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arXiv 2023年

作者： Ma, Chen-Te Department of Physics and Astronomy Iowa State University AmesIA50011 United States Asia Pacific Center for Theoretical Physics Pohang University of Science and Technology Gyeongsangbuk-do Pohang37673 Korea Republic of Guangdong Provincial Key Laboratory of Nuclear Science Institute of Quantum Matter South China Normal University Guangdong Guangzhou510006 China School of Physics and Telecommunication Engineering South China Normal University Guangdong Guangzhou510006 China Guangdong-Hong Kong Joint Laboratory of Quantum Matter Southern Nuclear Science Computing Center South China Normal University Guangzhou510006 China The Laboratory for Quantum Gravity and Strings Department of Mathematics and Applied Mathematics University of Cape Town Private Bag Rondebosch7700 South Africa

We review the various aspects of the 3D Einstein gravity theory with a negative cosmological constant and its boundary description. We also explore its connections to CFTs, modular symmetry, and holography. It is worth noting that this particular theory is topological in nature, which means that all the physical degrees of freedom are located on the boundary. Additionally, we can derive the boundary description on a torus, which takes the form of a 2D Schwarzian theory. This observation suggests that the relevant degrees of freedom for the theory can be described using this 2D theory. Because of the renormalizability of the 3D gravity theory, one can probe the quantum regime. This suggests that it is possible to investigate quantum phenomena. Unlike the conventional CFTs, when considering the AdS3 background, the boundary theory loses modular symmetry. This represents a departure from the usual behavior of CFT and is quite intriguing. The Weyl transformation induces anomaly in CFTs, and we indicate that applying this transformation to the 2D Schwarzian theory leads to similar results. Summing over all geometries with the asymptotic AdS3 boundary condition is equivalent to summing over a modular group. The partition function is one-loop exact and therefore an analytical expression from the summation. This theory holds potential applications in Quantum Information and is a recurring theme in the study of holography, where gravitational theories are connected with CFTs. Copyright © 2023, The Authors. All rights reserved.

关键词： Holography

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From High-Entropy Alloys to High-Entropy Ceramics: The Radiation-Resistant Highly Concentrated Refractory Carbide (CrNbTaTiW)C

SSRN

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SSRN 2023年

作者： Tunes, Matheus Araujo Fritze, Stefan Osinger, Barbara Willenshofer, Patrick Alvarado, Andrew M. Martinez, Enrique Menon, Ashok S. Ström, Petter Greaves, Graeme Lewin, Erik Jansson, Ulf Pogatscher, Stefan Saleh, Tarik A. Vishnyakov, Vladimir M. El-Atwani, Osman Materials Science and Technology Division Los Alamos National Laboratory Los AlamosNM87545 United States Department of Chemistry Angstrom Laboratory Uppsala University UppsalaSE-751 21 Sweden Department of Physics and Astronomy Applied Nuclear Physics Uppsala University UppsalaSE-751 21 Sweden Theoretical Division Los Alamos National Laboratory Los AlamosNM87545 United States Department of Materials Science and Engineering Clemson University ClemsonSC29623 United States Department of Mechanical Engineering Clemson University ClemsonSC29623 United States Chair of Non-Ferrous Metallurgy Montanuniversität Leoben8700 Austria School of Computing and Engineering University of Huddersfield HuddersfieldHD1 3DH United Kingdom

High-entropy materials represent the state-of-the-art on the alloy design strategy for future applications in extreme environments. Recent data indicates that high-entropy alloys (HEAs) exhibit outstanding radiation resistance in face of existing diluted alloy counterparts due to suppressed damage formation and evolution. An extension of the HEA concept is presented in this paper towards the synthesis and characterization of novel high-entropy ceramics as emergent materials for application in environments where energetic particle irradiation is a major concern. A novel carbide within the quinary refractory system CrNbTaTiW has been synthesized using magnetron-sputtering. The material exhibited nanocrystalline grains, singlephase crystal structure and C content around 50 at.%. Heavy-ion irradiation with in-situ Transmission Electron Microscopy was used to assess the irradiation response of the new highentropy carbide (HEC) at 573 K and a comparison with the HEA within the system is made. No displacement damage effects appear within the microstructures of both HEA and HEC up to a dose of 17 displacements-per-atom. Surprisingly, the HEC has not amorphized under the investigated conditions. Xe was implanted in both materials and bubbles nucleated, but smaller sizes compared with conventional nuclear materials shedding light they are potential candidates for use in nuclear energy. © 2023, The Authors. All rights reserved.

关键词： Entropy

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Observation of a 1/3 Magnetisation Plateau Phase as Evidence for the Kitaev Interaction in a Honeycomb-Lattice Antiferromagnet

arXiv

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arXiv 2023年

作者： Shangguan, Yanyan Bao, Song Dong, Zhao-Yang Xi, Ning Gao, Yi-Peng Ma, Zhen Wang, Wei Qi, Zhongyuan Zhang, Shuai Huang, Zhentao Liao, Junbo Zhao, Xiaoxue Zhang, Bo Cheng, Shufan Xu, Hao Yu, Dehong Mole, Richard A. Murai, Naoki Ohira-Kawamura, Seiko He, Lunhua Hao, Jiazheng Yan, Qing-Bo Song, Fengqi Li, Wei Yu, Shun-Li Li, Jian-Xin Wen, Jinsheng National Laboratory of Solid State Microstructures Department of Physics Nanjing University Nanjing210093 China Department of Applied Physics Nanjing University of Science and Technology Nanjing210094 China CAS Key Laboratory of Theoretical Physics Institute of Theoretical Physics Chinese Academy of Sciences Beijing100190 China Institute of Applied Physics Hubei Normal University Huangshi435002 China School of Science Nanjing University of Posts and Telecommunications Nanjing210023 China Center of Materials Science and Optoelectronics Engineering College of Materials Science and Optoelectronic Technology University of Chinese Academy of Sciences Beijing100049 China Australian Nuclear Science and Technology Organisation Lucas HeightsNSW2234 Australia Ibaraki Tokai319-1195 Japan Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing100190 China Spallation Neutron Source Science Center Dongguan523803 China Institute of High Energy Physics Chinese Academy of Sciences Beijing100049 China Collaborative Innovation center of Advanced Microstructures Nanjing University Nanjing210093 China

Fractional magnetisation plateaus, in which the magnetisation is pinned at a fraction of its saturated value within a range of external magnetic field, are spectacular macroscopic manifestations of the collective quantum behaviours. One prominent example of the plateau phase is found in spin-1/2 triangular-lattice antiferromagnets featuring strong geometrical frustration, and is often interpreted as quantum-fluctuation-stabilised state in magnetic field via the "order-by-disorder" mechanism. Here, we observe an unprecedented 1/3 magnetisation plateau between 5.2 and 7.4 T at 2 K in a spin-1 antiferromagnet Na3Ni2BiO6 with a honeycomb lattice, where conventionally no geometrical frustration is anticipated. By carrying out elastic neutron scattering measurements, we propose the spin structure of the plateau phase to be an unusual partial spin-flop ferrimagnetic order, transitioning from the zigzag antiferromagnetic order in zero field. Our theoretical calculations show that the plateau phase is stabilised by the bond-anisotropic Kitaev interaction. These results provide a new paradigm for the exploration of rich quantum phases in frustrated magnets and exotic Kitaev physics in high-spin systems. Copyright © 2023, The Authors. All rights reserved.

关键词： Bismuth compounds

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Nontrivial coupling of light into a defect:the interplay of nonlinearity and topology

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Light(science & Applications) 2020年第1期9卷 646-655页

作者： Shiqi Xia Dario Jukic Nan Wang Daria Smirnova Lev Smirnov Liqin Tang Daohong Song Alexander Szameit Daniel Leykam Jingjun Xu Zhigang Chen Hrvoje Buljan The MOE Key Laboratory of Weak-Light Nonlinear Photonics TEDA Applied Physics Institute and School of PhysicsNankai UniversityTianjin 300457China Faculty of Civil Engineering University of ZagrebA.Kacica Miosica 2610000 ZagrebCroatia Nonlinear Physics Centre Research School of PhysicsAustralian National UniversityCanberraACT 2601Australia Institute of Applied Physics Russian Academy of ScienceNizhny Novgorod 603950Russia Collaborative Innovation Center of Extreme Optics Shanxi UniversityTaiyuan 030006 ShanxiPR China Institut für Physik Universitat RostockAlbert-Einstein-Strasse 2318059 RostockGermany Center for Theoretical Physics of Complex Systems Institute for Basic Science(IBS)Daejeon 34126Republic of Korea Basic Science Program Korea University of Science and TechnologyDaejeon 34113Republic of Korea Department of Physics and Astronomy San Francisco State UniversitySan FranciscoCA 94132USA Department of Physics Faculty of ScienceUniversity of ZagrebBijenička c.3210000 ZagrebCroatia

The flourishing of topological photonics in the last decade was achieved mainly due to developments in linear topological photonic ***,when nonlinearity is introduced,many intriguing questions *** example,are there universal fingerprints of the underlying topology when modes are coupled by nonlinearity,and what can happen to topological invariants during nonlinear propagation?To explore these questions,we experimentally demonstrate nonlinearity-induced coupling of light into topologically protected edge states using a photonic platform and develop a general theoretical framework for interpreting the mode-coupling dynamics in nonlinear topological *** on laser-written photonic Su-Schrieffer-Heeger lattices,our experiments show the nonlinear coupling of light into a nontrivial edge or interface defect channel that is otherwise not permissible due to topological *** theory explains all the observations ***,we introduce the concepts of inherited and emergent nonlinear topological phenomena as well as a protocol capable of revealing the interplay of nonlinearity and *** concepts are applicable to other nonlinear topological systems,both in higher dimensions and beyond our photonic platform.

关键词： nonlinearity topological coupling

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Direct measurement of B8+p and Be7+2p cross sections for C9+Pb208 at 303 MeV

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Physical Review C 2025年第6期111卷 064602-064602页

作者： G. Yang K. Wang H. Liu W. D. Chen Y. Y. Yang F. F. Duan Jin Lei D. Y. Pang Z. H. Gao S. Y. Jin J. S. Wang X. Liu S. W. Xu J. B. Ma P. Ma Z. Bai Q. Hu Z. Y. Sun CAS Key Laboratory of High Precision Nuclear Spectroscopy Institute of Modern Physics Chinese Academy of Sciences Lanzhou 730000 China School of Nuclear Science and Technology University of Chinese Academy of Sciences Beijing 100080 China School of Physics Science and Engineering Tongji University Shanghai 200092 China Institute of Applied Physics and Computational Mathematics Beijing 100094 China School of Physics and Beijing Key Laboratory of Advanced Nuclear Materials and Physics Beihang University Beijing 100191 China School of Science Huzhou University Huzhou 313000 China Key Laboratory of Radiation Physics and Technology of the Ministry of Education Institute of Nuclear Science and Technology Sichuan University Chengdu 610064 China

Elastic scattering and breakup B8+p and Be7+2p angular distributions for C9+Pb208 at an incident energy of 303 MeV, around five times the Coulomb barrier, are reported. The data have been analyzed using the optical model and the three-body continuum discretized coupled channels formalism, assuming B8+p and Be7+2p configurations. The elastic scattering angular distributions, both measured and calculated, exhibit a relatively minor suppression of the Coulomb rainbow. Calculations combining the elastic and nonelastic breakup contributions reproduce the breakup angular distributions rather well, apart from a slight overestimation observed for Be7 fragments at forward angles. Analyses of the breakup reactions reveal that the cross section for two-proton-removal from C9 is approximately twice as large as that for one-proton-removal, despite the close proximity of the one- and two-proton separation energies.

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Tailoring the mechanical properties in Mg-11Gd-xY-0.5Zr (x = 1.5, 2.5 and 3.5 wt%) alloys: The synergistic impact of yttrium, extrusion, and aging on precipitation kinetics and phase-transformations

引用

Journal of Alloys and Compounds 2025年 1036卷

作者： Jinjun Wang Muhammad Abubaker Khan Han Wang Zhexuan Huang Adil Mansoor Mohamed A. Afifi Jingyuan Li Beijing Advanced Innovation Center for Materials Genome Engineering National Key Laboratory of Advanced Stainless Steel School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China College of Physics and Optoelectronic Engineering Shenzhen University Shenzhen 518060 China Mechanical Engineering Program School of Engineering and Applied Sciences Nile University Giza 12677 Egypt Smart Engineering Systems Research Centre Nile University Giza 12677 Egypt

Magnesium-rare earth (Mg-RE) alloys offer exceptional specific strength, presenting significant opportunities for lightweight structural applications, yet require deep understanding for process optimization. This study systematically investigates how varying Yttrium (Y) content (x = 1.5, 2.5, 3.5 wt%) interacts with thermomechanical processing (hot-extrusion followed by 200°C aging) to govern microstructural evolution and mechanical properties (at room temperature (RT) and 250°C) in Mg-11Gd-xY-0.5Zr alloys. Comprehensive characterization using scanning electron microscope (SEM), electron backscatter diffraction (EBSD), X-ray diffraction (XRD), and transmission electron microscope (TEM) revealed complex microstructural responses: increasing Y promoted grain refinement but yielded non-monotonic dynamic recrystallization (DRX) behaviour during extrusion and induced significant detrimental coarsening of the β phase morphology at higher concentrations (3.5 wt%). Aging precipitated the crucial nano-scale β′ strengthening phase, while further dynamic precipitation of β′ was observed during high-temperature (HT) deformation. Effective precipitation strengthening in the AGY 1.5 alloy (1.5 wt% Y) yielded optimal RT properties, including an ultimate tensile strength (UTS) exceeding 500 MPa. Conversely, 3.5 wt% Y led to inferior strength despite finer grains and higher indicated dislocation density, unequivocally demonstrating the adverse impact of coarse β precipitates. Enhanced ductility and extended work hardening characterized the 250°C behavior across compositions, linked to dynamic precipitation effects and thermally activated non-basal slip systems. Crucially, this work demonstrates that precipitate characteristics—specifically morphology and spatial distribution—act as the dominant factor controlling mechanical performance variations with Y content in this system, overriding contributions from grain size, texture, and dislocation density. These findings provide essentia

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Empowering Precision Medicine: AI-Driven Schizophrenia Diagnosis via EEG Signals: A Comprehensive Review from 2002-2023

arXiv

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arXiv 2023年

作者： Jafari, Mahboobeh Sadeghi, Delaram Shoeibi, Afshin Alinejad-Rokny, Hamid Beheshti, Amin García, David López Chen, Zhaolin Acharya, U. Rajendra Gorriz, Juan M. Internship in BioMedical Machine Learning Lab The Graduate School of Biomedical Engineering UNSW Sydney SydneyNSW2052 Australia Data Science and Computational Intelligence Institute University of Granada Spain BioMedical Machine Learning Lab The Graduate School of Biomedical Engineering UNSW Sydney SydneyNSW2052 Australia UNSW Data Science Hub The University of New South Wales SydneyNSW2052 Australia Health Data Analytics Program Centre for Applied Artificial Intelligence Macquarie University Sydney2109 Australia Data Science Lab School of Computing Macquarie University SydneyNSW2109 Australia Monash University Melbourne Australia School of Mathematics Physics and Computing University of Southern Queensland Springfield Australia Department of Psychiatry University of Cambridge United Kingdom

Schizophrenia (SZ) is a prevalent mental disorder characterized by cognitive, emotional, and behavioral changes. Symptoms of SZ include hallucinations, illusions, delusions, lack of motivation, and difficulties in concentration. While the exact causes of SZ remain unproven, factors such as brain injuries, stress, and psychotropic drugs have been implicated in its development. SZ can be classified into different types, including paranoid, disorganized, catatonic, undifferentiated, and residual. Diagnosing SZ involves employing various tools, including clinical interviews, physical examinations, psychological evaluations, the Diagnostic and Statistical Manual of Mental Disorders (DSM), and neuroimaging techniques. Electroencephalography (EEG) recording is a significant functional neuroimaging modality that provides valuable insights into brain function during SZ. However, EEG signal analysis poses challenges for neurologists and scientists due to the presence of artifacts, long-term recordings, and the utilization of multiple channels. To address these challenges, researchers have introduced artificial intelligence (AI) techniques, encompassing conventional machine learning (ML) and deep learning (DL) methods, to aid in SZ diagnosis. This study reviews papers focused on SZ diagnosis utilizing EEG signals and AI methods. The introduction section provides a comprehensive explanation of SZ diagnosis methods and intervention techniques. Subsequently, review papers in this field are discussed, followed by an introduction to the AI methods employed for SZ diagnosis and a summary of relevant papers presented in tabular form. Additionally, this study reports on the most significant challenges encountered in SZ diagnosis, as identified through a review of papers in this field. Future directions to overcome these challenges are also addressed. The discussion section examines the specific details of each paper, culminating in the presentation of conclusions and findings. © 2023,

关键词： Electroencephalography

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Correlations between panoramic imagery and gamma-ray background in an urban area

arXiv

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arXiv 2021年

作者： Bandstra, Mark S. Quiter, B.J. Salathe, M. Bilton, K.J. Curtis, J.C. Goldenberg, S. Joshi, T.H.Y. The Applied Nuclear Physics Program Lawrence Berkeley National Laboratory BerkeleyCA94720 United States The Department of Nuclear Engineering University of California BerkeleyCA94720 United States The Computer Science Department The College of William and Mary WilliamsburgVA23185 United States

When searching for radiological sources in an urban area, a vehicle-borne detector system will often measure complex, varying backgrounds primarily from natural gamma-ray sources. Much work has been focused on developing spectral algorithms that retain sensitivity and minimize the false positive rate even in the presence of such spectral and temporal variability. However, information about the environment surrounding the detector system might also provide useful clues about the expected background, which if incorporated into an algorithm, could improve performance. Recent work has focused on extensive measuring and modeling of urban areas with the goal of understanding how these complex backgrounds arise. This work presents an analysis of panoramic video images and gamma-ray background data collected in Oakland, California by the Radiological Multi-sensor Analysis Platform (RadMAP) vehicle. Features were extracted from the panoramic images by semantically labeling the images and then convolving the labeled regions with the detector response. A linear model was used to relate the image-derived features to gamma-ray spectral features obtained using Non-negative Matrix Factorization (NMF) under different regularizations. We find some gamma-ray background features correlate strongly with image-derived features that measure the response-adjusted solid angle subtended by sky and buildings, and we discuss the implications for the development of future, contextually-aware detection algorithms. Copyright © 2021, The Authors. All rights reserved.

关键词： Gamma rays

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Incipient nematicity from electron flat bands in a kagomé metal

arXiv

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arXiv 2024年

作者： Drucker, Nathan C. Nguyen, Thanh Mandal, Manasi Siriviboon, Phum Quan, Yujie Boonkird, Artittaya Okabe, Ryotaro Li, Fankang Burrage, Kaleb Funuma, Fumiaki Matsuda, Masaaki Abernathy, Douglas L. Williams, Travis J. Chi, Songxue Ye, Feng Nelson, Christie S. Liao, Bolin Volkov, Pavel Li, Mingda Quantum Measurement Group MIT CambridgeMA02139 United States John A. Paulson School of Engineering and Applied Sciences Harvard University CambridgeMA02138 United States Department of Nuclear Science and Engineering MIT CambridgeMA02139 United States Department of Physics MIT CambridgeMA02139 United States Department of Mechanical Engineering University of California Santa Barbara Santa BarbaraCA93106 United States Department of Chemistry MIT CambridgeMA02139 United States Neutron Scattering Division Oak Ridge National Laboratory Oak RidgeTN37830 United States X-ray Scattering Division NSLS-II Brookhaven National Laboratory UptonNY11973 United States Deparment of Physics Harvard University CambridgeMA02138 United States Deparment of Physics University of Connecticut StorrsCT06269 United States

engineering new quantum phases often requires fine tuning of the electronic, orbital, spin, and lattice degrees of freedom. To this end, kagomé lattice with flat bands has garnered great attention by hosting various topological and correlated phases,when the flat band is at the Fermi level. Here we discover the unconventional nematicity in kagomé metal CoSn, where flat bands are fully occupied below the Fermi level. Thermodynamic, dilatometry, resonant X-ray scattering, inelastic neutron scattering, Larmor diffraction, and thermoelectric measurements consistently hint at rotational symmetry-breaking and nematic order that is pronounced only near T∗ = 225 K. The observations, principally the nematic's finite temperature stability-incipience- can be explained by a phenomenological model which reveals that thermally excited flat bands promote symmetry breaking at a characteristic temperature. Our work shows that thermal fluctuations, which are typically detrimental for correlated electronic phases, can induce new ordered states of matter, avoiding the requirements for fine tuning of electronic bands. Copyright © 2024, The Authors. All rights reserved.

关键词： Fermi level

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Phase Stability of Hexagonal/cubic Boron Nitride Nanocomposites

arXiv

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arXiv 2023年

作者： Biswas, Abhijit Xu, Rui Christiansen-Salameh, Joyce Jeong, Eugene Alvarez, Gustavo A. Li, Chenxi Puthirath, Anand B. Gao, Bin Garg, Arushi Gray, Tia Kannan, Harikishan Zhang, Xiang Elkins, Jacob Pieshkov, Tymofii S. Vajtai, Robert Glen Birdwell, A. Neupane, Mahesh R. Pate, Bradford B. Ivanov, Tony Garratt, Elias J. Dai, Pengcheng Zhu, Hanyu Tian, Zhiting Ajayan, Pulickel M. Department of Materials Science and Nanoengineering Rice University HoustonTX77005 United States Sibley School of Mechanical and Aerospace Engineering Cornell University IthacaNY14853 United States Department of Physics and Astronomy Rice University HoustonTX77005 United States Department of Materials Science and Engineering Indian Institute of Technology Kanpur Kanpur208016 India Applied Physics Graduate Program Smalley-Curl Institute Rice University HoustonTX77005 United States DEVCOM Army Research Laboratory RF Devices and Circuits AdelphiMD20783 United States Naval Research Laboratory WashingtonDC20375 United States

Boron nitride (BN) is an exceptional material and among its polymorphs, two-dimensional (2D) hexagonal and three-dimensional (3D) cubic BN (h-BN and c-BN) phases are most common. The phase stability regimes of these BN phases are still under debate and phase transformations of h-BN/c-BN remain a topic of interest. Here, we investigate the phase stability of 2D/3D h-BN/c-BN nanocomposites and show that the co-existence of two phases can lead to strong non-linear optical properties and low thermal conductivity at room temperature. Furthermore, spark-plasma sintering of the nanocomposite shows complete phase transformation to 2D h-BN with improved crystalline quality, where 3D c-BN grain sizes governs the nucleation and growth kinetics. Our demonstration might be insightful in phase engineering of BN polymorphs based nanocomposites with desirable properties for optoelectronics and thermal energy management applications. © 2023, CC BY.

关键词： Nanocomposites

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