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High-Speed Neutron Imaging Using a Current-Biased Delay-Line Detector of Kinetic Inductance

Physical Review Applied 2018年第4期10卷 044044-044044页

作者： Hiroaki Shishido Yuya Miki Hiroyuki Yamaguchi Yuki Iizawa Vu The Dang Kenji M. Kojima Tomio Koyama Kenichi Oikawa Masahide Harada Shigeyuki Miyajima Mutsuo Hidaka Takayuki Oku Kazuhiko Soyama Soh Y. Suzuki Takekazu Ishida Department of Physics and Electronics Graduate School of Engineering Osaka Prefecture University Sakai Osaka 599-8531 Japan NanoSquare Research Institute Osaka Prefecture University Sakai Osaka 599-8531 Japan Muon Science Laboratory and Condensed Matter Research Center Institute of Materials Structure Science High Energy Accelerator Research Organization (KEK) Tsukuba Ibaraki 305-0801 Japan Department of Materials Structure Science The Graduate University for Advanced Studies Tsukuba Ibaraki 305-0801 Japan Division of Quantum and Radiation Engineering Osaka Prefecture University Sakai Osaka 599-8570 Japan Materials and Life Science Division J-PARC Center Japan Atomic Energy Agency Tokai Ibaraki 319-1195 Japan Advanced ICT Research Institute National Institute of Information and Communications Technology 588-2 Iwaoka Nishi-ku Kobe Hyogo 651-2492 Japan Advanced Industrial Science and Technology Tsukuba Ibaraki 305-8568 Japan Computing Research Center Applied Research Laboratory High Energy Accelerator Research Organization (KEK) Tsukuba Ibaraki 305-0801 Japan

We demonstrate the development of a high-speed neutron-imaging system via a solid-state superconducting detector. Our developed system, a current-biased kinetic-inductance detector (CBKID), operates in a delay-line mode to identify the position of a local hot spot in terms of four different arrival time stamps at the ends of the delay lines. Our detector comprises X and Y superconducting Nb meander lines, which are fed by a weak dc current, and a B10 conversion layer, which converts a neutron into two charged particles. The high-energy light ions (He4 or Li7) in the B10(n,α)7Li reaction are able to create two hot spots simultaneously in the X and Y meanders. A pair of electromagnetic-wave pulses are generated at the hot spot and signals of different polarities start propagating on each of the X and Y meanders toward the ends. The position of the original hot spot is determined by the difference in arrival time of the two pulses at the two ends. To measure the arrival times of the pulse signals, we developed a set of analog signal discriminators from the preset threshold levels using a time-to-digital converter (TDC), which is able to record the timing of the propagated pulses with 1-ns resolution over a time frame of 4.2 s. We successfully reconstructed the neutron image of a test pattern with a spatial resolution of 22 μm and a detection rate tolerance of a few 10 MHz/cm2.

关键词： Solid-state detectors Neutron imaging Neutron scattering Superconducting devices

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Information geometry approach to parameter estimation in hidden markov model

arXiv

引用

arXiv 2017年

作者： Hayashi, Masahito Shenzhen Institute for Quantum Science and Engineering Southern University of Science and Technology Shenzhen518055 China Guangdong Provincial Key Laboratory of Quantum Science and Engineering Southern University of Science and Technology Shenzhen518055 China Shenzhen Key Laboratory of Quantum Science and Engineering Southern University of Science and Technology Shenzhen518055 China Graduate School of Mathematics Nagoya University Nagoya464-8602 Japan Center for Advanced Intelligence Project RIKEN Tokyo103-0027 Japan Centre for Quantum Technologies National University of Singapore 117543 Singapore Center for Quantum Computing Peng Cheng Laboratory Shenzhen518066 China

We consider the estimation of the transition matrix of a hidden Markovian process by using information geometry with respect to transition matrices. In this paper, only the histogram of k-memory data is used for the estimation. To establish our method, we focus on a partial observation model with the Markovian process and we propose an efficient estimator whose asymptotic estimation error is given as the inverse of projective Fisher information of transition matrices. This estimator is applied to the estimation of the transition matrix of the hidden Markovian process. In this application, we carefully discuss the equivalence problem for hidden Markovian process on the tangent space. Copyright © 2017, The Authors. All rights reserved.

关键词： Inverse problems

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A Randomized Neural Network for Data Streams

A Randomized Neural Network for Data Streams

引用

International Joint Conference on Neural Networks

作者： Mahardhika Pratama Plamen P. Angelov Jie Lu Edwin Lughofer Manjeevan Seera C. P. Lim School of Engineering and Mathematical Sciences La Trobe University School of Computing and Communication Lancaster University Center for Quantum Computation and Intelligent Systems University of Technology Sydney Department of knowledge-based mathematical system Johannes Kepler University Faculty of Engineering Computing and Science Swinburne University of Technology (Sarawak Campus) Institute of Intelligent System Research and Innovation Deakin University

ISBN: (纸本)9781509061839

Randomized neural network (RNN) is a highly feasible solution in the era of big data because it offers a simple and fast working principle in processing dynamic and evolving data streams. This paper proposes a novel RNN, namely recurrent type-2 random vector functional link network (RT2McRVFLN), which provides a highly scalable solution for data streams in a strictly online and integrated framework. It is built upon the psychologically inspired concept of metacognitive learning, which covers three basic components of human learning: what-to-learn, how-to-learn, and when-to-learn. The what-to-learn selects important samples on the fly with the use of online active learning scenario, which renders our algorithm an online semi-supervised algorithm. The how-to-learn process combines an open structure of evolving concept and a randomized learning algorithm of random vector functional link network (RVFLN). The efficacy of the RT2McRVFLN has been numerically validated through two real-world case studies and comparisons with its counterparts, which arrive at a conclusive finding that our algorithm delivers a tradeoff between accuracy and simplicity.

关键词： Evolving Fuzzy Systems Fuzzy Neural Networks Type-2 Fuzzy Systems Sequential Learning

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Universal finestructure eraser for quantum dots

arXiv

引用

arXiv 2017年

作者： Fognini, A. Ahmadi, A. Daley, S.J. Reimer, M.E. Zwiller, V. Kavli Institute of Nanoscience Delft Delft University of Technology Delft2628 CJ Netherlands Institute for Quantum Computing and Department of Physics & Astronomy University of Waterloo WaterlooONN2L 3G1 Canada Institute for Quantum Computing Department of Electrical & Computer Engineering University of Waterloo WaterlooONN2L 3G1 Canada AlbaNova University Center StockholmSE - 106 91 Sweden

The measurable degree of entanglement from a quantum dot via the biexciton-exciton cascade depends crucially on the bright exciton fine-structure splitting and on the detection time resolution. Here, we propose an optical approach with fast rotating waveplates to erase this fine-structure splitting and therefore obtain a high degree of entanglement with near-unity efficiency. Our optical approach is possible with current technology and is also compatible with any quantum dot showing fine-structure splitting. Copyright © 2017, The Authors. All rights reserved.

关键词： Semiconductor quantum dots

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Experimental design for non-parametric correction of misspecified dynamical models

arXiv

引用

arXiv 2017年

作者： Shulkind, Gal Horesh, Lior Avron, Haim Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology CambridgeMA United States Quantum Computing IBM TJ Watson Research Center Yorktown HeightsNY United States Department of Applied Mathematics Tel Aviv University Israel

We consider a class of misspecified dynamical models where the governing term is only approximately known. Under the assumption that observations of the system’s evolution are accessible for various initial conditions, our goal is to infer a non-parametric correction to the misspecified driving term such as to faithfully represent the system dynamics and devise system evolution predictions for unobserved initial conditions. We model the unknown correction term as a Gaussian Process and analyze the problem of efficient experimental design to find an optimal correction term under constraints such as a limited experimental budget. We suggest a novel formulation for experimental design for this Gaussian Process and show that approximately optimal (up to a constant factor) designs may be efficiently derived by utilizing results from the literature on submodular optimization. Our numerical experiments exemplify the effectiveness of these techniques.62K05, 37M05, 62G08, 68T05 Copyright © 2017, The Authors. All rights reserved.

关键词： Dynamical systems

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Semi-data-driven network coarsening 25

Semi-data-driven network coarsening

引用

25th International Joint Conference on Artificial Intelligence, IJCAI 2016

作者： Gao, Li Wu, Jia Yang, Hong Qiao, Zhi Zhou, Chuan Hu, Yue Institute of Information Engineering Chinese Academy of Sciences Beijing China Quantum Computation and Intelligent Systems Centre University of Technology Sydney Australia MathWorks Beijing China Institute of Computing Technology Chinese Academy of Sciences Beijing China

Network coarsening refers to a new class of graph 'zoom-out' operations by grouping similar nodes and edges together so that a smaller equivalent representation of the graph can be obtained for big network analysis. Existing network coarsening methods consider that network structures are static and thus cannot handle dynamic networks. On the other hand, data-driven approaches can infer dynamic network structures by using network information spreading data. However, existing data-driven approaches neglect static network structures that are potentially useful for inferring big networks. In this paper, we present a new semi-data-driven network coarsening model to learn coarsened networks by embedding both static network structure data and dynamic network information spreading data. We prove that the learning model is convex and the Accelerated Proximal Gradient algorithm is adapted to achieve the global optima. Experiments on both synthetic and real-world data sets demonstrate the quality and effectiveness of the proposed method.

关键词： Coarsening

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Trion species-resolved quantum beats in MoSe2

arXiv

引用

arXiv 2017年

作者： Shepard, Gabriella D. Ardelean, Jenny V. Rhodes, Daniel A. Zhu, X.-Y. Hone, James C. Strauf, Stefan Department of Physics Stevens Institute of Technology HobokenNJ07030 United States Center for Distributed Quantum Computing Stevens Institute of Technology HobokenNJ07030 United States Department of Mechanical Engineering Columbia University New YorkNY10027 United States Department of Chemistry Columbia University New YorkNY10027 United States

Monolayer photonic materials offer a tremendous potential for on-chip optoelectronic devices. Their realization requires knowledge of optical coherence properties of excitons and trions that have so far been limited to nonlinear optical experiments carried out with strongly inhomogenously broadened material. Here we employ h-BN encapsulated and electrically gated MoSe2 to reveal coherence properties of trion-species directly in the linear optical response. Autocorrelation measurements reveal long dephasing times up to T2=1.16±0.05 ps for positively charged excitons. Gate dependent measurements provide evidence that the positively-charged trion forms via spatially localized hole states making this trion less prone to dephasing in the presence of elevated hole carrier concentrations. quantum beat signatures demonstrate coherent coupling between excitons and trions that have a dephasing time up to 0.6 ps, a two-fold increase over those in previous reports. A key merit of the prolonged exciton/trion coherences is that they were achieved in a linear optical experiment, and thus are directly relevant to applications in nanolasers, coherent control, and on-chip quantum information processing requiring long photon coherence. Copyright © 2017, The Authors. All rights reserved.

关键词： Excitons

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Secure Network Code for Adaptive and Active Attacks with No-Randomness in Intermediate Nodes

arXiv

引用

arXiv 2017年

作者： Cai, Ning Hayashi, Masahito The School of Information Science and Technology ShanghaiTech University China The Graduate School of Mathematics Nagoya University Furocho Chikusa-ku Nagoya464-8602 Japan Shenzhen Institute for Quantum Science and Engineering Southern University of Science and Technology No.1088 Xueyuan Avenue Nanshan District Shenzhen518055 China The Centre for Quantum Technologies National University of Singapore 3 Science Drive 2 117542 Singapore Center for Quantum Computing Peng Cheng Laboratory Shenzhen518000 China

In secure network coding, there is a possibility that the eavesdropper can improve her performance when she changes (contaminates) the information on the attacked edges (active attack) and chooses the attacked edges adaptively (adaptive attack). We analyze the security for network code over such types of attacks. We show that active and adaptive attacks cannot improve the performance of the eavesdropper when the code is linear. Further, we give a non-linear example, in which an adaptive attack improves the performance of the eavesdropper. We derive the capacity for the unicast case and the capacity region for the multicast case or the multiple multicast case in several examples of relay networks, beyond the minimum cut theorem, when no additional random number is allowed as scramble variables in the intermediate nodes. No prior study compared the difference of the capacity and the capacity region between the existence and the non-existence of randomness in the intermediate nodes under these network models even with non-adaptive and non-active attacks. Copyright © 2017, The Authors. All rights reserved.

关键词： Codes (symbols)

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Robust nano-fabrication of an integrated platform for spin control in a tunable microcavity

arXiv

引用

arXiv 2017年

作者： Bogdanović, Stefan Liddy, Madelaine S.Z. van Dam, Suzanne B. Coenen, Lisanne C. Fink, Thomas Lončar, Marko Hanson, Ronald QuTech Delft University of Technology PO Box 5046 Delft2600 GA Netherlands Institute for Quantum Computing Department of Electrical and Computer Engineering University of Waterloo WaterlooONN2L 3G1 Canada Institute of Quantum Electronics ETH Zürich ZürichCH-8093 Switzerland John A. Paulson School of Engineering and Applied Sciences Harvard University CambridgeMA02138 United States

Coupling nitrogen-vacancy centers in diamond to optical cavities is a promising way to enhance the efficiency of diamond based quantum networks. An essential aspect of the full toolbox required for the operation of these networks is the ability to achieve microwave control of the electron spin associated with this defect within the cavity framework. Here, we report on the fabrication of an integrated platform for microwave control of an NV center electron spin in an open, tunable Fabry-Pérot microcavity. A critical aspect of the measurements of the cavity’s finesse reveals that the presented fabrication process does not compromise its optical properties. We provide a method to incorporate a thin diamond slab into the cavity architecture and demonstrate control of the NV center spin. These results show the promise of this design for future cavity-enhanced NV center spin-photon entanglement experiments. Copyright © 2017, The Authors. All rights reserved.

关键词： Magnetic moments

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quantum key distribution with distinguishable decoy states

arXiv

引用

arXiv 2017年

作者： Huang, Anqi Sun, Shi-Hai Liu, Zhihong Makarov, Vadim Institute for Quantum Information State Key Laboratory of High Performance Computing College of Computer National University of Defense Technology Changsha410073 China Institute for Quantum Computing University of Waterloo WaterlooONN2L 3G1 Canada Department of Electrical and Computer Engineering University of Waterloo WaterlooONN2L 3G1 Canada College of Science National University of Defense Technology Changsha410073 China College of Mechatronic Engineering and Automation National University of Defense Technology Changsha410073 China Russian Quantum Center MISIS University Moscow Department of Physics and Astronomy University of Waterloo WaterlooONN2L 3G1 Canada

The decoy state protocol has been considered to be one of the most important methods to protect the security of quantum key distribution (QKD) with a weak coherent source. Here we test two experimental approaches to generating the decoy states with different intensities: modulation of the pump current of a semiconductor laser diode, and external modulation by an optical intensity modulator. The former approach shows a side-channel in the time domain that allows an attacker to distinguish s signal state from a decoy state, breaking a basic assumption in the protocol. We model a photon-number-splitting attack based on our experimental data, and show that it compromises the system's security. Then, based on the work of K. Tamaki et al. [New J. Phys. 18, 065008 (2016)], we obtain two analytical formulas to estimate the yield and error rate of single-photon pulses when the signal and decoy states are distinguishable. The distinguishability reduces the secure key rate below that of a perfect decoy-state protocol. To mitigate this reduction, we propose to calibrate the transmittance of the receiver (Bob's) unit. We apply our method to three QKD systems and estimate their secure key rates. Copyright © 2017, The Authors. All rights reserved.

关键词： Modulation

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