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arXiv 2023年

作者： Rogers, Ariel Niyonshuti, Isabelle I. Ou, Jun Shrestha, Diksha Chen, Jingyi Wang, Yong Department of Physics University of Arkansas FayettevilleAR72701 United States Department of Chemistry and Biochemistry University of Arkansas FayettevilleAR72701 United States School of Engineering California State Polytechnic University Humboldt ArcataCA95521 United States Mechanical Engineering Program California State Polytechnic University Humboldt ArcataCA95521 United States Cell and Molecular Graduate Program University of Arkansas FayettevilleAR72701 United States Materials Science and Engineering Program University of Arkansas FayettevilleAR72701 United States

Light-based nanowelding of metallic nanoparticles is of particular interest because it provides convenient and controlled means for the conversion of nanoparticles into microstructures and fabrication of nanodevices. Here, we demonstrated the wavelength dependence of laser-induced nanowelded shapes of silver nanoparticles (AgNPs). We observed that the nanowelded microstructures illuminated by the 405 nm laser only were more branched than those formed with illumination of both the 405 nm and 532 nm lasers. We quantified this observation by several compactness descriptors and examined the dependence of the power of the 532 nm laser. More importantly, to understand the experimental observations, we formulated and tested a hypothesis by calculating the wavelength-dependent electric field enhancement due to surface plasmon resonance of the AgNPs and nanowelded microstructures when illuminated with lights at the two wavelengths. Based on the different patterns of "hot spots" for welding AgNPs from these calculations, numerical simulations successfully "reproduced" the different shapes of nanowelded microstructures, supporting our hypothesis. This work suggests the possibility of light-based controlling the shapes of laser-induced nanowelded microstructures of metallic nanoparticles. This work is expected to facilitate the development of better nanowelding strategies of metallic nanoparticles for broader applications. Copyright © 2023, The Authors. All rights reserved.

关键词： Surface plasmon resonance

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Electronic and Optical Excitations in van der Waals Materials from a Non-Empirical Wannier-Localized Optimally-Tuned Screened Range-Separated Hybrid Functional

arXiv

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arXiv 2024年

作者： Camarasa-Gómez, María Gant, Stephen E. Ohad, Guy Neaton, Jeffrey B. Ramasubramaniam, Ashwin Kronik, Leeor Department of Molecular Chemistry and Materials Science Weizmann Institute of Science Rehovoth7610001 Israel Department of Physics University of California BerkeleyCA94720 United States Materials Sciences Division Lawrence Berkeley National Laboratory BerkeleyCA94720 United States Kavli Energy NanoSciences Institute at Berkeley University of California BerkeleyCA94720 United States Department of Mechanical and Industrial Engineering University of Massachusetts Amherst AmherstMA01003 United States Materials Science and Engineering Graduate Program University of Massachusetts AmherstMA01003 United States

Accurate prediction of electronic and optical excitations in van der Waals (vdW) materials is a long-standing challenge for density functional theory. The recently proposed Wannier-localized optimally-tuned screened range-separated hybrid (WOT-SRSH) functional has proven successful in non-empirical determination of electronic band gaps and optical absorption spectra for various covalent and ionic crystals. However, for vdW materials the tuning of the material- and structure-dependent functional parameters has, until now, only been attained semi-empirically. Here, we present a non-empirical WOT-SRSH approach applicable to vdW materials, with the optimal functional parameters transferable between monolayer and bulk. We apply this methodology to prototypical vdW materials: black phosphrous, moldybdenum disulfide, and hexagonal boron nitride (in the latter case including zero-point renormalization). We show that the WOT-SRSH approach consistently achieves accuracy levels comparable to experiments and ab initio many-body perturbation theory (MBPT) calculations for band structures and optical absorption spectra, both on its own and as an optimal starting point for MBPT calculations. Copyright © 2024, The Authors. All rights reserved.

关键词： Energy gap

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Maxwell’s Demon walks into Wall Street: Stochastic Thermodynamics meets Expected Utility Theory

arXiv

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arXiv 2023年

作者： Ducuara, Andrés F. Skrzypczyk, Paul Buscemi, Francesco Sidajaya, Peter Scarani, Valerio Yukawa Institute for Theoretical Physics Kyoto University Kitashirakawa Oiwakecho Sakyo-ku Kyoto606-8502 Japan Center for Gravitational Physics and Quantum Information Yukawa Institute for Theoretical Physics Kyoto University Japan H.H. Wills Physics Laboratory University of Bristol Tyndall Avenue BristolBS8 1TL United Kingdom CIFAR Azrieli Global Scholars program CIFAR Toronto Canada Graduate School of Informatics Nagoya University Chikusa-Ku Nagoya464-8601 Japan Centre for Quantum Technologies National University of Singapore 3 Science Drive 2 Singapore117543 Singapore Department of Physics National University of Singapore 2 Science Drive 3 Singapore117542 Singapore

The interplay between thermodynamics and information theory has a long history, but its quantitative manifestations are still being explored. We import tools from expected utility theory from economics into stochastic thermodynamics. We prove that, in a process obeying Crooks’ fluctuation relations, every α Rényi divergence between the forward process and its reverse has the operational meaning of the "certainty equivalent" of dissipated work (or, more generally, of entropy production) for a player with risk aversion r = α−1. The two known cases α = 1 and α = ∞ are recovered and receive the new interpretation of being associated to a risk-neutral and an extreme risk-averse player respectively. Among the new results, the condition for α = 0 describes the behavior of a risk-seeking player willing to bet on the transient violations of the second law. Our approach further leads to a generalized Jarzynski equality, and generalizes to a broader class of statistical divergences. Copyright © 2023, The Authors. All rights reserved.

关键词： Information theory

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Elementary excitations of single-photon emitters in hexagonal Boron Nitride

arXiv

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arXiv 2024年

作者： Pelliciari, Jonathan Mejia, Enrique Woods, John M. Gu, Yanhong Li, Jiemin Chand, Saroj B. Fan, Shiyu Watanabe, Kenji Taniguchi, Takashi Bisogni, Valentina Grosso, Gabriele National Synchrotron Light Source II Brookhaven National Laboratory UptonNY11973 United States Photonics Initiative Advanced Science Research Center City University of New York New York CityNY10031 United States Research Center for Functional Materials National Institute for Materials Science Ibaraki Tsukuba305-0044 Japan International Center for Materials Nanoarchitectonics National Institute for Materials Science Ibaraki Tsukuba305-0044 Japan Physics Program Graduate Center City University of New York New YorkNY10016 United States

Single-photon emitters serve as building blocks for many emerging concepts in quantum photonics. The recent identification of bright, tunable, and stable emitters in hexagonal boron nitride (hBN) has opened the door to quantum platforms operating across the infrared to ultraviolet spectrum. While it is widely acknowledged that defects are responsible for single-photon emitters in hBN, crucial details regarding their origin, electronic levels, and orbital involvement remain unknown. Here, we employ a combination of resonant inelastic X-ray scattering and photoluminescence spectroscopy in defective hBN unveiling an elementary excitation at 285 meV that gives rise to a plethora of harmonics correlated with single-photon emitters. We discuss the importance of N π∗ anti-bonding orbitals in shaping the electronic states of the emitters. The discovery of the elementary excitations of hBN provides new fundamental insights into quantum emission in low-dimensional materials, paving the way for future investigations in other platforms. Copyright © 2024, The Authors. All rights reserved.

关键词： Defects

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Strong nonreciprocal acoustic extinction and asymmetric audibility from spinning fluid scatterers

引用

Physical Review B 2023年第16期108卷 165129-165129页

作者： Yao-Ting Wang Heedong Goh Sander A. Mann Andrea Alù Photonics Initiative Advanced Science Research Center City University of New York New York New York 10031 USA Department of Photonics National Sun Yat-Sen University Kaohsiung 804201 Taiwan Department of Electrical and Computer Engineering The University of Texas at Austin Austin Texas 78712 USA Physics Program Graduate Center City University of New York New York New York 10026 USA

Lorentz reciprocity places important constraints on the response of systems to wave excitations, and surpassing these constraints is of both fundamental and applied interest. In the context of scattering, reciprocity requires that the total extinction of an object is identical when excited from opposite directions, regardless of the asymmetry of the scatterer. Here, we demonstrate that, by combining multiple scatterers that break time-reversal symmetry, this extinction symmetry can be largely violated. We consider spinning cylinders, demonstrating that nonreciprocity must be paired with broken parity symmetry to enable large extinction contrast. As a dramatic example, we show a system that strongly scatters when excited from one side, but it is cloaked for the opposite excitation. Our results pave the way for approaches to asymmetric audibility and scattering manipulation, and they may readily translate to other wave domains.

关键词： Acoustic metamaterials Acoustics Non-reciprocal propagation

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physics based learning effectiveness PhET simulation model using Problem Based Learning (PBL) for self-independent learning on material and energy enterprises learners MAN 3 Sleman 6

Physics based learning effectiveness PhET simulation model u...

引用

6th International Conference on Mathematics, science, and Education, ICMSE 2019

作者： Saputra, S. Jumadi Wilujeng, I. Physics Education Post Graduate Program State University of Yogyakarta Jl. Colombo No 1 Yogyakarta Indonesia Physics Education Department Faculty of Math and Science Yogyakarta State University Jl. Colombo No.1 Yogyakarta Indonesia

This study aims to determine the effectiveness of the use of Phet simulation applications on smartphones Problem Based Learning (PBL) learning models of students' learning independence and the different effects of learning independence. The type of research applied was quasi experiment. Research design used Non-equivalent Control Group Design. The population in this study was all students of class X of MAN 3 Sleman which was divided into 8 classes. The sampling technique used cluster purposive sampling. Both classes are given treatment with the Problem Based Learning model assisted by the Phet application which was installed on each student's smartphone. The average level of learning independence of students in the modelling class after they participated in learning activities included in the good category, and in the implementation, class included in the good category. The significance level shows the numbers in the effective category. So it can be stated that the learning independence questionnaire of both classes was effective, it can be concluded that the Problem Based Learning model assisted by the Phets application is effective in terms of the achievement of the learning independence of students in class X of MAN 3 Sleman in the academic year 2017/2018. © Published under licence by IOP Publishing Ltd.

关键词： Students

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Full-Duplex Beamforming in the Sub-Terahertz Regime

Full-Duplex Beamforming in the Sub-Terahertz Regime

引用

International Conference on Infrared and Millimeter Waves

作者： Subhajit Karmakar Atsutse Kludze Jacques Doumani Andrey Baydin Junichiro Kono Yasaman Ghasempour Department of Electrical and Computer Engineering Princeton University Princeton NJ USA Department of Electrical and Computer Engineering Rice University Houston TX USA Applied Physics Graduate Program Smalley-Curl Institute Rice University Houston TX USA Smalley-Curl Institute Rice University Houston TX USA Department of Physics and Astronomy Rice University Houston TX USA Department of Material Science and NanoEngineering Rice University Houston TX USA

We propose a novel architecture that realizes full-duplex directional beamforming in the sub-terahertz regime. Our architecture leverages the frequency-controlled beam steering of leaky-wave antenna together with the polarization-dependent response of aligned single-wall carbon nanotubes. We evaluate the performance of this architecture via preliminary experiments.

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Conic sections in ferroelectric nematics: Experiments and mathematical modeling

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Physical Review Research 2024年第4期6卷 043207-043207页

作者： Priyanka Kumari Olexandr Kurochkin Vassili G. Nazarenko Oleg D. Lavrentovich Dmitry Golovaty Peter Sternberg Advanced Materials and Liquid Crystal Institute Kent State University Kent Ohio 44242 USA Materials Science Graduate Program Kent State University Kent Ohio 44242 USA Institute of Physics National Academy of Sciences of Ukraine Prospect Nauky 46 Kyiv 03028 Ukraine Institute of Physical Chemistry Polish Academy of Sciences Kasprzaka 44/52 01-224 Warsaw Poland Department of Physics Kent State University Kent Ohio 44242 USA Department of Mathematics The University of Akron Akron Ohio 44325 USA Department of Mathematics Indiana University Bloomington Indiana 47405 USA

The domain structure of a fluid ferroelectric nematic is dramatically different from the domain structure of solid ferroelectrics since it is not restricted by rectilinear crystallographic axes and planar surface facets. We demonstrate that thin films of a ferroelectric nematic seeded by colloidal inclusions produce domain walls (DWs) in the shape of conics such as a parabola. These conics reduce the bound charge within the domains and at the DWs. An adequate description of the domain structures requires one to analyze the electrostatic energy, which is a challenging task. Instead, we demonstrate that a good approximation to the experimentally observed polydomain textures is obtained when the divergence of spontaneous polarization—which causes the bound charge—is heavily penalized by assuming that the elastic constant of splay in the Oseen-Frank energy is much larger than those for twist and bend. The model takes advantage of the fact that the polarization vector is essentially parallel to the nematic director throughout the sample.

关键词： Defects Domains Ferroelectricity Ferroelectric liquid crystals Ferroelectrics Liquid crystals

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Joint Observation of the Galactic Center with MAGIC and CTA-LST-1 38

Joint Observation of the Galactic Center with MAGIC and CTA-...

引用

38th International Cosmic Ray Conference, ICRC 2023

作者： Abe, Shotaro Berti, Alessio Di Pierro, Federico López-Coto, Rubén Moralejo, Abelardo Ohtani, Yoshiki Sitarek, Julian Strzys, Marcel Suda, Yusuke Vovk, Ievgen Abe, H. Abe, K. Abe, S. Abhir, J. Acciari, V.A. Aguasca-Cabot, A. Agudo, I. Alvarez Crespo, N. Aniello, T. Ansoldi, S. Antonelli, L.A. Aramo, C. Arbet-Engels, A. Cornelia, A. Artero, M. Asano, K. Aubert, P. Baack, D. Babić, A. Baktash, A. Bamba, A. Baquero Larriva, A. Baroncelli, L. Barres de Almeida, U. Barrio, J.A. Batkovic, I. Baxter, J. Becerra González, J. Bednarek, W. Bernardini, E. Bernardos, M.I. Bernete Medrano, J. Berti, A. Besenrieder, J. Bhattacharjee, P. Biederbeck, N. Bigongiari, C. Biland, A. Bissaldi, E. Blanch, O. Bonnoli, G. Bordas, P. Bošnjak, Ž. Bulgarelli, A. Burelli, I. Burmistrov, L. Buscemi, M. Busetto, G. Campoy-Ordaz, A. Cardillo, M. Caroff, S. Carosi, A. Carosi, R. Carrasco, M.S. Carretero-Castrillo, M. Cassol, F. Castro-Tirado, A.J. Cauz, D. Cerasole, D. Ceribella, G. Chai, Y. Cheng, K. Chiavassa, A. Chikawa, M. Chilingarian, A. Chytka, L. Cifuentes, A. Cikota, S. Colombo, E. Contreras, J.L. Cortina, J. Costantini, H. Covino, S. D’Amico, G. Dalchenko, M. D’Elia, V. Da Vela, P. Dazzi, F. De Angelis, A. de Bony de Lavergne, M. De Lotto, B. De Lucia, M. de Menezes, R. Del Peral, L. Deleglise, G. Delfino, M. Delgado, C. Delgado Mengual, J. della Volpe, D. Dellaiera, M. Del Popolo, A. Depaoli, D. Di Piano, A. Di Pierro, F. Di Pilato, A. Di Tria, R. Di Venere, L. Díaz, C. Dominik, R.M. Dominis Prester, D. Donini, A. Dorner, D. Doro, M. Eisenberger, L. Elsässer, D. Emery, G. Escudero, J. Fallah Ramazani, V. Fariña, L. Fattorini, A. Ferrara, G. Ferrarotto, F. Fiasson, A. Foffano, L. Font, L. Freixas Coromina, L. Fröse, S. Fukami, S. Fukazawa, Y. Garcia, E. Garcia López, R. Garczarczyk, M. Gasbarra, C. Gasparrini, D. Gasparyan, S. Gaug, M. Geyer, D. Giesbrecht Paiva, J. Giglietto, N. Giordano, F. Gliwny, P. Godinovic, N. Grau, R. Green, J. Green, D. Gunji, S. Günther, P. Hackfeld, J. Hadasch, D. Hahn, A. Institute for Cosmic Ray Research Kashiwa-no-ha 5-1-5 Kashiwa-shi Chiba Japan Max-Planck-Institut für Physik Föhringer Ring 6 München80805 Germany INFN Sezione di Torino Via P. Giuria 1 Torino10125 Italy Instituto de Astrofísica de Andalucía-CSIC Glorieta de la Astronomía s/n Granada18008 Spain The Barcelona Institute of Science and Technology Campus UAB Bellaterra Barcelona08193 Spain Faculty of Physics and Applied Informatics University of Lodz ul. Pomorska 149-153 Lodz90-236 Poland Physics Program Graduate School of Advanced Science and Engineering Hiroshima University Hiroshima739-8526 Japan Institute for Cosmic Ray Research University of Tokyo Japan Department of Physics Tokai University Japan ETH Zürich Switzerland Instituto de Astrofísica de Canarias Departamento de Astrofísica Universidad de La Laguna Spain Departament de Física Quàntica i Astrofísica Institut de Ciències del Cosmos Universitat de Barcelona IEEC-UB Spain EMFTEL department IPARCOS Universidad Complutense de Madrid Spain Italy INFN Sezione di Trieste Università degli Studi di Udine Italy Italy INAF Osservatorio Astronomico di Roma Italy INFN Sezione di Napoli Italy INFN Sezione di Padova Università degli Studi di Padova Italy LAPP Univ. Grenoble Alpes Univ. Savoie Mont Blanc CNRS-IN2P3 Annecy France Department of Physics TU Dortmund University Germany Croatia Universität Hamburg Institut für Experimentalphysik Germany Graduate School of Science University of Tokyo Japan Universidad del Azuay Ecuador INAF Osservatorio di Astrofisica e Scienza dello spazio di Bologna Italy Centro Brasileiro de Pesquisas Físicas Brazil CIEMAT Spain INFN Sezione di Bari Politecnico di Bari Italy INAF Osservatorio Astronomico di Brera Italy University of Geneva Département de physique nucléaire et corpusculaire Switzerland INFN Sezione di Catania Italy Departament de Física CERES-IEEC Universitat Autónoma de Barcelona Spain Italy Università di Pisa INFN Pisa Italy Aix Mars

MAGIC is a system of two Imaging Atmospheric Cherenkov Telescopes (IACTs), designed to detect very-high-energy gamma rays, and is operating in stereoscopic mode since 2009 at the Observatorio del Roque de Los Muchachos in La Palma, Spain. In 2018, the prototype IACT of the Large-Sized Telescope (LST-1) for the Cherenkov Telescope Array, a next-generation ground-based gamma-ray observatory, was inaugurated at the same site, at a distance of approximately 100 meters from the MAGIC telescopes. Using joint observations between MAGIC and LST-1, we developed a dedicated analysis pipeline and established the threefold telescope system via software, achieving the highest sensitivity in the northern hemisphere. Based on this enhanced performance, MAGIC and LST-1 have been jointly and regularly observing the Galactic Center, a region of paramount importance and complexity for IACTs. In particular, the gamma-ray emission from the dynamical center of the Milky Way is under debate. Although previous measurements suggested that a supermassive black hole Sagittarius A* plays a primary role, its radiation mechanism remains unclear, mainly due to limited angular resolution and sensitivity. The enhanced sensitivity in our novel approach is thus expected to provide new insights into the question. We here present the current status of the data analysis for the Galactic Center joint MAGIC and LST-1 observations. © Copyright owned by the author(s) under the terms of the Creative Commons.

关键词： Cosmology

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Temporal refraction and reflection in modulated mechanical metabeams: theory and physical observation

arXiv

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arXiv 2025年

作者： Wang, Shaoyun Shao, Nan Chen, Hui Chen, Jiaji Qian, Honghua Wu, Qian Duan, Huiling Alù, Andrea Huang, Guoliang Department of Mechanical and Aerospace Engineering University of Missouri ColumbiaMO65211 United States Center for Mechanics Plus Under Extreme Environments School of Mechanical Engineering and Mechanics Ningbo University Ningbo315211 China Photonics Initiative Advanced Science Research Center City University of New York New YorkNY United States Physics Program Graduate Center City University of New York New YorkNY United States Department of Mechanics and Engineering Science College of Engineering Peking University Beijing100871 China

Wave reflection and refraction at a time interface follow different conservation laws compared to conventional scattering at a spatial interface. This study presents the experimental demonstration of refraction and reflection of flexural waves across a temporal boundary in a continuum-based mechanical metabeam, and unveils opportunities that emerge by tailoring temporal scattering phenomena for phononic applications. We observe these phenomena in an elastic beam attached to an array of piezoelectric patches that can vary in time the effective elastic properties of the beam. Frequency conversion and phase conjugation are observed upon a single temporal interface. These results are consistent with the temporal Snell’s law and Fresnel equations for temporal interfaces. Further, we illustrate the manipulation of amplitude and frequency spectra of flexural wave temporal refraction and reflection through multi-stepped temporal interfaces. Finally, by implementing a smooth time variation of wave impedance, we numerically and experimentally demonstrate the capabilities of the temporal metabeam to realize waveform morphing and information coding. Our findings lay the foundation for developing time-mechanical metamaterials and time-phononic crystals, offering new avenues for advanced phonon manipulation in both wave amplitude and frequency. © 2025, CC BY.

关键词： Phonons

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