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Spacetime evolution of lepton number densities and wave-packet-like effects for neutrino flavor and chiral oscillations in quantum field theory

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Physical Review D 2023年第5期108卷 056009-056009页

作者： Apriadi Salim Adam Nicholas J. Benoit Yuta Kawamura Yamato Matsuo Takuya Morozumi Yusuke Shimizu Naoya Toyota Research Center for Quantum Physics National Research and Innovation Agency (BRIN) South Tangerang 15314 Indonesia Physics Program Graduate School of Advanced Science and Engineering Hiroshima University Higashi-Hiroshima 739-8526 Japan Yokkaichi city Mie Japan Akashi city Hyogo Japan Core of Research for the Energetic Universe Hiroshima University Higashi-Hiroshima 739-8526 Japan Hiroshima city Hiroshima Japan

We present a formulation of lepton family numbers, based on quantum field theory, for neutrino oscillation phenomenology that can be applied to nonrelativistic and relativistic energies for neutrinos. It is formulated for both types of neutrinos, Dirac and Majorana. The formulation is constructed as the time evolution of a lepton family number density operator. Then, the time evolution of the lepton family number density operator becomes dependent on the mass and new features appear. The expectation value of the density operator is evaluated for the initial state with a Gaussian distribution for the momentum amplitude. This enables us to study wave-packet-like decoherence effects. We show in the nonrelativistic regime, the type of neutrino mass are distinguishable even under the presence of wave-packet-like decoherence effects.

关键词： Neutrino oscillations Quantum field theory Neutrinos Mass

Photothermal responsivity of van der Waals material-based nanomechanical resonators

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arXiv 2022年

作者： Aguila, Myrron Albert C. Esmenda, Joshoua C. Wang, Jyh-Yang Lee, Teik-Hui Chen, Yen-Chun Yang, Chi-Yuan Lin, Kung-Hsuan Chang-Liao, Kuei-Shu Kafanov, Sergey Pashkin, Yuri A. Chen, Chii-Dong Department of Engineering and System Science National Tsing Hua University Hsinchu30013 Taiwan Nano Science and Technology Program Taiwan International Graduate Program National Tsing Hua University Academia Sinica Taiwan Institute of Physics Academia Sinica Nankang Taipei11529 Taiwan Department of Physics Lancaster University LancasterLA1 4YB United Kingdom

Nanomechanical resonators made from van der Waals materials (vdW NMRs) provide a new tool for sensing absorbed laser power. The photothermal response of vdW NMRs, quantified from the resonant frequency shifts induced by optical absorption, is enhanced when incorporated in a Fabry-Perot (FP) interferometer. Along with the enhancement comes the dependence of the photothermal response on NMR displacement, which lacks investigation. Here, we address the knowledge gap by studying electromotively driven niobium diselenide drumheads fabricated on highly reflective substrates. We use a FP-mediated absorptive heating model to explain the measured variations of the photothermal response. The model predicts a higher magnitude and tuning range of photothermal responses on few-layer and monolayer NbSe2 drumheads, which outperform other clamped vdW drum-type NMRs at a laser wavelength of 532 nm. Further analysis of the model shows that both the magnitude and tuning range of NbSe2 drumheads scale with thickness, establishing a displacement-based framework for building bolometers using FP-mediated vdW NMRs. © 2022, CC BY.

关键词： Van der Waals forces

Magnetically tuned continuous transition from weak to strong coupling in terahertz magnon polaritons

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Physical Review Research 2023年第1期5卷 L012039-L012039页

作者： Andrey Baydin Kenji Hayashida Takuma Makihara Fuyang Tay Xiaoxuan Ma Wei Ren Guohong Ma G. Timothy Noe, II Ikufumi Katayama Jun Takeda Hiroyuki Nojiri Shixun Cao Motoaki Bamba Junichiro Kono Department of Electrical and Computer Engineering Rice University Houston Texas 77005 USA Smalley-Curl Institute Rice University Houston Texas 77005 USA Division of Applied Physics Graduate School of Engineering Hokkaido University Sapporo Hokkaido 060-8628 Japan Department of Physics and Astronomy Rice University Houston Texas 77005 USA Applied Physics Graduate Program Smalley-Curl Institute Rice University Houston Texas 77005 USA Department of Physics International Center of Quantum and Molecular Structures and Materials Genome Institute Shanghai University 200444 Shanghai China Department of Physics Graduate School of Engineering Science Yokohama National University Yokohama 240-8501 Japan Institute for Materials Research Tohoku University Sendai 980-8577 Japan The Hakubi Center for Advanced Research Kyoto University Kyoto 606-8502 Japan Department of Physics I Kyoto University Kyoto 606-8502 Japan PRESTO Japan Science and Technology Agency Kawaguchi 332-0012 Japan Department of Materials Science and NanoEngineering Rice University Houston Texas 77005 USA

Depending on the relative rates of coupling and dissipation, a light-matter coupled system is either in the weak- or strong-coupling regime. Here, we present a unique system where the coupling rate continuously increases with an externally applied magnetic field while the dissipation rate remains constant, allowing us to monitor a weak-to-strong coupling transition as a function of magnetic field. We observed a Rabi splitting of a terahertz magnon mode in yttrium orthoferrite above a threshold magnetic field of ∼14 T. Based on a microscopic theoretical model, we show that with increasing magnetic field the magnons transition into magnon polaritons through an exceptional point, which will open up new opportunities for in situ control of non-Hermitian systems.

关键词： Antiferromagnetism High magnetic fields Magneto-optics Magnons Polaritons Non-Hermitean systems Terahertz time-domain spectroscopy Transfer matrix method

Development of a do-it-yourself (D.I.Y.) gel electrophoresis apparatus for Grade-12 STEM general biology students 2

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Development of a do-it-yourself (D.I.Y.) gel electrophoresis...

2nd International Annual Meeting on STEM Education, IAMSTEM 2019

作者： Gamale, Janne Noelle L. Acut, Dharel P. Niere, Karla Marie Frances P. Silagan, Gwen Stephany S. Curaraton, Ethel P. Latonio, Guadalupe C. Latonio, Rhett Anthony C. Magsayo, Joy R. High School Department Sotero B. Cabahug Forum for Literacy Consolacion Cebu6001 Philippines Applied Physics Program National Institute of Physics College of Science University of the Philippines - Diliman Roxas Ave. Diliman Quezon City1101 Philippines Science Education Program Graduate School College of Teacher Education Cebu Normal University Osmeña Blvd. Cebu City Cebu6000 Philippines Department of Science and Mathematics Education College of Education Mindanao State University - Iligan Institute of Technology Iligan City9200 Philippines

A hurdle to effective science education in schools is often the lack of teaching materials. Teaching science education in the 21st century requires direct visualization and manipulation with effective use and implementation for meaningful learning to occur, thus, unleashing students' potential towards the lesson, boosting their engagement in learning, and applying the knowledge into skills. This study was carried out to develop a do-it-yourself gel electrophoresis apparatus. This study was conducted in Cebu Normal University, Philippines with nineteen (19) teachers from the Methods of Teaching science and Instructional Trends and Issues Class who evaluated the apparatus in terms of usability and functionality. The respondents tested the Gel Electrophoresis apparatus by conducting the experiment and they evaluated the apparatus' functionality and usability by using an evaluation sheet which is composed of eleven (11) usability questions, four (4) functionality questions. Suggestions were also asked to improve the said apparatus. After gathering data, the suggestions made by the respondents were incorporated which resulted to the improved D.I.Y. Gel Electrophoresis Apparatus. A manual with the procedures was also designed to further guide students and teachers on how to build the apparatus. With the findings and results obtained in the study, the respondents recommended the usage of the developed do-it-yourself gel electrophoresis apparatus in their respective classes and agreed that it is a good source of learning the concept of gel electrophoresis as a 21st century biological technique. The apparatus was easy to set-up and is of low-cost. During experimentation, the apparatus yielded with a positive result - the separation of food dyes which follows the principle of gel electrophoresis. Moreover, the experiment encourages creativity and it helps with the understanding of the nature of DNA and the concept of gel electrophoresis as a 21st century biological skills. ©

关键词： Students

Ferroelectric nematic liquids with conics

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arXiv 2023年

作者： Kumari, Priyanka Basnet, Bijaya Wang, Hao Lavrentovich, Oleg D. Advanced Materials and Liquid Crystal Institute Kent State University KentOH44242 United States Materials Science Graduate Program Kent State University KentOH44242 United States Department of Physics Kent State University KentOH44242 United States

Spontaneous electric polarization of solid ferroelectrics follows aligning directions of crystallographic axes. Domains of differently oriented polarization are separated by domain walls (DWs), which are predominantly flat and run along directions dictated by the bulk translational order and the sample surfaces. Here we explore DWs in a ferroelectric nematic (NF) liquid crystal, which is a fluid with polar long-range orientational order but no crystallographic axes nor facets. We demonstrate that DWs in the absence of bulk and surface aligning axes are shaped as conic sections. The conics bisect the angle between two neighboring polarization fields to avoid electric charges. The remarkable bisecting properties of conic sections, known for millennia, play a central role as intrinsic features of liquid ferroelectrics. The findings could be helpful in designing patterns of electric polarization and space charge. © 2023, CC BY.

关键词： Ferroelectric materials

Physical and Chemical Properties of Galactic Molecular Gas toward QSO J1851+0035

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arXiv 2024年

作者： Narita, Kanako Sakamoto, Seiichi Koda, Jin Yoshimura, Yuki Kohno, Kotaro Department of Astronomy Graduate School of Science The University of Tokyo 7-3-1 Hongo Bunkyo-ku Tokyo133-0033 Japan National Astronomical Observatory of Japan National Institutes of Natural Sciences 2-21-1 Osawa Mitaka Tokyo181-8588 Japan Astronomical Science Program Graduate Institute for Advanced Studies SOKENDAI 2-21-1 Osawa Mitaka Tokyo181-8588 Japan Department of Physics and Astronomy Stony Brook University Stony BrookNY11794-3800 United States Institute of Astronomy Graduate School of Science The University of Tokyo 2-21-1 Osawa Mitaka Tokyo181-0015 Japan Research Center for the Early Universe Graduate School of Science The University of Tokyo 7-3-1 Hongo Bunkyo Tokyo113-0033 Japan

ALMA data toward QSO J1851+0035 (l=33.498◦, b=+0.194◦) were used to study absorption lines by Galactic molecular gas. We detected 17 species (CO, 13CO, C18O, HCO+, H13CO+, HCO, H2CO, C2H, c-C3H, c-C3H2, CN, HCN, HNC, CS, SO, SiO, and C) and set upper limits to 18 species as reference values for chemical models. About 20 independent velocity components at 4.7–10.9 kpc from the Galactic Center were identified. Their column density and excitation temperature estimated from the absorption study, as well as the CO intensity distributions obtained from the FUGIN survey, indicate that the components with τ 1 correspond to diffuse clouds or cloud outer edges. Simultaneous multiple-Gaussian fitting of CO J=1–0 and J=2–1 absorption lines shows that these are composed of narrow- and broad-line components. The kinetic temperature empirically expected from the high HCN/HNC isomer ratio (4) reaches 40 K and the corresponding thermal width accounts for the line widths of the narrow-line components. CN-bearing molecules and hydrocarbons have tight and linear correlations within the groups. The CO/HCO+ abundance ratio showed a dispersion as large as 3 orders of magnitude with a smaller ratio in a smaller N(HCO+) (or lower AV) range. Some of the velocity components are detected in single-dish CO emission and ALMA HCO+ absorption but without corresponding ALMA CO absorption. This may be explained by the mixture of clumpy CO emitters not resolved with the ∼1 pc single-dish beam surrounded by extended components with a very low CO/HCO+ abundance ratio (i.e., CO-poor gas). Copyright © 2024, The Authors. All rights reserved.

关键词： Molecules

Coherent Acoustic Phonons in Bi2Se3 Ultrathin Films Probed by Femtosecond, Optical Pump-Probe Spectroscopy

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Coherent Acoustic Phonons in Bi2Se3 Ultrathin Films Probed b...

CLEO: Fundamental science, CLEO:FS 2024 - Part of Conference on Lasers and Electro-Optics, CLEO 2024

作者： Cheng, Jing Niherysh, Kiryl A. Francis, Peter Chakraborty, Debamitra Lombardi, Floriana Erts, Donats Prischepa, Serghej L. Laszcz, Adam Komissarov, Ivan V. Sobolewski, Roman Materials Science Graduate Program University of Rochester RochesterNY14627 United States Laboratory for Laser Energetics University of Rochester RochesterNY14623-1299 United States Department of Microtechnology and Nanoscience Chalmers University of Technology Gothenburg Sweden Institute of Chemical Physics University of Latvia Riga Latvia Department of Electrical and Computer Engineering University of Rochester RochesterNY14627 United States Dipartimento di Fisica "E.R. Caianiello" Università degli Studi di Salerno Sa FiscianoI-84084 Italy Lukasiewicz Research Network Institute of Microelectronics and Photonics WarszawaPL-02668 Poland

ISBN: (纸本)9781957171395

The dynamics of coherent acoustic phonons in the Bi2Se3 layered crystal system are investigated. The findings reveal that the frequency evolution of breathing modes with the number of the material quintuple layers and the dispersion relation both can be explained by a modified chain model with a nonuniform coupling force. © Optica Publishing Group 2024, © 2024 The Author(s)

关键词： Ultrathin films

Thermal Metasurfaces: Selective Emission of Custom Wavefronts from a Structured Ultrathin Optical Element

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Thermal Metasurfaces: Selective Emission of Custom Wavefront...

Conference on Lasers and Electro-Optics (CLEO)

作者： Adam C. Overvig Sander A. Mann Andrea Alù Photonics Initiative Advanced Science Research Center City University of New York New York NY USA Physics Program Graduate Center of the City University of New York New York NY USA

We demonstrate a metasurface platform based on quasibound states in the continuum capable of generating partially coherent designer wavefronts via thermal emission.

ISBN: (数字)9781957171050

ISBN: (纸本)9781665466660

We demonstrate a metasurface platform based on quasibound states in the continuum capable of generating partially coherent designer wavefronts via thermal emission.

关键词： Stimulated emission Lasers and electrooptics Metasurfaces Electrooptical waveguides

Nonlinear and nonreciprocal transport effects in untwinned thin films of ferromagnetic Weyl metal SrRuO3

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arXiv 2023年

作者： Kar, Uddipta Lu, Elisha Cho-Hao Singh, Akhilesh Kr Reddy, P.V. Sreenivasa Han, Youngjoon Li, Xinwei Cheng, Cheng-Tung Yang, Song Lin, Chun-Yen Cheng, I-Chun Hsu, Chia-Hung Hsieh, David Lee, Wei-Cheng Guo, Guang-Yu Lee, Wei-Li Institute of Physics Academia Sinica Nankang Taipei11529 Taiwan Department of Physics National Taiwan University Taipei10617 Taiwan Department of Physics Applied Physics and Astronomy Binghamton University BinghamtonNY13902 United States Department of Physics California Institute of Technology PasadenaCA91125 United States Scientific Research Division National Synchrotron Radiation Research Center Hsinchu30076 Taiwan Nano Science and Technology Taiwan International Graduate Program Academia Sinica National Taiwan University Taipei Taiwan Physics Division National Center for Theoretical Sciences Taipei10617 Taiwan Graduate Institute of Photonics and Optoelectronics National Taiwan University Taipei Taiwan

The identification of distinct charge transport features, deriving from nontrivial bulk band and surface states, has been a challenging subject in the field of topological systems. In topological Dirac and Weyl semimetals, nontrivial conical bands with Fermi-arc surface states give rise to negative longitudinal magnetoresistance due to chiral anomaly effect and unusual thickness dependent quantum oscillation from Weyl-orbit effect, which were demonstrated recently in experiments. In this work, we report the experimental observations of large nonlinear and nonreciprocal transport effects for both longitudinal and transverse channels in an untwinned Weyl metal of SrRuO3 thin film grown on a SrTiO3 substrate. From rigorous measurements with bias current applied along various directions with respect to the crystalline principal axes, the magnitude of nonlinear Hall signals from the transverse channel exhibits a simple sinα dependence at low temperatures, where α is the angle between bias current direction and orthorhombic [001]o, reaching a maximum when current is along orthorhombic [11¯0]o. On the contrary, the magnitude of nonlinear and nonreciprocal signals in the longitudinal channel attains a maximum for bias current along [001]o, and it vanishes for bias current along [11¯0]o. The observed α-dependent nonlinear and nonreciprocal signals in longitudinal and transverse channels reveal a magnetic Weyl phase with an effective Berry curvature dipole along [11¯0]o from surface states, accompanied by 1D chiral edge modes along [001]o Copyright © 2023, The Authors. All rights reserved.

关键词： Surface states