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Optimal demonstration of generalized quantum contextuality

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arXiv 2024年

作者： Hazra, Soumyabrata Saha, Debashis Chaturvedi, Anubhav Bera, Subhankar Majumdar, A.S. International Institute of Information Technology Gachibowli Hyderabad500032 India School of Physics Indian Institute of Science Education and Research Kerala Thiruvananthapuram695551 India Faculty of Applied Physics and Mathematics Gdańsk University of Technology Gabriela Narutowicza 11/12 Gdańsk80-233 Poland University of Gdańsk Gdańsk80-308 Poland S. N. Bose National Centre for Basic Sciences Block JD Sector III Salt Lake Kolkata700106 India

Finding a set of empirical criteria fulfilled by any theory that satisfies the generalized notion of noncontextuality is a challenging task of both operational and foundational importance. The conventional approach of deriving facet inequalities from the relevant noncontextual polytope is computationally demanding. Specifically, the noncontextual polytope is a product of two polytopes, one for preparations and the other for measurements, and the dimension of the former typically increases polynomially with the number of measurements. This work presents an alternative methodology for constructing a polytope that encompasses the actual noncontextual polytope while ensuring that the dimension of the polytope associated with the preparations remains constant regardless of the number of measurements and their outcome size. In particular, the facet inequalities of this polytope serve as necessary conditions for noncontextuality. To demonstrate the efficacy of our methodology, we apply it to nine distinct contextuality scenarios involving four to nine preparations and two to three measurements to obtain the respective sets of facet inequalities. Additionally, we retrieve the maximum quantum violations of these inequalities. Our investigation uncovers many novel non-trivial noncontextuality inequalities and reveals intriguing aspects and applications of quantum contextual correlations. Copyright © 2024, The Authors. All rights reserved.

关键词： Quantum theory

Industrial Wastewater Management using Blockchain technology: Architecture, Requirements, and Future Directions

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IEEE Internet of Things Magazine 2020年第2期3卷 38-43页

作者： Hakak, Saqib Khan, Wazir Zada Gilkar, Gulshan Amin Haider, Noman Imran, Muhammad Alkatheiri, M. Saeed University of Northern British Columbia Canada Farasan Networking Research Laboratory Faculty of Cs and Is Jazan University Saudi Arabia College of Computer Science and Information Technology Shaqra University Saudi Arabia College of Applied Computer Science King Saud University Saudi Arabia Victoria University Sydney Australia Department of Cybersecurity College of Cs and Engineering University of Jeddah Saudi Arabia

The inefficient disposal of industrial waste causes water and soil pollution;thus, to protect the health of different ecosystems, industrial wastewater management is essential. Wastewater treatment's aim is to clean and protect water and to extract pollutants and remove toxicants before the remaining water is discharged into the environment. Currently, the disposal of industrial wastewater is an important topic because of the serious threat of wastewater to aquatic life and surrounding environment. Therefore, wastewater must be effectively treated and safely discharged into water bodies. In this study, for industrial wastewater management, we aim to use blockchain technology. Thus, we propose a conceptual architecture based on blockchain and present three case studies. Subsequently, we discussed requirements for incorporating blockchain into wastewater management. Finally, we demonstrated directions for future work. © 2018 IEEE.

关键词： Blockchain

Ions-induced Epitaxial Growth of Perovskite Nanocomposites for Highly Efficient Light-Emitting Diodes with EQE Exceeding 30%

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arXiv 2023年

作者： Xing, Zhaohui Jin, Guangrong Du, Qing Pang, Peiyuan Liu, Tanghao Shen, Yang Zhang, Dengliang Yu, Bufan Liang, Yue Yang, Dezhi Tang, Jianxin Wang, Lei Xing, Guichuang Chen, Jiangshan Ma, Dongge Institute of Polymer Optoelectronic Materials and Devices State Key Laboratory of Luminescent Materials and Devices Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates South China University of Technology Guangzhou510640 China Joint Key Laboratory of the Ministry of Education Institute of Applied Physics and Materials Engineering University of Macau Macau999078 China Faculty of Innovation Engineering Macau University of Science and Technology Macau Taipa999078 China Wuhan National Laboratory for Optoelectronics Huazhong University of Science and Technology Wuhan430074 China

Metal halide perovskites, a class of cost-effective semiconductor materials, are of great interest for modern and upcoming display technologies that prioritize the light-emitting diodes (LEDs) with high efficiency and excellent color purity. The prevailing approach to achieving efficient luminescence from pervoskites is enhancing exciton binding effect and confining carriers by reducing their dimensionality or grain size. However, splitting pervoskite lattice into smaller ones generates abundant boundaries in solid films and results in more surface trap states, needing exact passivation to suppress trap-assisted nonradiative losses. Here, an ions-induced heteroepitaxial growth method is employed to assembe perovskite lattices with different structures into large-sized grains to produce lattice-anchored nanocomposites for efficient LEDs with high color purity. This approach enables the nanocomposite thin films, composed of three-dimensional (3D) CsPbBr3 and its variant of zero-dimensional (0D) Cs4PbBr6, to feature significant low trap-assisted nonradiative recombination, enhanced light out-coupling with a corrugated surface, and well-balanced charge carrier transport. Based on the resultant 3D/0D perovskite nanocomposites, we demonstrate the perovskite LEDs achieving an remarkable external quantum efficiency of 31.0% at the emission peak of 521 nm with a narrow full width at half-maximum of only 18 nm. This research introduces a novel approach to the development of well-assembled nanocomposites for perovskite LEDs, demonstrating high efficiency comparable to that of state-of-the-art organic LEDs. Copyright © 2023, The Authors. All rights reserved.

关键词： Perovskite

COMPUTABLE PARADOXICAL DECOMPOSITIONS

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arXiv 2022年

作者： Duda, Karol Ivanov, Aleksander Faculty of Mathematics and Computer Science University of Wroc law pl. Grunwaldzki 2 Wroclaw50-384 Poland Department of Applied Mathematics Silesian University of Technology ul. Kaszubska 23 Gliwice44-100 Poland

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Small polarons mediated near-room-temperature metal-insulator transition in vanadium dioxide and their hopping dynamics

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arXiv 2023年

作者： Liu, Xiongfang Yang, Tong Chen, Shanquan Wu, Jing Tang, Chi Sin Ning, Yuanjie Chen, Zuhuang Dai, Liang Sun, Mengxia Chen, Mingyao Han, Kun Zhou, Difan Zeng, Shengwei Sun, Shuo Li, Sensen Yang, Ming Breese, Mark B.H. Cai, Chuanbing Venkatesan, Thirumalai Wee, Andrew T.S. Yin, Xinmao Shanghai Key Laboratory of High Temperature Superconductors Institute for Quantum Science and Technology Department of Physics Shanghai University Shanghai200444 China Department of Applied Physics The Hong Kong Polytechnic University Kowloon100872 Hong Kong School of Materials Science and Engineering Harbin Institute of Technology Shenzhen518055 China 2 Fusionopolis Way Innovis #08-03 Singapore138634 Singapore National University of Singapore Singapore117603 Singapore Information Materials and Intelligent Sensing Laboratory of Anhui Province Institutes of Physical Science and Information Technology Anhui University Hefei230601 China Department of Electronic Engineering School of Electronic Science and Engineering Xiamen University Xiamen361005 China Department of Physics Faculty of Science National University of Singapore Singapore117542 Singapore Center for Quantum Research and Technology University of Oklahoma NormanOK73019 United States Centre for Advanced 2D Materials and Graphene Research National University of Singapore Singapore117546 Singapore

Researchers pursuing advanced photoelectric devices have discovered near room-temperature metal-insulator transitions (MIT) in non-volatile VO2. Despite theoretical investigations suggesting that polaron dynamics mediate the MIT, direct experimental evidence remains scarce. In this study, we present direct evidence of the polaron state in insulating VO2 through high-resolution spectroscopic ellipsometry measurements and first-principles calculations. We illustrate the complementary role of polaron dynamics in facilitating Peierls and Mott transitions, thereby contributing to the MIT processes. Furthermore, our observations and characterizations of conventional metallic and correlated plasmons in the respective phases of the VO2 film offer valuable insights into their electron structures. This investigation enhances comprehension of the MIT mechanism in correlated systems and underscores the roles of polarons, lattice distortions, and electron correlations in facilitating phase transition processes in strongly-correlated systems. Additionally, the detailed detection of small polarons and plasmons serves as inspiration for the development of new device functionalities. Copyright © 2023, The Authors. All rights reserved.

关键词： Vanadium dioxide

Hinge modes and surface states in second-order topological three-dimensional quantum Hall systems induced by charge density modulation

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Physical Review B 2020年第12期102卷 125126-125126页

作者： Paweł Szumniak Daniel Loss Jelena Klinovaja AGH University of Science and Technology Faculty of Physics and Applied Computer Science al. Mickiewicza 30 30-059 Kraków Poland Department of Physics University of Basel Klingelbergstrasse 82 4056 Basel Switzerland

We consider a system of weakly coupled one-dimensional wires forming a three-dimensional stack in the presence of a spatially periodic modulation of the chemical potential along the wires, equivalent to a charge density wave (CDW). An external static magnetic field is applied parallel to the wire axes. We show that, for a certain parameter regime, due to interplay between the CDW and magnetic field, the system can support a second-order topological phase characterized by the presence of chiral quasi-1D quantum Hall effect (QHE) hinge modes. Interestingly, we demonstrate that direction of propagation of the hinge modes depends on the phase of the CDW and can be reversed only by electrical means without the need of changing the orientation of the magnetic field. Furthermore, we show that the system can also support 2D chiral surface QHE states, which can coexist with one-dimensional hinge modes, realizing a scenario of a hybrid high-order topology. Performing two-terminal transport simulations in the linear response regime, we confirm quantized QHE resistance plateaus, which are highly robust to disorder giving a clear signature of hinge and surface states.

关键词： Edge states Hall effect Topological materials

Structural analysis of high-pressure phase for skyrmion-hosting multiferroic Cu2OSeO3

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Physical Review B 2020年第20期102卷 201106(R)-201106(R)页

作者： E. Nishibori S. Karatsu C. Terakura N. Takeshita M. Kinoshita S. Ishiwata Y. Tokura S. Seki Faculty of Pure and Applied Sciences and Tsukuba Research Center for Energy Materials Science (TREMS) University of Tsukuba Tsukuba 305-8571 Japan RIKEN Center for Emergent Matter Science (CEMS) Wako 351-0198 Japan National Institute of Advanced Industrial Science and Technology (AIST) Tsukuba Ibaraki 305-8562 Japan Department of Applied Physics University of Tokyo Tokyo 113-8656 Japan Division of Materials Physics Graduate School of Engineering Science Osaka University Osaka 560-8531 Japan Tokyo College University of Tokyo Tokyo 113-8656 Japan Institute of Engineering Innovation University of Tokyo Tokyo 113-8656 Japan PRESTO Japan Science and Technology Agency (JST) Kawaguchi 332-0012 Japan

Cu2OSeO3 is known as a unique example of insulating multiferroic compounds with a skyrmion spin texture, which is characterized by a chiral cubic crystal structure at ambient pressure. Recently, it has been reported that this compound shows a pressure-induced structural transition with a large enhancement of magnetic ordering temperature. In the present Rapid Communication, we have investigated the detailed crystal structure in the high-pressure phase, by combining a synchrotron x-ray diffraction experiment with a diamond anvil cell and an analysis based on the genetic algorithm. Our results suggest that the original pyrochlore Cu network is sustained even after the structural transition, while the orientation of the SeO3 molecule as well as the position of oxygen in the middle of the Cu tetrahedra are significantly modified. The latter features may be the key for the reported enhancement of Tc and the associated stabilization of the skyrmion phase at room temperature.

关键词： Crystal structure Skyrmions Structural phase transition Structural properties Multiferroics Pressure techniques X-ray diffraction

On a Problem of Steinhaus

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arXiv 2021年

作者： Anholcer, Marcin Bosek, Bartlomiej Grytczuk, Jaroslaw Gutowski, Grzegorz Przybylo, Jakub Pyzik, Rafal Zając, Mariusz Institute of Informatics and Electronic Economics Poznań University of Economics and Business Poznań Poland Institute of Theoretical Computer Science Faculty of Mathematics and Computer Science Jagiellonian University Kraków Poland Faculty of Mathematics and Information Science Warsaw University of Technology Warsaw Poland AGH University of Science and Technology Faculty of Applied Mathematics al. A. Mickiewicza 30 Kraków30-059 Poland

Let N be a positive integer. A sequence X = (x1, x2, . . ., xN) of points in the unit interval [0, 1) is piercing if {x1, x2, . . ., xN}∩[i/n, i+1/n) ≠ ∅ holds for every n = 1, 2, . . ., N and every i = 0, 1, . . ., n−1. In 1958 Steinhaus asked whether piercing sequences can be arbitrarily long. A negative answer was provided by Schinzel, who proved that any such sequence may have at most 74 elements. This was later improved to the best possible value of 17 by Warmus, and independently by Berlekamp and Graham. In this paper we study a more general variant of piercing sequences. Let f(n) ≥ n be an infinite nondecreasing sequence of positive integers. A sequence X = (x1, x2, . . ., xf(N)) is f-piercing if {x1, x2, . . ., xf(N)} ∩ [i/n, i+1/n) ≠ ∅ holds for every n = 1, 2, . . ., N and every i = 0, 1, . . ., n − 1. A special case of f(n) = n + d, with d a fixed nonnegative integer, was studied by Berlekamp and Graham. They noticed that for each d ≥ 0, the maximum length of any (n + d)-piercing sequence is finite. Expressing this maximum length as s(d) + d, they obtained an exponential upper bound on the function s(d), which was later improved to s(d) = O(d3) by Graham and Levy. Recently, Konyagin proved that 2d ≤ s(d) 1d⌋ ≤ s(d) ≤ c2d + o(d) where c1 = ln 2/1-ln 2 ≈ 2.25 and c2 = 1+ln 2/1-ln 2 ≈ 5.52. We also prove that there exists an infinite f-piercing sequence with f(n) = γn + o(n) if and only if γ ≥ 1/ln 2 ≈ 1.44. © 2021, CC BY-SA.

关键词： Piercing

On a Cyclometric Modification of the Chua System

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On a Cyclometric Modification of the Chua System

International IEEE Conference and Workshop: Óbuda on Electrical and Power Engineering (CANDO-EPE)

作者： Bálint Nagy Antal Joós Attila Kovari Department of Mathematics Institute of Computer Engineering University of Dunaujvaros Dunaujvaros Hungary Department of Natural Sciences Kandó Kálmán Faculty of Electrical Engineering Institute of Electrophysics Obuda University Budapest Hungary Department of Applied Quantitative Methods Faculty of Finance and Accountancy Budapest Business University Budapest Hungary Kandó Kálmán Faculty of Electrical Engineering Institute of Electronics and Communication Systems Obuda University Budapest Hungary Faculty of Computer Science Institute of Digital Technology Eszterházy Károly Catholic University Eger Hungary Department of Natural Sciences Institute of Engineering University of Dunaújváros Dunaujvaros Hungary GAMF Faculty of Engineering and Computer Science John Von Neumann University Kecskemét Hungary

Chaos is not only a unique chapter in the theory of dynamical systems but also a useful one with many applications in the field of communications. In this work a cyclometric modification of the well-known example of chaotic systems, the modified differential equations describing the behavior of the Chua-circuit is investigated. The results obtained can be applied in the encryption methods of the implementation of different communication channels like machine-machine or cognitive one.

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