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THRESHOLD DYNAMICS FOR THE 3d RADIAL NLS WITH COMBINED NONLINEARITY

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arXiv 2023年

作者： Ardila, Alex H. Murphy, Jason Zheng, Jiqiang Department of Mathematics Universidade Federal de Minas Gerais ICEx-UFMG CEP MG 30123-970 Brazil Department of Mathematics & Statistics Missouri University of Science & Technology RollaMO United States Institute of Applied Physics and Computational Mathematics Beijing100088 China

We consider the nonlinear Schrödinger equation with focusing quintic and defocusing cubic nonlinearity in three space dimensions: (i∂t + ∆)u = |u|2u − |u|4u. In [18, 23], the authors classified the dynamics of solutions under the energy constraint E(u) c(W), where W is the quintic NLS ground state and Ec is the quintic NLS energy. In this work we classify the dynamics of H1 solutions at the threshold E(u) = Ec(W). Copyright © 2023, The Authors. All rights reserved.

关键词： Ground state

Massive Neutron Stars and White Dwarfs as Noncommutative Fuzzy Spheres

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arXiv 2022年

作者： Kalita, Surajit Mukhopadhyay, Banibrata Group Department of Mathematics & Applied Mathematics University of Cape Town Cape Town7700 South Africa Department of Physics Indian Institute of Science Bangalore560012 India

Over the last couple of decades, there are direct and indirect evidences for massive compact objects than their conventional counterparts. A couple of such examples are super-Chandrasekhar white dwarfs and massive neutron stars. The observations of more than a dozen peculiar over-luminous type Ia supernovae predict their origins from super-Chandrasekhar white dwarf progenitors. On the other hand, recent gravitational wave detection and some pulsar observations argue for massive neutron stars, lying in the famous mass-gap between lowest astrophysical black hole and conventional highest neutron star masses. We show that the idea of a squashed fuzzy sphere, which brings in noncommutative geometry, can self-consistently explain either of the massive objects as if they are actually fuzzy or squashed fuzzy spheres. Noncommutative geometry is a branch of quantum gravity. If the above proposal is correct, it will provide observational evidences for noncommutativity. Copyright © 2022, The Authors. All rights reserved.

关键词： Equations of state

Investigating the Constraints on Primordial Features with Future Cosmic Microwave Background and Galaxy Surveys

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arXiv 2022年

作者： Chandra, Debabrata Pal, Supratik Physics and Applied Mathematics Unit Indian Statistical Institute 203 B.T.Road Kolkata700108 India Technology Innovation Hub on Data Science Big Data Analytics and Data Curation Indian Statistical Institute 203 B.T.Road Kolkata700108 India

In this article, we do a thorough investigation of the competency of the forthcoming Cosmic Microwave Background (CMB) and Galaxy surveys in probing the features in the primordial power spectrum. Primordial features are specific model-dependent corrections on top of the standard power-law inflationary power spectrum;the functional form being given by different inflationary scenarios. Signature of any significant departure from the feature-less power spectrum will enable us to decipher the intricacies of the inflationary Universe. Here, we delve into three major yet distinct features, namely, Bump feature, Sharp feature signal, and Resonance feature signal. To analyse the features, we adopt a specific template for each feature model. We estimate the possible constraints on the feature parameters by employing Fisher matrix forecast analysis for the upcoming CMB missions such as CMB-S4, CORE-M5, LiteBIRD, PICO conjointly with DESI, and EUCLID galaxy surveys. To this end, we make use of four distinct observations to forecast on the bounds on the model parameters, namely, CMB, Baryon Acoustic Oscillations (BAO), Galaxy Clustering and Gravitational Weak Lensing or Cosmic Shear and their permissible synergy. For large scale structure (LSS) information, we consider different upper limits of scale for different redshifts for the purpose of circumventing the propagation of the errors stemming from the uncertainties on nonlinear scales into the constraints on the feature parameters. A comparative analysis of all three features has been done to estimate relative capabilities of these upcoming observations in shedding light on this crucial aspect of precision cosmology. Copyright © 2022, The Authors. All rights reserved.

关键词： Power spectrum

An Efficient Three-Factor Authenticated Key Agreement Technique Using FCM Under HC-IoT Architectures

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Computers, Materials & Continua 2022年第7期72卷 1373-1389页

作者： Chandrashekhar Meshram Agbotiname Lucky Imoize Sajjad Shaukat Jamal Parkash Tambare Adel R.Alharbi Iqtadar Hussain Department of Post Graduate Studies and Research in Mathematics Jayawanti Haksar Government Post-Graduation CollegeCollege of Chhindwara UniversityBetul460001M.P.India Department of Electrical and Electronics Engineering Faculty of EngineeringUniversity of LagosAkokaLagos100213Nigeria Department of Electrical Engineering and Information Technology Institute of Digital CommunicationRuhr University44801BochumGermany Department of Mathematics College of ScienceKing Khalid UniversityAbhaSaudi Arabia Water Resources&Applied Mathematics Research Lab Nagpur440027India College of Computing and Information Technology University of TabukTabuk71491Saudi Arabia Mathematics Program Department of MathematicsStatistics and PhysicsCollege of Arts and SciencesQatar University2713DohaQatar

The Human-Centered Internet of Things(HC-IoT)is fast becoming a hotbed of security and privacy *** users can establish a common session key through a trusted server over an open communication channel using a three-party authenticated key *** of the early authenticated key agreement systems relied on pairing,hashing,or modular exponentiation processes that are computationally intensive and *** order to address this problem,this paper offers a new three-party authenticated key agreement technique based on fractional chaotic *** new scheme uses fractional chaotic maps and supports the dynamic sensing of HC-IoT devices in the network architecture without a password *** projected security scheme utilized a hash function,which works well for the resource-limited HC-IoT *** results show that our new technique is resistant to password guessing attacks since it does not use a ***,our approach provides users with comprehensive privacy protection,ensuring that a user forgery attack causes no ***,our new technique offers better security features than the techniques currently available in the literature.

关键词： Three-party authenticated key agreement anonymity fractional chaotic maps Chebyshev polynomial password table human-centered internet of things(HC-IoT)

Age of Information Optimization Using a Hybrid Preemptive/Non-Preemptive Discipline

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Age of Information Optimization Using a Hybrid Preemptive/No...

IEEE Conference on Vehicular Technology (VTC)

作者： Tamer E. Fahim Sherif I. Rabia Ahmed H. Abd El-Malek Waheed K. Zahra Institute of Basic and Applied Sciences Egypt-Japan University of Science and Technology (E-JUST) Alexandria Egypt Department of Engineering Mathematics and Physics Faculty of Engineering Alexandria University Alexandria Egypt Department of Electronics and Communications Engineering Egypt-Japan University of Science and Technology (E-JUST) Alexandria Egypt Department of Engineering Physics and Mathematics Faculty of Engineering Tanta University Tanta Egypt

ISBN: (数字)9798331517786

ISBN: (纸本)9798331517793

Currently, the pervasive adoption of internet of things technology sheds light on the significance of real-time status update systems. The age of information (AoI) metric has been devised to reflect the strict information timeliness of such systems. Bufferless packet management scheme has demonstrated higher effectiveness in the AoI minimization. However, the existing preemptive (PR) and non-preemptive (NP) service disciplines operate independently of the system state, thereby reducing the system’s adaptability to varying system parameter settings, such as service time distribution and traffic loading condition. Therefore, we propose an elapsed-time-based hybrid PR/NP discipline to govern the service preemptions in a single-source M/Er/1/1 queueing scheme. The preemption is declined when the elapsed service time surpasses a predetermined threshold (controlling parameter). The average AoI is analyzed using the stochastic hybrid system approach. The numerical study demonstrated that the proposed discipline, owing to its threshold parameter, fulfills the optimality of the AoI performance, especially under highly dispersed Erlang service time distributions and higher traffic loading conditions.

关键词： Measurement Vehicular and wireless technologies Loading Stochastic processes Performance gain Information age Minimization Real-time systems Time factors Optimization

Two-mode terms in Wigner transport equation elucidate anomalous thermal transport in amorphous silicon

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Physical Review B 2025年第9期111卷 094206-094206页

作者： Jin Yang Xueyan Zhu Alan J. H. McGaughey Yee Sin Ang Wee-Liat Ong ZJU-UIUC Institute College of Energy Engineering Zhejiang University Jiaxing Haining Zhejiang 314400 China China Academy of Engineering Physics Software Center for High Performance Numerical Simulation Beijing 100088 China Institute of Applied Physics and Computational Mathematics Beijing 100088 China Department of Mechanical Engineering Carnegie Mellon University Pittsburgh Pennsylvania 15213 USA Science Mathematics and Technology Singapore University of Technology and Design 487372 Singapore State Key Laboratory of Clean Energy Utilization Zhejiang University Hangzhou Zhejiang 310027 China

Over the past decades, our understanding of thermal transport in amorphous materials has predominantly relied on the inherently harmonic Allen-Feldman theory, which has been found to be insufficient. In this study, the Wigner transport formalism is adopted to explicitly account for anharmonicity. In studying the thermal transport in amorphous silicon, the results highlight that amorphous materials are not generally computationally equivalent to crystals with disordered primitive cells. A method that leverages the properties of the two-mode terms in the Wigner transport formalism is proposed to predict the bulk thermal conductivity of amorphous materials using finite-size models. In doing so, the need for mode classification schemes required in the Allen-Feldman theory is eliminated, and similarities are discovered between the two-mode terms and the carriers commonly used to describe thermal transport in amorphous materials, i.e., propagons, diffusons, and locons. Two competing trends are identified that shed light on the recently discovered anomalous decrease in the high-temperature thermal conductivity in some amorphous materials.

关键词： Heat transfer

Electronic properties of 2D materials and their junctions

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Nano Materials science 2024年第1期6卷 1-23页

作者： Taposhree Dutta Neha Yadav Yongling Wu Gary J.Cheng Xiu Liang Seeram Ramakrishna Aoussaj Sbai Rajeev Gupta Aniruddha Mondal Zheng Hongyu Ashish Yadav Department of Chemistry Indian Institute of Engineering Science and TechnologyShibpurWest Bengal711103India Center for Advanced Laser Manufacturing(CALM) Shandong University of TechnologyZibo255000PR China School of Industrial Engineering Purdue University315 N.Grant St.West LafayetteIN47907United States Birck Nanotechnology Center Purdue University1205 W State St.West LafayetteIN47907United States Advanced Materials Institute Qilu University of TechnologyShandong Academy of SciencesJinan250014PR China Nanoscience and Nanotechnology Initiative National University of Singapore10 Kent Ridge Crescent119260Singapore Faculty of Applied Phsyics and Mathematics Gdansk University of Technology Narutowicza 11/1280233GdanskPoland Department of Physics School of EngineeringUniversity of Petroleum&Energy StudiesDehradun248007UttarakhandIndia Department of Physics National Institute of Technology DurgapurDurgapur713209West BengalIndia

With an extensive range of distinctive features at nano meter-scale thicknesses,two-dimensional(2D)materials drawn the attention of the scientific *** tremendous advancements in exploratory research on 2D materials,knowledge of 2D electrical transport and carrier dynamics still in its ***,here we highlighted the electrical characteristics of 2D materials with electronic band structure,electronic transport,dielectric constant,carriers *** atomic thinness of 2D materials makes substantially scaled field-effect transistors(FETs)with reduced short-channel effects conceivable,even though strong carrier mobility required for high performance,low-voltage device *** also discussed here about factors affecting 2D materials which easily enhanced the activity of those materials for various ***,Those 2D materials used in state-of-the-art electrical and optoelectronic devices because of the extensive nature of their electronic band structure.2D materials offer unprecedented freedom for the design of novel p-n junction device topologies in contrast to conventional bulk *** also,describe the numerous 2D p-n junctions,such as homo junction and hetero junction including mixed dimensional ***,we talked about the problems and potential for the future.

关键词： 2D materials Electrical properties p-n junctions Mixed hereto junctions Homo junctions Electrical transport

Dynamics of social interaction: Modeling the genesis of scientific collaboration

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Physical Review Research 2022年第4期4卷 L042001-L042001页

作者： Emma R. Zajdela Kimberly Huynh Andy T. Wen Andrew L. Feig Richard J. Wiener Daniel M. Abrams Department of Engineering Sciences and Applied Mathematics Northwestern University Evanston 60208 Illinois USA Research Corporation for Science Advancement Tucson 85712 Arizona USA Department of Industrial Engineering and Management Sciences Northwestern University Evanston 60208 Illinois USA Northwestern Institute for Complex Systems Northwestern University Evanston 60208 Illinois USA Department of Physics and Astronomy Northwestern University Evanston 60208 Illinois USA

Collaboration plays a key role in physics and in the broader scientific enterprise. Here we develop a mathematical model for predicting new collaborations. We demonstrate that a simple ordinary differential equation model is a good fit to a data set that tracks collaborations resulting from four series of annual conferences on diverse scientific topics, 12 conferences in total over a period of five years. The model, inspired by the physics of catalysis, attempts to quantify the time-varying probability that any pair of individuals will initiate a new collaboration. It takes as input the pair's prior familiarity with one another as well as their pattern of interaction over time, and incorporates the effect of temporally decaying memory. This model accurately reproduces the collaborations formed across all first-year conferences in the four series and outperforms seven other candidate models. We also find evidence that prescribed interaction can lead to novel team formation, with observed collaboration probabilities increased by almost an order of magnitude. These results suggest that encounters among individual researchers at conferences, including encounters engineered by organizers, play an important role in shaping the future of science.

关键词： Social system dynamics Social systems Collective dynamics Social dynamics Bifurcation analysis Chaos & nonlinear dynamics

BUILDING MACHINE LEARNING LIMITED AREA MODELS: KILOMETER-SCALE WEATHER FORECASTING IN REALISTIC SETTINGS

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arXiv 2025年

作者： Adamov, Simon Oskarsson, Joel Denby, Leif Landelius, Tomas Hintz, Kasper Christiansen, Simon Schicker, Irene Osuna, Carlos Lindsten, Fredrik Fuhrer, Oliver Schemm, Sebastian Federal Office for Meteorology and Climatology MeteoSwiss Institute of Atmospheric and Climate Science Department of Environmental Science ETH Zurich Switzerland Division of Statistics and Machine Learning Department of Computer and Information Science Linköping University Sweden Danish Meteorological Institute Swedish Meteorological and Hydrological Institute Sweden GeoSphere Austria Department of Applied Mathematics and Theoretical Physics University of Cambridge Cambridge United Kingdom

Machine learning is revolutionizing global weather forecasting, with models that efficiently produce highly accurate forecasts. Apart from global forecasting there is also a large value in high-resolution regional weather forecasts, focusing on accurate simulations of the atmosphere for a limited area. Initial attempts have been made to use machine learning for such limited area scenarios, but these experiments do not consider realistic forecasting settings and do not investigate the many design choices involved. We present a framework for building kilometer-scale machine learning limited area models with boundary conditions imposed through a flexible boundary forcing method. This enables boundary conditions defined either from reanalysis or operational forecast data. Our approach employs specialized graph constructions with rectangular and triangular meshes, along with multi-step rollout training strategies to improve temporal consistency. We perform systematic evaluation of different design choices, including the boundary width, graph construction and boundary forcing integration. Models are evaluated across both a Danish and a Swiss domain, two regions that exhibit different orographical characteristics. Verification is performed against both gridded analysis data and in-situ observations, including a case study for the storm Ciara in February 2020. Both models achieve skillful predictions across a wide range of variables, with our Swiss model outperforming the numerical weather prediction baseline for key surface variables. With their substantially lower computational cost, our findings demonstrate great potential for machine learning limited area models in the future of regional weather forecasting. Copyright © 2025, The Authors. All rights reserved.

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