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SSRN 2024年

作者： AbuGhanem, Muhammad Homid, Ali H. Obada, A.S.-F. Hendy, Ahmed S. Eleuch, Hichem Faculty of Science Ain Shams University Cairo11566 Egypt Zewail City of Science Technology and Innovation Giza12678 Egypt Mathematics Department Faculty of Science Al-Azhar University Assiut71524 Egypt Mathematics Department Faculty of Science Al-Azher University Nassr City Cairo11884 Egypt Department of Computational Mathematics and Computer Science Institute of Natural Sciences and Mathematics Ural Federal University Yekaterinburg Russia Department of Mathematics Faculty of Science Benha University Benha Egypt Department of Applied Physics and Astronomy University of Sharjah Sharjah27272 United Arab Emirates College of Arts and Sciences Abu Dhabi University Abu Dhabi59911 United Arab Emirates Institute for Quantum Science and Engineering Texas A&M University College StationTX77843 United States

Universal quantum gates are crucial for efficient algorithm execution on quantum computers, offering rapid and fault-tolerant manipulations. This paper presents a theoretical framework for realizing a novel entangling universal quantum gate within the circuit quantum electrodynamics (circuit QED) architecture. Our approach involves positioning two SQUIDs qubits within a resonant single-mode microwave cavity field, enabling the implementation of the SQSCZ gate, a fusion of the square root of SWAP ($\sqrt{SWAP}$) and the square root of controlled-Z ($\sqrt{CZ}$) gates. This gate serves as a fundamental building block for constructing universal quantum gates including the controlled-NOT gates. Moreover, the SQSCZ gate operates unitarily, ensuring logical reversibility, and exhibits an entangling power (EP) of 1.5/9. Quantitative analysis reveals an average gate fidelity of $60\%$. To delve deeper into the gate's performance, we conducted quantum process tomography (QPT) analysis by repeating the quantum experiment 11,000 times for each measurement basis on an IBM Quantum's quantum simulator. This rigorous approach yielded a remarkable process fidelity of $96.065616\%$. These findings offer promising implications for future research and applications. © 2024, The Authors. All rights reserved.

关键词： Qubits

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DeePKS: A comprehensive data-driven approach towards chemically accurate density functional theory

arXiv

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arXiv 2020年

作者： Chen, Yixiao Zhang, Linfeng Wang, Han Weinan, E. Program in Applied and Computational Mathematics Princeton University PrincetonNJ United States Laboratory of Computational Physics Institute of Applied Physics and Computational Mathematics Huayuan Road 6 Beijing100088 China Department of Mathematics Princeton University PrincetonNJ United States

We propose a general machine learning-based framework for building an accurate and widely-applicable energy functional within the framework of generalized Kohn-Sham density functional theory. To this end, we develop a way of training self-consistent models that are capable of taking large datasets from different systems and different kinds of labels. We demonstrate that the functional that results from this training procedure gives chemically accurate predictions on energy, force, dipole, and electron density for a large class of molecules. It can be continuously improved when more and more data are available. Copyright © 2020, The Authors. All rights reserved.

关键词： Large dataset

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Regimes of stratified turbulence at low Prandtl number

arXiv

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arXiv 2023年

作者： Shah, Kasturi Chini, Gregory P. Caulfield, Colm-Cille P. Garaud, Pascale Department of Applied Mathematics and Theoretical Physics University of Cambridge CambridgeCB3 0WA United Kingdom Department of Earth Atmospheric and Planetary Sciences Massachusetts Institute of Technology CambridgeMA02139 United States Program in Integrated Applied Mathematics University of New Hampshire DurhamNH03824 United States Department of Mechanical Engineering University of New Hampshire DurhamNH03824 United States Institute for Energy and Environmental Flows University of Cambridge CambridgeCB3 0EZ United Kingdom Department of Applied Mathematics Baskin School of Engineering University of California Santa Cruz Santa CruzCA95064 United States

Quantifying transport by strongly stratified turbulence in low Prandtl number (Pr) fluids is critically important for the development of better models for the structure and evolution of stellar and planetary interiors. Motivated by recent numerical simulations showing strongly anisotropic flows suggestive of scale-separated dynamics, we perform a multiscale asymptotic analysis of the governing equations. We find that, in all cases, the resulting slow-fast systems take a quasilinear form. Our analysis also reveals the existence of several distinct dynamical regimes depending on the emergent buoyancy Reynolds and Péclet numbers, Reb = α2Re and Peb = PrReb, respectively, where α is the aspect ratio of the large-scale turbulent flow structures, and Re is the outer scale Reynolds number. Scaling relationships relating the aspect ratio, the characteristic vertical velocity, and the strength of the stratification (measured by the Froude number Fr) naturally emerge from the analysis. When Peb α, the dynamics at all scales is dominated by buoyancy diffusion, and our results recover the scaling laws empirically obtained from direct numerical simulations by Cope et al. (2020). For Peb ≥ O(1), diffusion is negligible (or at least subdominant) at all scales and our results are consistent with those of Chini et al. (2022) for strongly stratified geophysical turbulence at Pr = O(1). Finally, we have identified a new regime for α Peb 1, in which slow, large scales are diffusive while fast, small scales are not. We conclude by presenting a map of parameter space that clearly indicates the transitions between isotropic turbulence, non-diffusive stratified turbulence, diffusive stratified turbulence and viscously-dominated flows, and by proposing parameterisations of the buoyancy flux, mixing efficiency and turbulent diffusion coefficient for each regime. © 2023, CC BY.

关键词： Buoyancy

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Bayesian calibration of viscous anisotropic hydrodynamic simulations of heavy-ion collisions

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Physical Review C 2023年第5期108卷 054905-054905页

作者： Dananjaya Liyanage Özge Sürer Matthew Plumlee Stefan M. Wild Ulrich Heinz Department of Physics The Ohio State University Columbus Ohio 43210 USA Department of Information Systems and Analytics Miami University Oxford Ohio 45056 USA Northwestern-Argonne Institute of Science and Engineering (NAISE) Northwestern University Evanston Illinois 60208 USA Industrial Engineering and Management Sciences Department Northwestern University Evanston Illinois 60208 USA Applied Mathematics & Computational Research Division Lawrence Berkeley National Laboratory Berkeley California 94720 USA

Owing to large pressure gradients at early times, standard hydrodynamic model simulations of relativistic heavy-ion collisions do not become reliable until O(1) fm/c after the collision. To address this one often introduces a prehydrodynamic stage that models the early evolution microscopically, typically as a conformal, weakly interacting gas. In such an approach the transition from the prehydrodynamic to the hydrodynamic stage is discontinuous, introducing considerable theoretical model ambiguity. Alternatively, fluids with large anisotropic pressure gradients can be handled macroscopically using the recently developed viscous anisotropic hydrodynamics (VAH). In high-energy heavy-ion collisions VAH is applicable already at very early times, and at later times transitions smoothly into conventional second-order viscous hydrodynamics. We present a Bayesian calibration of the VAH model with experimental data for Pb-Pb collisions at the LHC at sNN=2.76 TeV. We find that the VAH model has the unique capability of constraining the specific viscosities of the quark-gluon plasma at higher temperatures than other previously used models.

关键词： Charged-particle multiplicity Collective flow Quark-gluon plasma Relativistic heavy-ion collisions Transport in heavy-ion collisions

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Real-space investigation of polarons in hematite Fe2O3

arXiv

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arXiv 2023年

作者： Redondo, Jesus Reticcioli, Michele Gabriel, Vit Wrana, Dominik Ellinger, Florian Riva, Michele Franceschi, Giada Rheinfrank, Erik Sokolovic, Igor Jakub, Zdenek Kraushofer, Florian Alexander, Aji Patera, Laerte L. Repp, Jascha Schmid, Michael Diebold, Ulrike Parkinson, Gareth S. Franchini, Cesare Kocan, Pavel Setvin, Martin Department of Surface and Plasma Science Faculty of Mathematics and Physics Charles University Prague180 00 Czech Republic Institute of Applied Physics TU Wien Vienna1040 Austria Institute of Physics Czech Academy of Sciences Cukrovarnická 10 Prague 6162 00 Czech Republic University of Vienna Faculty of Physics Center for Computational Materials Science Vienna Austria Institute of Experimental and Applied Physics University of Regensburg Regensburg93040 Germany Institute of Physical Chemistry University of Innsbruck Innsbruck6020 Austria Dipartimento di Fisica e Astronomia Università di Bologna Bologna40127 Italy

In polarizable materials, electronic charge carriers interact with the surrounding ions, leading to quasiparticle behaviour. 1,2 The resulting polarons play a central role in many materials properties including electrical transport, 3-5 optical properties, 6 surface reactivity7,8 and magnetoresistance, 9,10 and polaron properties are typically investigated indirectly through such macroscopic characteristics. Here, noncontact atomic force microscopy (nc-AFM) 11 is used to directly image polarons in Fe2O3 at the single quasiparticle limit. A combination of Kelvin probe force microscopy (KPFM) 12 and kinetic Monte Carlo (KMC) simulations shows that Ti doping dramatically enhances the mobility of electron polarons, and density functional theory (DFT) calculations indicate that a metallic transition state is responsible for the enhancement. In contrast, hole polarons are significantly less mobile and their hopping is hampered further by the introduction of trapping centres. © 2023, CC BY.

关键词： Polarons

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A quasi-conservative DG-ALE method for multi-component flows using the non-oscillatory kinetic flux

arXiv

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arXiv 2021年

作者： Luo, Dongmi Li, Shiyi Huang, Weizhang Qiu, Jianxian Chen, Yibing Institute of Applied Physics and Computational Mathematics Beijing100088 China Institute of Applied Physics and Computational Mathematics Beijing100088 China Department of Mathematics University of Kansas LawrenceKS66045 United States School of Mathematical Sciences Fujian Provincial Key Laboratory of Mathematical Modeling and High-Performance Scientific Computing Xiamen University XiamenFujian361005 China

A high-order quasi-conservative discontinuous Galerkin (DG) method is proposed for the numerical simulation of compressible multi-component flows. A distinct feature of the method is a predictor-corrector strategy to define the grid velocity. A Lagrangian mesh is first computed based on the flow velocity and then used as an initial mesh in a moving mesh method (the moving mesh partial differential equation or MMPDE method) to improve its quality. The fluid dynamic equations are discretized in the direct arbitrary Lagrangian-Eulerian framework using DG elements and the non-oscillatory kinetic flux while the species equation is discretized using a quasi-conservative DG scheme to avoid numerical oscillations near material interfaces. A selection of one- and two-dimensional examples are presented to verify the convergence order and the constant-pressure-velocity preservation property of the method. They also demonstrate that the incorporation of the Lagrangian meshing with the MMPDE moving mesh method works well to concentrate mesh points in regions of shocks and material interfaces. Copyright © 2021, The Authors. All rights reserved.

关键词： Galerkin methods

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Thermal Conductivity of Water at Extreme Conditions

arXiv

引用

arXiv 2023年

作者： Zhang, Cunzhi Puligheddu, Marcello Zhang, Linfeng Car, Roberto Galli, Giulia Pritzker School of Molecular Engineering University of Chicago ChicagoIL60637 United States Materials Science Division Center for Molecular Engineering Argonne National Laboratory LemontIL60439 United States Program in Applied and Computational Mathematics Princeton University PrincetonNJ08544 United States Department of Chemistry Department of Physics Princeton Institute for the Science and Technology of Materials Princeton University PrincetonNJ08544 United States Department of Chemistry University of Chicago ChicagoIL60637 United States

Measuring the thermal conductivity (κ) of water at extreme conditions is a challenging task and few experimental data are available. We predict κ for temperatures and pressures relevant to the conditions of the Earth mantle, between 1,000 and 2,000 K and up to 22 GPa. We employ close to equilibrium molecular dynamics simulations and a deep neural network potential fitted to density functional theory data. We then interpret our results by computing the equation of state of water on a fine grid of points and using a simple model for κ. We find that the thermal conductivity is weakly dependent on temperature and monotonically increases with pressure with an approximate square-root behavior. In addition we show how the increase of κ at high pressure, relative to ambient conditions, is related to the corresponding increase in the sound velocity. Although the relationships between the thermal conductivity, pressure and sound velocity established here are not rigorous, they are sufficiently accurate to allow for a robust estimate of the thermal conductivity of water in a broad range of temperatures and pressures, where experiments are still difficult to perform. Copyright © 2023, The Authors. All rights reserved.

关键词： Thermal conductivity

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computational Design of Anisotropic Stealthy Hyperuniform Composites with Engineered Directional Scattering Properties

arXiv

引用

arXiv 2023年

作者： Shi, Wenlong Keeney, David Chen, Duyu Jiao, Yang Torquato, Salvatore Materials Science and Engineering Arizona State University TempeAZ85287 United States Materials Research Laboratory University of California Santa BarbaraCA93106 United States Department of Physics Arizona State University TempeAZ85287 United States Department of Chemistry Princeton University PrincetonNJ08544 United States Department of Physics Princeton University PrincetonNJ08544 United States Princeton Institute of Materials Princeton University PrincetonNJ08544 United States Program in Applied and Computational Mathematics Princeton University PrincetonNJ08544 United States

Disordered hyperuniform materials are an emerging class of exotic amorphous states of matter that endow them with singular physical properties, including large isotropic photonic band gaps, superior resistance to fracture, and nearly optimal electrical and thermal transport properties, to name but a few. Here, we generalize the Fourier-space based numerical construction procedure for designing and generating digital realizations of isotropic disordered hyperuniform two-phase heterogeneous materials (i.e., composites) developed by Chen and Torquato [Acta Mater. 142, 152 (2018)] to anisotropic microstructures with targeted spectral densities. Our generalized construction procedure explicitly incorporates the vector-dependent spectral density function χ˜V (k) of arbitrary form that is realizable. We demonstrate the utility of the procedure by generating a wide spectrum of anisotropic stealthy hyperuniform (SHU) microstructures with χ˜V (k) = 0 for k ∈ Ω, i.e., complete suppression of scattering in an "exclusion" region Ω around the origin in the Fourier space. We show how different exclusion-region shapes with various discrete symmetries, including circular-disk, elliptical-disk, square, rectangular, butterfly-shaped and lemniscate-shaped regions of varying size, affect the resulting statistically anisotropic microstructures as a function of the and phase volume fraction. The latter two cases of Ω lead to directionally hyperuniform composites, which are stealthy hyperuniform only along certain directions, and are non-hyperuniform along others. We find that, while the circular-disk exclusion regions give rise to isotropic hyperuniform composite microstructures, the directional hyperuniform behaviors imposed by the shape asymmetry (or anisotropy) of certain exclusion regions give rise to distinct anisotropic structures and degree of uniformity in the distribution of the phases on intermediate and large length scales along different directions. Moreover, while the anisotr

关键词： Volume fraction

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Direct Statistical Simulation of the Busse Annulus

arXiv

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arXiv 2022年

作者： Oishi, Jeffrey S. Burns, Keaton J. Marston, J.B. Tobias, Steven M. Department of Physics & Astronomy Bates College LewistonME04240 United States Department of Mathematics Massachusetts Institute of Technology CambridgeMA02138 United States Center For Computational Astrophysics Flatiron Institute New YorkNY10010 United States Department of Physics Brown Theoretical Physics Center Brown University ProvidenceRI02912 United States Department of Applied Mathematics University of Leeds LeedsLS2 9JT United Kingdom

We consider direct statistical simulation (DSS) of a paradigm system of convection interacting with mean flows. In the Busse Annulus model zonal jets are generated through the interaction of convectively driven turbulence and rotation;non-trivial dynamics including the emergence of multiple jets and bursting 'predator-prey' type dynamics can be found. We formulate the DSS by expanding around the mean flow in terms of equal-time cumulants and arrive at a closed set of equations of motion for the cumulants. Here, we present results using an expansion terminated at the second cumulant (CE2);it is fundamentally a quasi-linear theory. We focus on particular cases including bursting and bistable multiple jets and demonstrate that CE2 can reproduce the results of direct numerical simulation if particular attention is given to symmetry considerations. © 2022, CC BY-NC-ND.

关键词： Equations of motion

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Linear Combination of Hamiltonian Simulation for Nonunitary Dynamics with Optimal State Preparation Cost

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Physical Review Letters 2023年第15期131卷 150603-150603页

作者： Dong An Jin-Peng Liu Lin Lin Joint Center for Quantum Information and Computer Science University of Maryland College Park Maryland 20742 USA Department of Mathematics University of California Berkeley California 94720 USA Simons Institute for the Theory of Computing University of California Berkeley California 94720 USA Center for Theoretical Physics Massachusetts Institute of Technology Cambridge Massachusetts 02139 USA Lawrence Berkeley National Laboratory Applied Mathematics and Computational Research Division Berkeley California 94720 USA Challenge Institute for Quantum Computation University of California Berkeley California 94720 USA

We propose a simple method for simulating a general class of nonunitary dynamics as a linear combination of Hamiltonian simulation (LCHS) problems. LCHS does not rely on converting the problem into a dilated linear system problem or on the spectral mapping theorem. The latter is the mathematical foundation of many quantum algorithms for solving a wide variety of tasks involving nonunitary processes, such as the quantum singular value transformation. The LCHS method can achieve optimal cost in terms of state preparation. We also demonstrate an application for open quantum dynamics simulation using the complex absorbing potential method with near-optimal dependence on all parameters.

关键词： Open quantum systems Quantum algorithms Quantum algorithms & computation Quantum simulation Differential equations

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