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Physical Review A 2025年第1期111卷 013118-013118页

作者： Yu Kun Yang Xing Guang Su Kun Wang Yongjun Cheng Quan Wei Nan Zeqing Wang Danny L. Yeager Yong Wu Jian Guo Wang School of Physics Henan Normal University Xinxiang 453000 China Institute of Environmental Science Shanxi University Taiyuan 030006 China School of Physics and Information Technology Shaanxi Normal University Xi'an 710119 China Department of Physics Renmin University of China Beijing 100872 China Department of Chemistry Texas A&M University College Station Texas 77843 USA Institute of Applied Physics and Computational Mathematics P.O. Box 8009 Beijing 100088 China

Photodissociation cross sections of SiH+ have been explored within the uncoupled theoretical framework, notably in the work of Stancil et al. [Astrophys. J. 486, 574 (1997)]. However, in the SiH+ system, there are significant nonadiabatic interactions between the 31Π and 41Π states, which substantially affect the photodissociation process, particularly in the region between the Lyman α line and the Lyman limit. These nonadiabatic couplings give rise to numerous Feshbach resonances, significantly altering the final photodissociation cross sections. The present study highlights the critical importance of incorporating nonadiabatic electronic couplings to achieve accurate cross-section calculations. The results substantially enrich the data set on small molecular structures and spectra in interstellar clouds, providing essential theoretical support for future experimental investigations and for the modeling and analysis of stellar spectra. Additionally, this work offers key insights into the underlying physical mechanisms by which Feshbach resonances modulate line shapes in coupled photodissociation scattering cross sections.

关键词： Photodissociation

Cross-Modal Few-Shot Learning with Second-Order Neural Ordinary Differential Equations

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arXiv 2024年

作者： Zhang, Yi Cheng, Chun-Wun He, Junyi He, Zhihai Schönlieb, Carola-Bibiane Chen, Yuyan Aviles-Rivero, Angelica I. Harbin Institute of Technology China Department of Electrical and Electronic Engineering Southern University of Science and Technology China Department of Applied Mathematics and Theoretical Physics University of Cambridge United Kingdom Pengcheng Laboratory China Shanghai Key Laboratory of Data Science School of Computer Science Fudan University China Yau Mathematical Sciences Center Tsinghua University China

We introduce SONO, a novel method leveraging Second-Order Neural Ordinary Differential Equations (Second-Order NODEs) to enhance cross-modal few-shot learning. By employing a simple yet effective architecture consisting of a Second-Order NODEs model paired with a cross-modal classifier, SONO addresses the significant challenge of overfitting, which is common in few-shot scenarios due to limited training examples. Our second-order approach can approximate a broader class of functions, enhancing the model’s expressive power and feature generalization capabilities. We initialize our cross-modal classifier with text embeddings derived from class-relevant prompts, streamlining training efficiency by avoiding the need for frequent text encoder processing. Additionally, we utilize text-based image augmentation, exploiting CLIP’s robust image-text correlation to enrich training data significantly. Extensive experiments across multiple datasets demonstrate that SONO outperforms existing state-of-the-art methods in few-shot learning performance. Copyright © 2024, The Authors. All rights reserved.

关键词： Zero-shot learning

Mechanically Laser-Induced Acoustic Cavitation in Viscoelastic Tissue: Theoretical Study

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Bulletin of the Russian Academy of sciences: physics 2023年第Suppl 3期87卷 S348-S355页

作者： Zain Abu Shaeer Amerah M. Hakami Abu-Bakr, Ali F. Ahmed K. Abu-Nab Department of Basic Science Higher Institute of Engineering and Technology Kafrelsheikh33511 Egypt Department of Mathematics Faculty of Science Jazan University Jazan82723 Saudi Arabia Department of Mathematics and Computer Science Faculty of Science Menoufia University Shebin El-Koom32511 Egypt Phystech School of Applied Mathematics and Informatics Moscow Institute of Physics and Technology Moscow oblast Dolgoprudny141700 Russia

Abstract: Laser-induced acoustic cavitation microbubble dynamics have exhibited significant development in biological systems such as lithotripsy. Investigating the mechanically laser-induced acoustic cavitation microbubble in viscoelastic tissue is the goal of this work. Based on surface tension and viscous forces, the laser-induced cavitation model (also known as the modified Rayleigh–Plesset model), the theoretical model is developed and numerically solved using exponential cubic B-spline Collocation Method. In addition, the energy released in viscoelastic tissue by laser-induced acoustic cavitation as well as mechanically induced cavitation is investigated. The findings of our work provide valuable insight into the application of laser-induced acoustic cavitation microbubbles such as kidney stones and lithotripsy. © Pleiades Publishing, Ltd. 2023. ISSN 1062-8738, Bulletin of the Russian Academy of sciences: physics, 2023, Vol. 87, Suppl. 3, pp. S348–S355. Pleiades Publishing, Ltd., 2023. ISSN 1062-8738, Bulletin of the Russian Academy of sciences: physics, 2023. Pleiades Publishing, Ltd., 2023.

关键词： Tissue

PVC reinforced with Pb1/2Ni1/2Fe2O4 spinel ferrites nanoparticles: development of linear/nonlinear optical, dielectric characteristics and γ-rays buildup-factors of for optical and radiation safety applications

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Optical and Quantum Electronics 2025年第1期57卷 1-21页

作者： Alfryyan, Nada Alsaif, Norah A. M. Khattari, Z.Y. Al-Ghamdi, Hanan Elsad, R.A. Shams, M.S. El-Refaey, Adel M. Abouhaswa, A.S. Elamy, Mamdouh I. Rammah, Y.S. Department of Physics College of Science Princess Nourah Bint Abdulrahman University P.O. Box 84428 Riyadh11671 Saudi Arabia Department of Physics Faculty of Science The Hashemite University P. O. Box 330127 Zarqa13133 Jordan Basic Engineering Science Department Faculty of Engineering Menoufia University Shebin El-Koom32511 Egypt Department of Basic and Applied Science Collage of Engineering and Technology Arab Academy of Science Technology and Maritime Transport Smart Village Giza Egypt Physics and Mathematical Engineering Department Faculty of Electronic Engineering Menoufia University 32952 Menouf Egypt Department of Physics Faculty of Science Menoufia University Shebin El-Koom32511 Egypt Institute of Natural Science and Mathematics Ural Federal University Ekaterinburg620002 Russia Industrial Engineering Department College of Engineering Northern Border University Arar Saudi Arabia Department of Production Engineering and Mechanical Design Faculty of Engineering Menoufia University Shebin El‑Kom Egypt Pharos University in Alexandria Canal El Mahmoudia Street Beside Green Plaza Complex Alexandria21648 Egypt

Physical, linear/nonlinear optical, dielectric characteristics, and γ-ray-buildup factors of nanocomposites (NCs) sheets of PVC doped with x(Pb0.5Ni0.5Fe2O4) spinel nanoferrites: x = 0–10 wt% and named as PVC/PNF0-PVC/PNF10 have been tested. Density (ρ) changed from 1.405 g·cm−3 to 2.6130 g·cm−3 as x changed from 0.0 to 10 wt%. Optical-energy-gap (Eoptical) diminished from 5.207 to 2.753 eV, whereas the linear index of refraction of (nlinear) increased from 1.962 to 2.405 for PVC/PNF0 and PVC/PNF10 NCs sheets. The nonlinear optical susceptibility (χ3) and nonlinear refractive index (n2optical) of the investigated PVC/PNF-NCs sheets increased as (Pb0.5Ni0.5Fe2O4) content increased. Dielectric spectroscopy of fabricated PVC/PNF-NCs is investigated throughout frequencies from 50 Hz to 5 × 106 Hz at RT. The dielectric-constant was reduced by introduction of Pb0.5Ni0.5Fe2O4. Mass absorption coefficient (MAC) values of PVC/PNF-NCs sheets obeyed the fact that (PVC/PNF0)MAC MAC MAC MAC MAC. The γ-ray exposure, and absorption-buildup factors of the investigated PVC/PNF-NCs sheets followed as (PVC/PNF0)EBF/EABF > (PVC/PNF1)EBF/EABF > (PVC/PNF3)EBF/EABF > (PVC/PNF5)EBF/EABF > (PVC/PNF10)EBF/EABF. Results confirmed that the suggested PVC/PNF-NCs sheets with smallest dielectric constant may implement in electrical cable. Also, PVC/PNF-NCs sheets may implement optical, electrical devices and γ-ray attenuation field. © The Author(s), under exclusive licence to Springer science+Business Media, LLC, part of Springer Nature 2024.

关键词： Gamma ray production

A possible late-time transition of MB inferred via neural networks

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arXiv 2024年

作者： Mukherjee, Purba Dialektopoulos, Konstantinos F. Said, Jackson Levi Mifsud, Jurgen Centre for Theoretical Physics Jamia Millia Islamia New Delhi110025 India Physics and Applied Mathematics Unit Indian Statistical Institute Kolkata700108 India Department of Mathematics and Computer Science Transilvania University of Brasov Eroilor 29 Brasov Romania Institute of Space Sciences and Astronomy University of Malta Msida Malta

The strengthening of tensions in the cosmological parameters has led to reconsidering the fundamental aspects of standard cosmology. The tension in the Hubble constant can also be viewed as a tension between local and early Universe constraints on the absolute magnitude MB of Type Ia supernova. In this work, we reconsider the possibility of a variation of this parameter in a model-independent way. We employ neural networks to agnostically constrain the value of the absolute magnitude as well as assess the impact and statistical significance of a variation in MB with redshift from the Pantheon+ compilation, together with a thorough analysis of the neural network architecture. We find an indication for a possible transition redshift at the z ≈ 1 region. Copyright © 2024, The Authors. All rights reserved.

关键词： Cosmology

Riemann-Liouville fractional Brownian motion with random Hurst exponent

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arXiv 2024年

作者： Woszczek, Hubert Wylomańska, Agnieszka Chechkin, Aleksei Faculty of Pure and Applied Mathematics Hugo Steinhaus Center Wroclaw University of Science and Technology Wroclaw50-370 Poland Institute for Physics & Astronomy University of Potsdam Golm Potsdam14476 Germany 06120 Germany

We examine two stochastic processes with random parameters, which in their basic versions (i.e., when the parameters are fixed) are Gaussian and display long range dependence and anomalous diffusion behavior, characterized by the Hurst exponent. Our motivation comes from biological experiments, which show that the basic models are inadequate for accurate description of the data, leading to modifications of these models in the literature through introduction of the random parameters. The first process, fractional Brownian motion with random Hurst exponent (referred to as FBMRE below) has been recently studied, while the second one, Riemann-Liouville fractional Brownian motion with random exponent (RL FBMRE) has not been explored. To advance the theory of such doubly stochastic anomalous diffusion models, we investigate the probabilistic properties of RL FBMRE and compare them to those of FBMRE. Our main focus is on the autocovariance function and the time-averaged mean squared displacement (TAMSD) of the processes. Furthermore, we analyze the second moment of the increment processes for both models, as well as their ergodicity properties. As a specific case, we consider the mixture of two point distributions of the Hurst exponent, emphasizing key differences in the characteristics of RL FBMRE and FBMRE, particularly in their asymptotic behavior. The theoretical findings presented here lay the groundwork for developing new methods to distinguish these processes and estimate their parameters from experimental data. © 2024, CC BY.

关键词： Stochastic systems

INITIAL BOUNDARY VALUE PROBLEM FOR THE 3D MAGNETIC-CURVATURE-DRIVEN RAYLEIGH-TAYLOR MODEL

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Acta Mathematica Scientia 2020年第2期40卷 529-542页

作者： Xueke PU Boling GUO School of Mathematics and Information Science Guangzhou UniversityGuangzhou 510006China Institute of Applied Physics and Computational Mathematics P.O.Box 8009Beijing 100088China

This article studies the initial-boundary value problem for a three dimensional magnetic-curvature-driven Rayleigh-Taylor *** first obtain the global existence of weak solutions for the full model equation by employing the Galerkin’s approximation ***,for a slightly simplified model,we show the existence and uniqueness of global strong solutions via the Banach’s fixed point theorem and vanishing viscosity method.

关键词： Magnetic-curvature-driven Rayleigh-Taylor model weak solutions strong solutions Banach fixed point theorem vanishing viscosity method

Study on the optical mechanism of photorefractive resistance in Zr-doped lithium niobate crystals from first-principle calculations

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Physical chemistry chemical physics : PCCP 2024年第48期26卷 29922-29928页

作者： Weiwei Wang Hongde Liu Dahuai Zheng Yue Liu Yongfa Kong Jingjun Xu Department of Mathematics and Physics Shijiazhuang Tiedao University Shijiazhuang 050043 China. MOE Key Laboratory of Weak-Light Nonlinear Photonics TEDA Institute of Applied Physics and School of Physics Nankai University Tianjin 300457 China. liuhd97@***. College of materials Science and Engineering Liaoning Technical University Liaoning 123032 China.

Lithium niobate on insulator (LNOI) has attracted widespread interest due to the excellent optical performance of lithium niobate crystals and the integration characteristics of thin film devices. With the improvement of the integration level of photonic integrated chips and the increase in light intensity inside the chip, the impact of optical damage in LNOI on-chip performance has attracted attention. One effective way to suppress the optical damage of lithium niobate is to dope it with Zr to form LiNbO (LiNbO:Zr), which is famous for its high resistance to optical damage from ultraviolet to visible spectrum. However, the mechanism behind the outstanding resistance to optical damage in LiNbO:Zr is still unclear. Here, the density of states, photorefractive center, refractive index, and birefringence of LiNbO:Zr are analyzed as functions of dopant concentrations by first-principle calculations. Electronic property analysis shows that the electrons in the Zr 4d state are all transferred to the Nb 4d state, occupying the shallow impurity level. The refractive index and birefringence change when the doping concentration reaches a threshold concentration of about 2.0 mol%. As the most stable full shell state, Zr-Nb can effectively suppress the photorefractive effect and result in the lowest refractive index and birefringence. These calculations not only establish the defect model corresponding to the different doping concentrations to investigate the optical properties of LN:Zr but also explain the mechanism underlying the high resistance to optical damage in LiNbO:Zr.

关键词：

Electronic processes in collisions between nitrogen ions and hydrogen atoms

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arXiv 2024年

作者： Jia, C.C. Qi, Y.Y. Niu, J.J. Wu, Y. Wang, J.G. Dubois, A. Sisourat, N. Gao, J.W. School of Physics Hangzhou Normal University Hangzhou311121 China Key Laboratory of Computational Physics Institute of Applied Physics and Computational Mathematics Beijing100088 China Sorbonne Université CNRS UMR 7614 Laboratoire de Chimie Physique-Matière et Rayonnement Paris75005 France College of Data Science Jiaxing University Jiaxing314001 China

In order to interpret and predict the behavior and properties of fusion plasma, accurate cross sections for electronic processes in collisions between plasma impurities and atomic hydrogen are required. In this work, we investigate the electron capture (or charge exchange), target excitation, and ionization processes occurring in collision of N4+ with atomic hydrogen in a broad energy domain ranging from 0.06 to 225 keV/u. We consider N4+ ground state N4+(2s) and also N4+(2p) since the impurities in the edge plasma environment may be excited due to collisions with electrons and ions/atoms. Total and partial cross sections in both spin-averaged and spin-resolved cases are calculated using a two-active-electron semiclassical asymptotic-state close-coupling approach. For electron capture cross sections the present results show the best overall agreement with available experimental data for both total and partial cross sections, and the origins of observed discrepancies are discussed. Furthermore, we provide new data for target excitation and ionization processes, which are essential to improve our understanding of this relevant collision system. © 2024, CC BY.

关键词： Ground state

On variants of multivariate quantum signal processing and their characterizations

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arXiv 2023年

作者： Németh, Balázs Kövér, Blanka Kulcsár, Boglárka Miklósi, Roland Botond Gilyén, András Department of Applied Mathematics and Theoretical Physics University of Cambridge United Kingdom Institute of Mathematics Faculty of Science Eötvös Loránd University Budapest Hungary Alfréd Rényi Institute of Mathematics HUN-REN Budapest Hungary

Quantum signal processing (QSP) is a highly successful algorithmic primitive in quantum computing which leads to conceptually simple and efficient quantum algorithms using the block-encoding framework of quantum linear algebra. Multivariate variants of quantum signal processing (MQSP) could be a valuable tool in extending earlier results via implementing multivariate (matrix) polynomials. However, MQSP remains much less understood than its single-variate version lacking a clear characterization of "achievable" multivariate polynomials. We show that Haah’s characterization of general univariate QSP can be extended to homogeneous bivariate (commuting) quantum signal processing. We also show a similar result for an alternative inhomogeneous variant when the degree in one of the variables is at most 1, but construct a counterexample where both variables have degree 2, which in turn refutes an earlier characterization proposed / conjectured by Rossi and Chuang for a related restricted class of MQSP. Finally, we describe homogeneous multivariate (non-commuting) QSP variants that break away from the earlier two-dimensional treatment limited by its reliance on Jordan-like decompositions, and might ultimately lead to the development of novel quantum algorithms. Copyright © 2023, The Authors. All rights reserved.

关键词： Linear algebra