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Transactions of the korean institute of Electrical Engineers 2021年第11期70卷 1750-1758页

作者： Jo, Jang-Hoon Bang, Junho Yoo, Jung-Hoon Sun, Robin Hong, Seong-Jun Bang, Sun-Bea Division of Convergence Technology Engineering Department of Energy Conversion Engineering of Graduate School Jeonbuk National University Korea Republic of Dept.of IT Applied Engineering Jeonbuk National University Jeonju Korea Republic of Department of Energy Conversion Engineering of Graduate School Jeonbuk National University Jeonju Korea Republic of Dept. of Safety Research Department Researcher Electrical Safety Research Institute Korea Republic of

In this paper, a new CNN algorithm is proposed to determine the direct cause of electric fires. We create 10,000-15,000 three types of data that can occur at a fire scene in our laboratory, and then train and verify it through the proposed CNN algorithm. As a result of the experiment and analysis, the classification accuracy of the primary and secondary arc beads was 86.2%, the accuracy of arc beads and molten marks was 93.6%. And also, the classification accuracy of the primary and secondary arc beads and molten marks was 92.4%. The results of this study are meaningful in that fire forensics can provide accurate identification results in a shorter time through artificial intelligence algorithms compared to the existing methods of identification through visual classification and physicochemical material analysis methods. In particular, the classification between primary and secondary arc beads is known to be a very difficult problem. However, the results of this study provided more than 86% classification ability. © 2021 korean institute of Electrical Engineers. All rights reserved.

关键词： Fires

Dipole condensates in tilted Bose-Hubbard chains

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arXiv 2022年

作者： Lake, Ethan Lee, Hyun-Yong Han, Jung Hoon Senthil, T. Department of Physics Massachusetts Institute of Technology CambridgeMA02139 United States Division of Display and Semiconductor Physics Korea University Sejong30019 Korea Republic of Department of Applied Physics Graduate School Korea University Sejong30019 Korea Republic of Interdisciplinary Program in E·ICT-Culture-Sports Convergence Korea University Sejong30019 Korea Republic of Department of Physics Sungkyunkwan University Suwon16419 Korea Republic of

We study the quantum phase diagram of a Bose-Hubbard chain whose dynamics conserves both boson number and boson dipole moment, a situation which can arise in strongly tilted optical lattices. The conservation of dipole moment has a dramatic effect on the phase diagram, which we analyze by combining a field theory analysis with DMRG simulations. In the thermodynamic limit, the phase diagram is dominated by various types of incompressible dipolar condensates. In finite-sized systems however, it may be possible to stabilize a 'Bose-Einstein insulator': an exotic compressible phase which is insulating, despite the absence of a charge gap. We suggest several ways by which these exotic phases can be identified in near-term cold atom experiments. © 2022, CC BY.

关键词： Bosons

Thermal Hall Effects of Spins and Phonons in Kagome Antiferromagnet Cd-Kapellasite

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Physical Review X 2020年第4期10卷 041059-041059页

作者： Masatoshi Akazawa Masaaki Shimozawa Shunichiro Kittaka Toshiro Sakakibara Ryutaro Okuma Zenji Hiroi Hyun-Yong Lee Naoki Kawashima Jung Hoon Han Minoru Yamashita The Institute for Solid State Physics The University of Tokyo Kashiwa 277-8581 Japan Graduate School of Engineering Science Osaka University Toyonaka 560-8531 Japan Department of Physics Chuo University Kasuga Bunkyo-ku Tokyo 112-8551 Japan Okinawa Institute of Science and Technology Graduate University Kunigami-gun 904-0495 Japan Department of Applied Physics Graduate School Korea University Sejong 30019 Korea Division of Display and Semiconductor Physics Korea University Sejong 30019 Korea Interdisciplinary Program in E·ICT-Culture-Sports Convergence Korea University Sejong 30019 Korea Department of Physics Sungkyunkwan University Suwon 16419 Korea

We investigate the thermal-transport properties of the kagome antiferromagnet Cd-kapellasite (Cd-K). We find that a field-suppression effect on the longitudinal thermal conductivity κxx sets in below approximately 25 K. This field-suppression effect at 15 T becomes as large as 80% at low temperatures, suggesting a large spin contribution κxxsp in κxx. We also find clear thermal Hall signals in the spin liquid phase in all Cd-K samples. The magnitude of the thermal Hall conductivity κxy shows a significant dependence on the sample’s scattering time, as seen in the rise of the peak κxy value in almost linear fashion with the magnitude of κxx. On the other hand, the temperature dependence of κxy is similar in all Cd-K samples; κxy shows a peak at almost the same temperature of the peak of the phonon thermal conductivity κxxph which is estimated by κxx at 15 T. These results indicate the presence of a dominant phonon thermal Hall κxyph at 15 T. In addition to κxyph, we find that the field dependence of κxy at low fields turns out to be nonlinear at low temperatures, concomitantly with the appearance of the field suppression of κxx, indicating the presence of a spin thermal Hall κxysp at low fields. Remarkably, by assembling the κxx dependence of κxysp data of other kagome antiferromagnets, we find that, whereas κxysp stays a constant in the low-κxx region, κxysp starts to increase as κxx does in the high-κxx region. This κxx dependence of κxysp indicates the presence of both intrinsic and extrinsic mechanisms in the spin thermal Hall effect in kagome antiferromagnets. Furthermore, both κxyph and κxysp disappear in the antiferromagnetic ordered phase at low fields, showing that phonons alone do not exhibit the thermal Hall effect. A high field above approximately 7 T induces κxyph, concomitantly with a field-induced increase of κxx and the specific heat, suggesting a coupling of the phonons to the field-induced spin excitations as the origin of κxyph.

关键词： Frustrated magnetism Spin liquid Thermal Hall effect Thermal conductivity

Cubic ferromagnet and emergent U(1) symmetry on its phase boundary

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Physical Review B 2023年第22期107卷 224406-224406页

作者： Wei-Lin Tu Xinliang Lyu S. R. Ghazanfari Huan-Kuang Wu Hyun-Yong Lee Naoki Kawashima Division of Display and Semiconductor Physics Korea University Sejong 30019 Korea Faculty of Science and Technology Keio University 3-14-1 Hiyoshi Kohoku-ku Yokohama 223-8522 Japan Institute for Solid State Physics University of Tokyo Kashiwa Chiba 277-8581 Japan Department of Physics Condensed Matter Theory Center and Joint Quantum Institute University of Maryland College Park Maryland 20742 USA Department of Applied Physics Graduate School Korea University Sejong 30019 Korea Interdisciplinary Program in E.ICT-Culture-Sports Convergence Korea University Sejong 30019 Korea Trans-scale Quantum Science Institute The University of Tokyo Bunkyo Tokyo 113-0033 Japan

We study the simplest quantum lattice spin model for the two-dimensional (2D) cubic ferromagnet by means of mean-field analysis and tensor network calculation. While both methods give rise to similar results in detecting related phases, the 2D infinite projected entangled-pair state (iPEPS) calculation provides more accurate values of transition points. Near the phase boundary, moreover, our iPEPS results indicate that it is more difficult to pin down the orientation of magnetic easy axes, and we interpret it as the easy-axis softening. This phenomenon implies an emergence of continuous U(1) symmetry, which is indicated by the low-energy effective model and has been analytically shown by the field theory. Our model and study provide a concrete example for utilizing iPEPS near the critical region, showing that the emergent phenomenon living on the critical points can already be captured by iPEPS with a rather small bond dimension.

关键词： Magnetic anisotropy Magnetism Quantum criticality Projected entangled pair states Tensor network methods

Metamaterial perfect absorber analyzed by a metacavity model consisting of multilayer metasurfaces

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arXiv 2017年

作者： Bhattarai, Khagendra Silva, Sinhara Song, Kun Urbas, Augustine Lee, Sang Jun Ku, Zahyun Zhou, Jiangfeng Department of Physics University of South Florida Tampa33620 United States Department of Applied Physics Smart Materials Laboratory Northwestern Polytechnical University Xi'an710129 China Air Force Research Laboratory Wright-Patterson Afb 45433 United States Korea Research Institute of Standards and Science Division of Convergence Technology Daejeon34113 Korea Republic of

We demonstrate that the metamaterial perfect absorber behaves as a meta-cavity bounded between a resonant metasurface and a metallic thin-film reflector. The perfect absorption is achieved by the Fabry-Perot cavity resonance via multiple reflections between the "quasi-open" boundary of resonator and the "closed" boundary of reflector. The characteristic features including angle independence, ultra-thin thickness and strong field localization can be well explained by this model. With this model, metamaterial perfect absorber can be redefined as a meta-cavity exhibiting high Q-factor, strong field enhancement and extremely high photonic density of states, thereby promising novel applications for high performance sensor, infrared photodetector and cavity quantum electrodynamics devices. Copyright © 2017, The Authors. All rights reserved.

关键词： Reflection

Novel Pluronic Polymer-Coated Carbon Black Nanoparticles as Highly Stable and Safe Biocompatible Black Tattoo Pigments

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SSRN

SSRN 2024年

作者： Oh, Hyeryeon Lee, Jin Sil Son, Panmo Ryu, Hyeonyeol Kim, On Beol Choi, Won Il Center for Bio-Healthcare Materials Bio-Convergence Materials R&D Division Korea Institute of Ceramic Engineering and Technology 202 Osongsaengmyeong 1-ro Osong-eup Heungdeok-gu Chungbuk Cheongju28160 Korea Republic of School of Materials Science and Engineering Gwangju Institute of Science and Technology 123 Cheomdan-gwagiro Buk-gu Gwangju61005 Korea Republic of Department of Applied Bioengineering Graduate School of Convergence Science and Technology Seoul National University Seoul08826 Korea Republic of Korea Conformity Laboratories 8 Gaetbeol-ro 145 beon-gil Yeonsu-gu Incheon21999 Korea Republic of Gbionic Corp. 101-1204 Harmony-ro Yeonsu-gu Incheon144 Korea Republic of

The tattoo industry has evolved in recent decades with the increasing prevalence of tattooing. However, developing ink components, specifically pigments with adequate stability and biocompatibility under physiological conditions, remains challenging. In this study, to develop safe pigments for tattoo inks, carbon black (CB) has been stabilized with different types of Pluronic polymers and characterized in vitro and in vivo. The effects of the polymer templates on the preparation, morphology, and properties of Pluronic-coated carbon black nanoparticles (CB/Plu NPs) have been investigated and optimized using various analytical techniques. In particular, CB/Plu NPs with PF127 at a weight ratio of 1:5 exhibit a high coating yield and dispersion stability. CB/Plu NPs with PF127 have a spherical morphology with uniform sizes of 158 nm and do not cause any cytotoxic effect, cellular morphological changes, or oxidative stress in vitro. Intradermally injected CB/Plu NPs maintain an intense black color for 16 weeks without causing histological changes in the isolated dorsal skin of rats. Our results suggest that aqueous dispersions of CB/Plu NPs can be used as black tattoo inks exhibiting enhanced stability and safety. © 2024, The Authors. All rights reserved.

关键词： Nanoparticles

Aspects of N rank-2 gauge theory in (2 + 1)D: construction schemes, holonomies, and sublattice one-form symmetries

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arXiv 2023年

作者： Oh, Yun-Tak Pace, Salvatore D. Han, Jung Hoon You, Yizhi Lee, Hyun-Yong Division of Display and Semiconductor Physics Korea University Sejong30019 Korea Republic of Department of Physics Massachusetts Institute of Technology CambridgeMA02139 United States Department of Physics Sungkyunkwan University Suwon16419 Korea Republic of Department of Physics Northeastern University 360 Huntington Ave BostonMA02115 United States Department of Applied Physics Graduate School Korea University Sejong30019 Korea Republic of Interdisciplinary Program in E·ICT-Culture-Sports Convergence Korea University Sejong30019 Korea Republic of

Rank-2 toric code (R2TC), a prototypical archetype of the discrete rank-2 symmetric gauge theory, has properties that differ from those of the standard toric code. Specifically, it features a blending of UV and IR in its ground state, restricted mobility of its quasiparticles, and variations in the braiding statistics of its quasiparticles based on their position. In this paper, we investigate various aspects of N rank-2 gauge theory in (2 + 1)-dimensional spacetime. Firstly, we demonstrate that U(1) rank-2 gauge theory can arise from U(1) × U(1) rank-1 gauge theory after condensing the gauge charges in a specific way. This construction scheme of U(1) rank-2 gauge theory carries over to the N case simply by Higgsing U(1) to N, after which the resulting rank-2 gauge theory can be tuned to the R2TC. The holonomy operators of R2TC are readily identified using this scheme and are given clear physical interpretation as the pair creation/annihilation of various monopoles and dipoles. Explicit tensor network construction of the ground states of R2TC are given as two copies of the ground states of Kitaev’s toric code that are ‘sewn together’ according to the condensation scheme. In addition, through a similar anyon condensation protocol, we present a double semion version of rank-2 toric code whose flux excitations exhibit restricted mobility and semionic statistics. Finally, we identify the generalized discrete symmetries of the R2TC, which are much more complex than typical 1-form symmetries. They include conventional and unconventional 1-form symmetries, such as framed 1-form symmetries and what we call sublattice 1-form symmetries. Using these, we interpret the R2TC’s unique properties (UV/IR mixing, position-dependent braiding, etc.) from the modern perspective of generalized spontaneous symmetry breaking and’t Hooft anomalies. © 2023, CC BY.

关键词： Ground state

Entanglement properties of disordered quantum spin chains with long-range antiferromagnetic interactions

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Physical Review B 2020年第21期102卷 214201-214201页

作者： Y. Mohdeb J. Vahedi N. Moure A. Roshani Hyun-Yong Lee R. N. Bhatt Stefan Kettemann Stephan Haas Department of Physics and Earth Sciences Jacobs University Bremen Bremen 28759 Germany Technische Universität Braunschweig Institut für Mathematische Physik Mendelssohnstr. 3 38106 Braunschweig Germany Department of Physics Sari Branch Islamic Azad University Sari 48164-194 Iran Department of Physics and Astronomy University of Southern California Los Angeles California 90089-0484 USA Department of Applied Physics Graduate School Korea University Sejong 30019 Korea Division of Display and Semiconductor Physics Korea University Sejong 30019 Korea Interdisciplinary Program in EċICT-Culture-Sports Convergence Korea University Sejong 30019 Korea Department of Electrical Engineering Princeton University Princeton New Jersey 08544 USA School of Natural Sciences Institute for Advanced Study Princeton New Jersey 08540 USA Division of Advanced Materials Science Pohang University of Science and Technology (POSTECH) Pohang 790-784 Korea

Entanglement measures are useful tools in characterizing otherwise unknown quantum phases and indicating transitions between them. Here we examine the concurrence and entanglement entropy in quantum spin chains with random long-range couplings, spatially decaying with a power-law exponent α. Using the strong disorder renormalization group (SDRG) technique, we find by analytical solution of the master equation a strong disorder fixed point, characterized by a fixed point distribution of the couplings with a finite dynamical exponent, which describes the system consistently in the regime α>12. A numerical implementation of the SDRG method yields a power-law spatial decay of the average concurrence, which is also confirmed by exact numerical diagonalization. However, we find that the lowest-order SDRG approach is not sufficient to obtain the typical value of the concurrence. We therefore implement a correction scheme which allows us to obtain the leading-order corrections to the random singlet state. This approach yields a power-law spatial decay of the typical value of the concurrence, which we derive both by a numerical implementation of the corrections and by analytics. Next, using numerical SDRG, the entanglement entropy (EE) is found to be logarithmically enhanced for all α, corresponding to a critical behavior with an effective central charge c=ln(2), independent of α. This is confirmed by an analytical derivation. Using numerical exact diagonalization (ED), we confirm the logarithmic enhancement of the EE and a weak dependence on α. For a wide range of partition size l, the EE fits a critical behavior with a central charge close to c=1, which is the same as for the clean Haldane-Shastry model with a power-law-decaying interaction with α=2. Only for small l≪L, in a range which increases with the number of spins N, we find deviations which are rather consistent with the strong disorder fixed point central charge c=ln(2). Furthermore, we find using ED that the conc

关键词： Magnetism Quantum entanglement Disordered systems Doped semiconductors Density matrix methods Exact diagonalization Renormalization group Tensor network methods

Cubic ferromagnet and emergent U(1) symmetry on its phase boundary

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arXiv 2022年

作者： Tu, Wei-Lin Lyu, Xinliang Ghazanfari, S.R. Wu, Huan-Kuang Lee, Hyun-Yong Kawashima, Naoki Division of Display and Semiconductor Physics Korea University Sejong30019 Korea Republic of Faculty of Science and Technology Keio University 3-14-1 Hiyoshi Kohoku-ku Yokohama223-8522 Japan Institute for Solid State Physics University of Tokyo Chiba Kashiwa277-8581 Japan Department of Physics Condensed Matter Theory Center Joint Quantum Institute University of Maryland College ParkMD20742 United States Department of Applied Physics Graduate School Korea University Sejong30019 Korea Republic of Interdisciplinary Program in E·ICT-Culture-Sports Convergence Korea University Sejong30019 Korea Republic of Trans-scale Quantum Science Institute The University of Tokyo Bunkyo Tokyo113-0033 Japan

关键词： Quantum entanglement

Generating Function for Projected Entangled-Pair States

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PRX Quantum 2024年第1期5卷 010335-010335页

作者： Wei-Lin Tu Laurens Vanderstraeten Norbert Schuch Hyun-Yong Lee Naoki Kawashima Ji-Yao Chen Faculty of Science and Technology Keio University 3-14-1 Hiyoshi Kohoku-ku Yokohama 223-8522 Japan Center for Nonlinear Phenomena and Complex Systems Université Libre de Bruxelles B-1050 Bruxelles Belgium University of Vienna Faculty of Physics Boltzmanngasse 5 Wien 1090 Austria University of Vienna Faculty of Mathematics Oskar-Morgenstern-Platz 1 Wien 1090 Austria Division of Display and Semiconductor Physics Korea University Sejong 30019 Korea Department of Applied Physics Graduate School Korea University Sejong 30019 Korea Interdisciplinary Program in E·ICT-Culture-Sports Convergence Korea University Sejong 30019 Korea Institute for Solid State Physics The University of Tokyo Kashiwa Chiba 277-8581 Japan Trans-scale Quantum Science Institute The University of Tokyo Bunkyo Tokyo 113-0033 Japan Center for Neutron Science and Technology Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices School of Physics Sun Yat-sen University Guangzhou 510275 China

Diagrammatic summation is a common bottleneck in modern applications of projected entangled-pair states, especially in computing low-energy excitations of a two-dimensional quantum many-body system. To solve this problem, here we extend the generating-function approach for tensor-network diagrammatic summation, a scheme previously proposed in the context of matrix product states. Taking the form of a one-particle excitation, we show that the excited state can be computed efficiently in the generating-function formalism, which can further be used in evaluating the dynamical structure factor of the system. Our benchmark results for the spin-1/2 transverse-field Ising model and Heisenberg model on the square lattice provide a desirable accuracy, showing good agreement with known results. We then study the spin-1/2J1-J2 model on the same lattice and investigate the dynamical properties of the putative gapless spin liquid phase. We conclude with a discussion on generalizations to multiparticle excitations.

关键词： Quasiparticles & collective excitations Quantum many-body systems Quantum spin models Strongly correlated systems Many-body techniques Projected entangled pair states Tensor network methods