/2022]
Abstract
The evolution of an open system is usually associated with the interaction of the system with an environment. A new method to study the open-type system evolution of a qubit (two-level atom) state is established. This evolution is determined by a unitary transformation applied to the qutrit (three-level atom) state, which defines the qubit subsystems. This procedure can be used to obtain different qubit quantum channels employing unitary transformations into the qutrit system. In particular, we study the phase damping and spontaneous-emission quantum channels. In addition, we mention a proposal for quasiunitary transforms of qubits, in view of the unitary transform of the total qutrit system. The experimental realization is also addressed. The probability representation of the evolution and its information-entropic characteristics are considered.
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Affiliation(s)
- Julio A. López-Saldívar
- Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Apdo. Postal 70-543, Ciudad de México 04510, Mexico
- Moscow Institute of Physics and Technology, State University, Institutskii Per. 9, Dolgoprudnyi, Moscow 141700, Russia
- Correspondence:
| | - Octavio Castaños
- Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Apdo. Postal 70-543, Ciudad de México 04510, Mexico
| | | | - Vladimir I. Man’ko
- Moscow Institute of Physics and Technology, State University, Institutskii Per. 9, Dolgoprudnyi, Moscow 141700, Russia
- Lebedev Physical Institute, Leninskii Prospect 53, Moscow 119991, Russia
- Department of Physics, Tomsk State University, Lenin Avenue 36, Tomsk 634050, Russia
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20
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Abstract
Semiconductors, a significant type of material in the information era, are becoming more and more powerful in the field of quantum information. In recent decades, semiconductor quantum computation was investigated thoroughly across the world and developed with a dramatically fast speed. The research varied from initialization, control and readout of qubits, to the architecture of fault-tolerant quantum computing. Here, we first introduce the basic ideas for quantum computing, and then discuss the developments of single- and two-qubit gate control in semiconductors. Up to now, the qubit initialization, control and readout can be realized with relatively high fidelity and a programmable two-qubit quantum processor has even been demonstrated. However, to further improve the qubit quality and scale it up, there are still some challenges to resolve such as the improvement of the readout method, material development and scalable designs. We discuss these issues and introduce the forefronts of progress. Finally, considering the positive trend of the research on semiconductor quantum devices and recent theoretical work on the applications of quantum computation, we anticipate that semiconductor quantum computation may develop fast and will have a huge impact on our lives in the near future.
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Affiliation(s)
- Xin Zhang
- Key Laboratory of Quantum Information, CAS, University of Science and Technology of China, Hefei 230026, China
- Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei 230026, China
| | - Hai-Ou Li
- Key Laboratory of Quantum Information, CAS, University of Science and Technology of China, Hefei 230026, China
- Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei 230026, China
| | - Gang Cao
- Key Laboratory of Quantum Information, CAS, University of Science and Technology of China, Hefei 230026, China
- Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei 230026, China
| | - Ming Xiao
- Key Laboratory of Quantum Information, CAS, University of Science and Technology of China, Hefei 230026, China
- Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei 230026, China
| | - Guang-Can Guo
- Key Laboratory of Quantum Information, CAS, University of Science and Technology of China, Hefei 230026, China
- Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei 230026, China
| | - Guo-Ping Guo
- Key Laboratory of Quantum Information, CAS, University of Science and Technology of China, Hefei 230026, China
- Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei 230026, China
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21
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Edwards PR, O'Donnell KP, Singh AK, Cameron D, Lorenz K, Yamaga M, Leach JH, Kappers MJ, Boćkowski M. Hysteretic Photochromic Switching (HPS) in Doubly Doped GaN(Mg):Eu-A Summary of Recent Results. Materials (Basel) 2018; 11:E1800. [PMID: 30248983 DOI: 10.3390/ma11101800] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 08/13/2018] [Accepted: 09/19/2018] [Indexed: 12/03/2022]
Abstract
Europium is the most-studied and least-well-understood rare earth ion (REI) dopant in GaN. While attempting to increase the efficiency of red GaN light-emitting diodes (LEDs) by implanting Eu+ into p-type GaN templates, the Strathclyde University group, in collaboration with IST Lisbon and Unipress Warsaw, discovered hysteretic photochromic switching (HPS) in the photoluminescence spectrum of doubly doped GaN(Mg):Eu. Our recent work, summarised in this contribution, has used time-, temperature- and light-induced changes in the Eu intra-4f shell emission spectrum to deduce the microscopic nature of the Mg-Eu defects that form in this material. As well as shedding light on the Mg acceptor in GaN, we propose a possible role for these emission centres in quantum information and computing.
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22
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Abstract
Scientists want to comprehend and control complex systems. Their success depends on the ability to face also the challenges of the corresponding computational complexity. A promising research line is artificial intelligence (AI). In AI, fuzzy logic plays a significant role because it is a suitable model of the human capability to compute with words, which is relevant when we make decisions in complex situations. The concept of fuzzy set pervades the natural information systems (NISs), such as living cells, the immune and the nervous systems. This paper describes the fuzziness of the NISs, in particular of the human nervous system. Moreover, it traces three pathways to process fuzzy logic by molecules and their assemblies. The fuzziness of the molecular world is useful for the development of the chemical artificial intelligence (CAI). CAI will help to face the challenges that regard both the natural and the computational complexity.
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Affiliation(s)
- Pier Luigi Gentili
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Via Elce di sotto 8, 06123 Perugia, Italy.
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23
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Abstract
Ions trapped in a quadrupole Paul trap have been considered one of the strong physical candidates to implement quantum information processing. This is due to their long coherence time and their capability to manipulate and detect individual quantum bits (qubits). In more recent years, microfabricated surface ion traps have received more attention for large-scale integrated qubit platforms. This paper presents a microfabrication methodology for ion traps using micro-electro-mechanical system (MEMS) technology, including the fabrication method for a 14 µm-thick dielectric layer and metal overhang structures atop the dielectric layer. In addition, an experimental procedure for trapping ytterbium (Yb) ions of isotope 174 (174Yb+) using 369.5 nm, 399 nm, and 935 nm diode lasers is described. These methodologies and procedures involve many scientific and engineering disciplines, and this paper first presents the detailed experimental procedures. The methods discussed in this paper can easily be extended to the trapping of Yb ions of isotope 171 (171Yb+) and to the manipulation of qubits.
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Affiliation(s)
- Seokjun Hong
- ISRC/ASRI, Department of Electrical and Computer Engineering, Seoul National University
| | - Minjae Lee
- ISRC/ASRI, Department of Electrical and Computer Engineering, Seoul National University
| | | | - Dong-Il Dan Cho
- ISRC/ASRI, Department of Electrical and Computer Engineering, Seoul National University
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24
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Kawakami E, Jullien T, Scarlino P, Ward DR, Savage DE, Lagally MG, Dobrovitski VV, Friesen M, Coppersmith SN, Eriksson MA, Vandersypen LMK. Gate fidelity and coherence of an electron spin in an Si/SiGe quantum dot with micromagnet. Proc Natl Acad Sci U S A 2016; 113:11738-11743. [PMID: 27698123 PMCID: PMC5081655 DOI: 10.1073/pnas.1603251113] [Citation(s) in RCA: 105] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The gate fidelity and the coherence time of a quantum bit (qubit) are important benchmarks for quantum computation. We construct a qubit using a single electron spin in an Si/SiGe quantum dot and control it electrically via an artificial spin-orbit field from a micromagnet. We measure an average single-qubit gate fidelity of ∼99% using randomized benchmarking, which is consistent with dephasing from the slowly evolving nuclear spins in the substrate. The coherence time measured using dynamical decoupling extends up to ∼400 μs for 128 decoupling pulses, with no sign of saturation. We find evidence that the coherence time is limited by noise in the 10-kHz to 1-MHz range, possibly because charge noise affects the spin via the micromagnet gradient. This work shows that an electron spin in an Si/SiGe quantum dot is a good candidate for quantum information processing as well as for a quantum memory, even without isotopic purification.
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Affiliation(s)
- Erika Kawakami
- QuTech, 2628 CJ Delft, The Netherlands; Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ Delft, The Netherlands
| | - Thibaut Jullien
- QuTech, 2628 CJ Delft, The Netherlands; Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ Delft, The Netherlands
| | - Pasquale Scarlino
- QuTech, 2628 CJ Delft, The Netherlands; Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ Delft, The Netherlands
| | | | | | | | | | - Mark Friesen
- University of Wisconsin-Madison, Madison, WI 53706
| | | | | | - Lieven M K Vandersypen
- QuTech, 2628 CJ Delft, The Netherlands; Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ Delft, The Netherlands; Components Research, Intel Corporation, Hillsboro, OR 97124
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25
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Srinivasan V, Manne AK, Patnaik SG, Ramamurthy SS. Cellphone Monitoring of Multi- Qubit Emission Enhancements from Pd-Carbon Plasmonic Nanocavities in Tunable Coupling Regimes with Attomolar Sensitivity. ACS Appl Mater Interfaces 2016; 8:23281-8. [PMID: 27529116 DOI: 10.1021/acsami.6b07445] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We demonstrate for the first time the tuning of qubit emission based on cavity engineering on plasmonic silver thin films. This tunable transition from weak to strong coupling regime in plasmon-coupled fluorescence platform was achieved with the use of palladium nanocomposites. In addition to our recently established correlation between Purcell factor and surface plasmon-coupled emission enhancements, we now show that the qubit-cavity environment experiences the Purcell effect, Casimir force, internal fano resonance, and Rabi splitting. Finite-difference time-domain simulations and time correlated single photon counting studies helped probe the molecular structure of the radiating dipole, rhodamine-6G, in palladium-based nanocavities. The sensitivity of the qubit-cavity mode helped attain a DNA detection limit of 1 aM (attomolar) and multianalyte sensing at picomolar concentration with the use of a smartphone camera and CIE color space. We believe that this low-cost technology will lay the groundwork for mobile phone-based next-gen plasmonic sensing devices.
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Affiliation(s)
- Venkatesh Srinivasan
- Plasmonics Laboratory, Department of Chemistry, Sri Sathya Sai Institute of Higher Learning , Prasanthi Nilayam, Puttaparthi, Anantapur, Andhra Pradesh, India 515134
| | - Anupam Kumar Manne
- Plasmonics Laboratory, Department of Chemistry, Sri Sathya Sai Institute of Higher Learning , Prasanthi Nilayam, Puttaparthi, Anantapur, Andhra Pradesh, India 515134
| | - Sai Gourang Patnaik
- Plasmonics Laboratory, Department of Chemistry, Sri Sathya Sai Institute of Higher Learning , Prasanthi Nilayam, Puttaparthi, Anantapur, Andhra Pradesh, India 515134
| | - Sai Sathish Ramamurthy
- Plasmonics Laboratory, Department of Chemistry, Sri Sathya Sai Institute of Higher Learning , Prasanthi Nilayam, Puttaparthi, Anantapur, Andhra Pradesh, India 515134
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26
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Takeda K, Kamioka J, Otsuka T, Yoneda J, Nakajima T, Delbecq MR, Amaha S, Allison G, Kodera T, Oda S, Tarucha S. A fault-tolerant addressable spin qubit in a natural silicon quantum dot. Sci Adv 2016; 2:e1600694. [PMID: 27536725 PMCID: PMC4982751 DOI: 10.1126/sciadv.1600694] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 07/12/2016] [Indexed: 05/18/2023]
Abstract
Fault-tolerant quantum computing requires high-fidelity qubits. This has been achieved in various solid-state systems, including isotopically purified silicon, but is yet to be accomplished in industry-standard natural (unpurified) silicon, mainly as a result of the dephasing caused by residual nuclear spins. This high fidelity can be achieved by speeding up the qubit operation and/or prolonging the dephasing time, that is, increasing the Rabi oscillation quality factor Q (the Rabi oscillation decay time divided by the π rotation time). In isotopically purified silicon quantum dots, only the second approach has been used, leaving the qubit operation slow. We apply the first approach to demonstrate an addressable fault-tolerant qubit using a natural silicon double quantum dot with a micromagnet that is optimally designed for fast spin control. This optimized design allows access to Rabi frequencies up to 35 MHz, which is two orders of magnitude greater than that achieved in previous studies. We find the optimum Q = 140 in such high-frequency range at a Rabi frequency of 10 MHz. This leads to a qubit fidelity of 99.6% measured via randomized benchmarking, which is the highest reported for natural silicon qubits and comparable to that obtained in isotopically purified silicon quantum dot-based qubits. This result can inspire contributions to quantum computing from industrial communities.
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Affiliation(s)
- Kenta Takeda
- RIKEN, Center for Emergent Matter Science, Wako-shi, Saitama 351-0198, Japan
- Corresponding author.
| | - Jun Kamioka
- Department of Physical Electronics and Quantum Nanoelectronics Research Center, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo 152-8552, Japan
| | - Tomohiro Otsuka
- RIKEN, Center for Emergent Matter Science, Wako-shi, Saitama 351-0198, Japan
| | - Jun Yoneda
- RIKEN, Center for Emergent Matter Science, Wako-shi, Saitama 351-0198, Japan
| | - Takashi Nakajima
- RIKEN, Center for Emergent Matter Science, Wako-shi, Saitama 351-0198, Japan
| | - Matthieu R. Delbecq
- RIKEN, Center for Emergent Matter Science, Wako-shi, Saitama 351-0198, Japan
| | - Shinichi Amaha
- RIKEN, Center for Emergent Matter Science, Wako-shi, Saitama 351-0198, Japan
| | - Giles Allison
- RIKEN, Center for Emergent Matter Science, Wako-shi, Saitama 351-0198, Japan
| | - Tetsuo Kodera
- Department of Physical Electronics and Quantum Nanoelectronics Research Center, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo 152-8552, Japan
| | - Shunri Oda
- Department of Physical Electronics and Quantum Nanoelectronics Research Center, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo 152-8552, Japan
| | - Seigo Tarucha
- RIKEN, Center for Emergent Matter Science, Wako-shi, Saitama 351-0198, Japan
- Department of Applied Physics, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
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27
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Tsai JS. Toward a superconducting quantum computer. Harnessing macroscopic quantum coherence. Proc Jpn Acad Ser B Phys Biol Sci 2010; 86:275-292. [PMID: 20431256 PMCID: PMC3417795 DOI: 10.2183/pjab.86.275] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/16/2009] [Accepted: 02/09/2010] [Indexed: 05/29/2023]
Abstract
Intensive research on the construction of superconducting quantum computers has produced numerous important achievements. The quantum bit (qubit), based on the Josephson junction, is at the heart of this research. This macroscopic system has the ability to control quantum coherence. This article reviews the current state of quantum computing as well as its history, and discusses its future. Although progress has been rapid, the field remains beset with unsolved issues, and there are still many new research opportunities open to physicists and engineers.
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Affiliation(s)
- Jaw-Shen Tsai
- Nano Electronics Research Laboratories, NEC and Advanced Science Institute, RIKEN, 34 Miyukigaoka, Ibaraki, Japan.
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