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Influence of structural defects on charge density waves in 1T-TaS_(2)

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Nano Research 2023年第8期16卷 11528-11539页

作者： Iaroslav Lutsyk Karol Szalowski Pawel Krukowski Pawel Dabrowski Maciej Rogala Witold Kozlowski Maxime Le Ster Michal Piskorski Dorota A.Kowalczyk Wojciech Rys Rafal Dunal Aleksandra Nadolska Klaudia Toczek Przemyslaw Przybysz Ewa Lacinska Johannes Binder Andrzej Wysmolek Natalia Olszowska Jacek J.Kolodziej Martin Gmitra Takuma Hattori Yuji Kuwahara Guang Bian Tai-Chang Chiang Pawel J.Kowalczyk Faculty of Physics and Applied Informatics University of LodzPomorska 149/15390-236 LodzPoland Faculty of Physics University of WarsawPasteura 502-093 WarsawPoland Faculty of Physics Astronomyand Applied Computer ScienceJagiellonian UniversityLojasiewicza 1130-348 KrakowPoland National Synchrotron Radiation Centre SOLARIS Jagiellonian UniversityCzerwone Maki 9830-392 KrakówPoland Institute of Physics Faculty of SciencePavol JozefŠafárik University in KošicePark Angelinum 904001 KošiceSlovakia Institute of Experimental Physics Slovak Academy of SciencesWatsonova 4704001 KošiceSlovakia Department of Precision Engineering Graduate School of EngineeringOsaka University2-1 Yamada-okaSuita 565-0871Japan Department of Physics and Astronomy University of MissouriColumbiaMissouri 65211USA Department of Physics and Frederick Seitz Materials Research Laboratory University of Illinois at Urbana-ChampaignUrbanaIllinois 61801-3080USA

The influence of intrinsic defects of 1T-TaS_(2)on charge density waves(CDWs)is studied using scanning tunneling microscopy and spectroscopy(STM,STS),angle-resolved photoelectron spectroscopy(ARPES),and density functional theory(DFT).We identify several types of structural defects and find that most have a local character limited to a single CDW site,with a single exception which effectively behaves as a dopant,leading to band-bending and affecting multiple neighboring *** only one type of defect can be observed by STM topographic imaging,all defects are easily resolved in STS *** results indicate modulation of the Mott band gap commensurate with the CDW and breaking of the three-fold symmetry of electronic *** calculations(with included Coulomb interactions)are used to investigate the electronic structure,focusing on both sulfur vacancy and oxygen-sulfur *** sulfur vacancy system,characterized with a metallic behavior,is identified as the origin of one of the experimentally observed ***,the effect of oxidation of 1T-TaS_(2)depends on the substitution site,leading to the heterogeneity of electronic properties.

关键词： structural charge sulfur

Path Planning of Mobile Robot Based on Dynamic Chaotic Ant Colony Optimization Algorithm

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Path Planning of Mobile Robot Based on Dynamic Chaotic Ant C...

International Conference on Information, Communication and Networks (ICICN)

作者： Xiaoting Li Tingpei Huang Haihua Chen Yucheng Zhang Luo Xu Yingying Liu College of Oceanography and Space Informatics China University of Petroleum Qingdao China College of Computer Science and Technology China University of Petroleum Qingdao China Chinese Academy of Sciences Institute of Computing Technology Beijing China Engineering Laboratory of Intelligent Agricultural Machinery Equipment Chinese Academy of Sciences Beijing China

ISBN: (纸本)9781665490832

In this paper, a Dynamic Chaotic Ant Colony Optimization (DCACO) algorithm is proposed to solve the problems of traditional Ant Colony Optimization (ACO) algorithm in mobile robot path planning, such as long time consuming, slow convergence speed and easy to fall into local optimum. In DCACO, cosine annealing strategy is used to improve the expectation heuristic factor to balance the global search ability and convergence speed of the algorithm. In addition, this paper proposes a dynamic chaotic ant colony system, whose core is that improved logistic chaotic operator disturbs pheromone update in the early stage of iteration to avoid falling into local optimization, and is eliminated in the later stage to ensure the convergence speed. The experimental results show that this algorithm is effective and superior in path searching performance and convergence speed compared with the existing state-of-the-art algorithms.

关键词： Ant colony optimization Annealing Chaotic communication Heuristic algorithms Simulated annealing Path planning Mobile robots

An Optimizing Method for Performance and ResourceUtilization in Quantum Machine Learning Circuits

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Research Square

Research Square 2022年

作者： Salehi, Tahereh Zomorodi, Mariam Plawiak, Pawel Abbaszade, Mina Salari, Vahid Department of Computer Engineering Ferdowsi University of Mashhad Mashhad Iran Department of Computer Science Faculty of Computer Science and Telecommunications Cracow University of Technology Krakow Poland Theoretical and Applied Informatics Polish Academy of Sciences Gliwice Poland Department of Physics Isfahan University of Technology Isfahan84156-83111 Iran Bilbao Spain Department of Physics and Astronomy Howard University WashingtonDC20059 United States

Quantum computing is a new and advanced topic that refers to calculations based on the principles of quantum mechanics. It makes certain kinds of problems be solved easier compared to classical computers. This advantage of quantum computing can be used to implement many existing problems in different fields incredibly effectively. One important field that quantum computing has shown great results in machine learning. Until now, many different quantum algorithms have been presented to perform different machine learning approaches. In some special cases, the execution time of these quantum algorithms will be reduced exponentially compared to the classical ones. But at the same time, with increasing data volume and computation time, taking care of systems to prevent unwanted interactions with the environment can be a daunting task and since these algorithms work on machine learning problems, which usually includes big data, their implementation is very costly in terms of quantum resources. Here, in this paper, we have proposed an approach to reduce the cost of quantum circuits and to optimize quantum machine learning circuits in particular. To reduce the number of resources used, in this paper an approach including different optimization algorithms is considered. Our approach is used to optimize quantum machine learning algorithms for big data. In this case, the optimized circuits run quantum machine learning algorithms in less time than the original ones and by preserving the original functionality. Our approach improves the number of quantum gates by 10.7% and 14.9% in different circuits and the number of time steps is reduced by three and 15 units, respectively. This is the amount of reduction for one iteration of a given sub-circuit U in the main circuit. For cases where this sub-circuit is repeated more times in the main circuit, the optimization rate is increased. Therefore, by applying the proposed method to circuits with big data, both cost and performance are

关键词： Big data

On the probabilistic quantum error correction

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arXiv 2022年

作者： Kukulski, Ryszard Pawela, Lukasz Puchala, Zbigniew Institute of Theoretical and Applied Informatics Polish Academy of Sciences Baltycka 5 Gliwice44-100 Poland Faculty of Physics Astronomy and Applied Computer Science Jagiellonian University ul. Lojasiewicza 11 Kraków30-348 Poland

Probabilistic quantum error correction is an error-correcting procedure which uses postselection to determine if the encoded information was successfully restored. In this work, we deeply analyze probabilistic version of the error-correcting procedure for general noise. We generalized the Knill-Laflamme conditions for probabilistically correctable errors. We show that for some noise channels, we should encode the information into a mixed state to maximize the probability of successful error correction. Finally, we investigate an advantage of the probabilistic error-correcting procedure over the deterministic one. Reducing the probability of successful error correction allows for correcting errors generated by a broader class of noise channels. Significantly, if the errors are caused by a unitary interaction with an auxiliary qubit system, we can probabilistically restore a qubit state by using only one additional physical qubit. © 2022, CC BY.

关键词： Error correction

Class-Aware Patch Embedding Adaptation for Few-Shot Image Classification

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Class-Aware Patch Embedding Adaptation for Few-Shot Image Cl...

International Conference on computer Vision (ICCV)

作者： Fusheng Hao Fengxiang He Liu Liu Fuxiang Wu Dacheng Tao Jun Cheng Shenzhen Institute of Advanced Technology Guangdong-Hong Kong-Macao Joint Laboratory of Human-Machine Intelligence-Synergy Systems Chinese Academy of Sciences China The Chinese University of Hong Kong Hong Kong China AIAI School of Informatics University of Edinburgh United Kingdom School of Computer Science Faculty of Engineering The University of Sydney Australia

"A picture is worth a thousand words", significantly beyond mere a categorization. Accompanied by that, many patches of the image could have completely irrelevant meanings with the categorization if they were independently observed. This could significantly reduce the efficiency of a large family of few-shot learning algorithms, which have limited data and highly rely on the comparison of image patches. To address this issue, we propose a Class-aware Patch Embedding Adaptation (CPEA) method to learn "class-aware embeddings" of the image patches. The key idea of CPEA is to integrate patch embeddings with class-aware embeddings to make them class-relevant. Furthermore, we define a dense score matrix between class-relevant patch embeddings across images, based on which the degree of similarity between paired images is quantified. Visualization results show that CPEA concentrates patch embeddings by class, thus making them class-relevant. Extensive experiments on four benchmark datasets, miniImageNet, tieredImageNet, CIFAR-FS, and FC-100, indicate that our CPEA significantly outperforms the existing state-of-the-art methods. The source code is available at https://***/FushengHao/CPEA.

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ECHELONED SPACES

arXiv 2023年

作者： Gheysens, Maxime Pavlica, Bojana Pech, Christian Pech, Maja Schneider, Friedrich Martin Institute of Discrete Mathematics and Algebra Faculty of Mathematics and Computer Science Technische Universität Bergakademie Freiberg FreibergD-09596 Germany Department of Mathematics and Informatics University of Novi Sad Novi Sad21000 Serbia Institute of Mathematics Czech Academy of Sciences Žitná 25 Praha 1115 67 Czech Republic

We introduce the notion of echeloned spaces — an order-theoretic abstraction of metric spaces. The first step is to characterize metrizable echeloned spaces. It turns out that morphisms between metrizable echeloned spaces are uniformly continuous or have a uniformly discrete image. In particular, every automorphism of a metrizable echeloned space is uniformly continuous, and for every metric space with midpoints the automorphisms of the induced echeloned space are precisely the dilations. Next we focus on finite echeloned spaces. They form a Fraïssé class and we describe its Fraïssé-limit both as the echeloned space induced by a certain homogeneous metric space and as the result of a random construction. Building on this we show that the class of finite ordered echeloned spaces is Ramsey. The proof of this result combines a combinatorial argument by Nešetřil and Hubička with a topological-dynamical point of view due to Kechris, Pestov, and Todorčević. Finally, using the method of Katětov functors due to Kubiś and Mašulović, we prove that the full symmetric group on a countable set topologically embeds into the automorphism group of the countable universal homogeneous echeloned space. Copyright © 2023, The Authors. All rights reserved.

关键词： Topology

Proxy Design: A Method for Involving Proxy Users to Speak on Behalf of Vulnerable or Unreachable Users in Co-Design

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arXiv 2023年

作者： Islind, Anna Sigridur Lundin, Johan Cerna, Katerina Lindroth, Tomas Åkeflo, Linda Steineck, Gunnar Department of Computer Science Reykjavik University Reykjavik Iceland Department of Learning Communication and IT University of Gothenburg Gothenburg Sweden School of Information Technology Halmstad University Halmstad Sweden Department of Informatics University of Gothenburg Gothenburg Sweden Sahlgrenska University Hospital Gothenburg Sweden Division of Clinical Cancer Epidemiology Sahlgrenska Academy Gothenburg Sweden

Purpose: Designing digital artifacts is not a linear, straightforward process. This is particularly true when applying a user-centered design approach, or co-design, with users who are unable to participate in the design process. Although the reduced participation of a particular user group may harm the end result, the literature on solving this issue is sparse. In this article, proxy design is outlined as a method for involving a user group as proxy users to speak on behalf of a group that is difficult to reach. The article investigates the following research question: How can roleplaying be embedded in co-design to engage users as proxies on behalf of those who are unable to represent themselves? Method: The article presents a design ethnography spanning three years at a cancer rehabilitation clinic, where digital artifacts were designed to be used collaboratively by nurses and patients. The empirical data were analyzed using content analysis and consisted of 20 observation days at the clinic, six proxy design workshops, 21 telephone consultations between patients and nurses, and log data from the digital artifact. Findings: The article shows that simulated consultations, with nurses roleplaying as proxies for patients ignited and initiated the design process and enabled an efficient in-depth understanding of patients. Moreover, the article reveals how proxy design as a method further expanded the design. The study findings illustrate: (1) proxy design as a method for initiating design, (2) proxy design as an embedded element in co-design and (3) six design guidelines that should be considered when engaging in proxy design. Originality: The main contribution is the conceptualization of proxy design as a method that can ignite and initiate the co-design process when important users are unreachable, vulnerable or unable to represent themselves in the co-design process. More specifically, based on the empirical findings from a design ethnography that involved nurses

关键词： User centered design

Resource-efficient utilization of quantum computers

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arXiv 2023年

作者： Mohammad, Ijaz Ahamed Pivoluska, Matej Plesch, Martin Institute of Physics Slovak Academy of Sciences Dúbravská cesta 9 Bratislava841 04 Slovakia Institute of Computer Science Masaryk University Šumavská 416 Brno602 00 Czech Republic Faculty of Natural Sciences and Informatics Constantine the Philosopher University Tr. A. Hlinku 1 Nitra949 01 Slovakia

The current state of quantum computing is commonly described as the Noisy Intermediate-Scale Quantum era. Available computers contain a few dozens of qubits and can perform a few dozens of operations before the inevitable noise erases all information encoded in the calculation. Even if the technology advances fast within the next years, any use of quantum computers will be limited to short and simple tasks, serving as subroutines of more complex classical procedures. Even for these applications the resource efficiency, measured in the number of quantum computer runs, will be a key parameter. Here we suggest a general optimization procedure for hybrid quantum-classical algorithms that allows finding the optimal approach with limited quantum resources. We demonstrate this procedure on a specific example of variational quantum algorithm used to find the ground state energy of a hydrogen molecule. Copyright © 2023, The Authors. All rights reserved.

关键词： Qubits

Factor Analysis with Correlated Topic Model for Multi-Modal Data

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arXiv 2025年

作者： Lazęcka, Malgorzata Szczurek, Ewa Faculty of Mathematics Informatics and Mechanics University of Warsaw Institute of Computer Science Polish Academy of Sciences Poland Institute of AI for Health Helmholtz Center Munich Faculty of Mathematics Informatics and Mechanics University of Warsaw Poland

Integrating various data modalities brings valuable insights into underlying phenomena. Multimodal factor analysis (FA) uncovers shared axes of variation underlying different simple data modalities, where each sample is represented by a vector of features. However, FA is not suited for structured data modalities, such as text or single cell sequencing data, where multiple data points are measured per each sample and exhibit a clustering structure. To overcome this challenge, we introduce FACTM, a novel, multi-view and multi-structure Bayesian model that combines FA with correlated topic modeling and is optimized using variational inference. Additionally, we introduce a method for rotating latent factors to enhance interpretability with respect to binary features. On text and video benchmarks as well as real-world music and COVID-19 datasets, we demonstrate that FACTM outperforms other methods in identifying clusters in structured data, and integrating them with simple modalities via the inference of shared, interpretable factors. Copyright © 2025, The Authors. All rights reserved.

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