Article
Mathematics, Interdisciplinary Applications
Muhammad Yaseen, Qamar Un Nisa Arif, Reny George, Sana Khan
Summary: This study numerically addresses the time fractional Cattaneo equation involving Caputo-Fabrizio derivative using spline-based numerical techniques. The proposed schemes are stable and convergent, and the efficiency of the schemes is demonstrated through numerical studies.
FRACTAL AND FRACTIONAL
(2022)
Article
Mathematics, Applied
Gang Yang, Jian Zhang
Summary: This paper studies the existence and asymptotic analysis of ground states for the nonlinear Dirac equation with a singular potential. By using variational tools from the non-Nehari manifold method under the asymptotically periodic condition, we establish a global compactness result and prove the existence of ground state solution, the continuous dependence of ground state energy on the parameter, and the asymptotic convergence of solutions.
APPLIED MATHEMATICS LETTERS
(2022)
Article
Mathematics
Elena Danesi
Summary: In this paper, we continue the analysis of the dispersive properties of the 2D and 3D massless Dirac-Coulomb equations that has been started in [7] and [8]. We prove a priori estimates of the mentioned systems' solutions, particularly Strichartz estimates with an additional angular regularity, using the tools developed in previous works. As an application, we demonstrate local well-posedness results for a Dirac-Coulomb equation perturbed with Hartree-type nonlinearities.
JOURNAL OF FUNCTIONAL ANALYSIS
(2024)
Article
Chemistry, Physical
Mikulas Matousek, Michal Hapka, Libor Veis, Katarzyna Pernal
Summary: A multiconfigurational adiabatic connection (AC) formalism is an attractive approach to compute the dynamic correlation within DMRG models. The study investigates the effect of removing the fixed-RDM approximation in AC and finds that lifting this approximation is a viable way toward improving the accuracy of existing AC approximations.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Physics, Multidisciplinary
S. A. Bruce
Summary: In this research, the Dirac Kepler/Coulomb (KC) problem in (2 + 1)-dimensions with a position-dependent effective mass term was investigated. By examining two instances in polar coordinates, two different relativistic quantum-mechanical models were presented, involving the quantum dynamics of an electron in the presence of Coulomb potential and a Coulomb-like scalar potential, as well as the planar dynamics of a self-interacting electron in a Coulomb potential with nonlinearities introduced via a scalar self-interaction.
Article
Optics
Saad Mehmood, Eva Lindroth, Luca Argenti
Summary: The ionization of atoms with attosecond pulses generates entangled excited ionic states and photoelectrons, which can be controlled through laser parameters. In helium, the coherence of the 2s/2p He+ state is controlled by autoionizing states below the N = 2 threshold. This study investigates the impact of resonances below and above the N = 3 threshold on the coherence of the N = 3 He+ ion using the NEWSTOCK ab initio code, revealing the polarization of the ion at its inception through the dipole beating on a picosecond timescale.
Article
Optics
Andrej Mihelic, Martin Horvat
Summary: The theoretical method proposed in this study calculates multiphoton ionization amplitudes and cross sections for few-electron atoms. It extracts partial-wave amplitudes from a scattering wave function by solving driven Schrödinger equations, relying on a description of partial waves using a small number of Coulomb waves. The method is applicable for photon energies above and below ionization threshold and for resonance-enhanced multiphoton ionization.
Article
Mathematics, Applied
Federico Cacciafesta, Eric Sere, Junyong Zhang
Summary: In this paper, we prove uniform asymptotic estimates for confluent hypergeometric functions using the steepest-descent method. As an application, we obtain L-2-averaged Strichartz estimates over the angular direction for the massless Dirac-Coulomb equation in 3D.
COMMUNICATIONS IN PARTIAL DIFFERENTIAL EQUATIONS
(2023)
Article
Physics, Fluids & Plasmas
Francois Fillion-Gourdeau, Emmanuel Lorin, Steve MacLean
Summary: This article models the dynamics of low-energy electrons in general static strained graphene surface using the Dirac equation in curved space-time. Two strategies are introduced to simplify the problem: diagonal metric approximation and change of variables to isothermal coordinates. It is shown that electron wave packets can be focused by local strained regions on Gaussian shaped graphene surface deformations.
Article
Nanoscience & Nanotechnology
Wei Fu, Sha-Sha Ke, Ming-Xing Lu, Hai-Feng Lu
Summary: Research on the formation of bound states in tilted Dirac materials is important for understanding materials with Dirac cones. The study shows that tilting accelerates the process of atomic collapse, while overtilting leads to the disappearance of bound states.
PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES
(2021)
Article
Mathematics, Applied
Rosanna Campagna, Costanza Conti
Summary: This paper investigates two important analytical properties of hyperbolic polynomial penalized splines, HP-splines. The authors introduce HP-splines as a generalization of P splines, obtained by combining a special type of difference penalty with hyperbolic-polynomial B-splines (HB-splines). The study shows that these penalized splines can fit exponential data exactly and preserve the first and second 'exponential' moments.
APPLIED MATHEMATICS LETTERS
(2022)
Article
Mathematics, Applied
Rosanna Campagna, Costanza Conti
Summary: HP-splines are a special type of penalized splines that use hyperbolic-polynomial splines instead of polynomial splines, with a tailored discrete penalty term. They are more suitable for data with exponential trends.
APPLIED MATHEMATICS LETTERS
(2021)
Article
Mathematics, Applied
Xijia Liu, Hiba Nassar, Krzysztof Podgorski
Summary: This article presents a dyadic algorithm for diagonalizing an arbitrary positive definite band matrix, which is used to orthogonalize B-splines efficiently. The algorithm has two versions and can be applied to different types of Gramian matrices. By utilizing the sparsity of the band Gramian matrix, a natural orthogonal splinet network structure is obtained. Experimental results suggest that the method is more efficient than the theoretical bounds.
JOURNAL OF COMPUTATIONAL AND APPLIED MATHEMATICS
(2022)
Article
Mathematics, Applied
Rosanna Campagna, Costanza Conti, Salvatore Cuomo
Summary: In this work, a strategy for selecting the frequency parameter of hyperpolic-polynomial Psplines (HP-splines) is proposed. HP-splines are a type of hyperpolic-polynomial penalized splines that use exponential-polynomials and a tailored discrete penalty term. The strategy involves a linear algebra approach for Tikhonov regularization problems adapted to HP-splines, and numerical experiments show that it improves the trend capturing ability of HP-splines.
APPLIED MATHEMATICS AND COMPUTATION
(2023)
Article
Materials Science, Multidisciplinary
Hassen Dakhlaoui, Walid Belhadj, Bryan M. Wong
Summary: The transmission coefficient and electronic conductance of a graphene monolayer can be modulated by multi-electrostatic barriers, leading to a series of resonances depending on the number and widths of the barriers. These modifications in graphene hold potential for creating new optoelectronic devices, especially tunable field-effect transistors.
RESULTS IN PHYSICS
(2021)
Article
Computer Science, Interdisciplinary Applications
Usman Riaz, E. Seegyoung Seol, Robert Hager, Mark S. Shephard
Summary: The accurate representation and effective discretization of a problem domain into a mesh are crucial for achieving high-quality simulation results and computational efficiency. This work presents recent developments in extending an automated tokamak modeling and meshing infrastructure to better support the near flux field following meshing requirements of the XGC Gyro-kinetic Code.
COMPUTER PHYSICS COMMUNICATIONS
(2024)
Article
Computer Science, Interdisciplinary Applications
Zhenglu Li, Gabriel Antonius, Yang-Hao Chan, Steven G. Louie
Summary: This article presents a workflow for practical calculations of electron-phonon coupling and includes the effect of many-electron correlations using GW perturbation theory. The workflow combines different software packages to enable accurate calculations at the level of quasiparticle band structures.
COMPUTER PHYSICS COMMUNICATIONS
(2024)
Article
Computer Science, Interdisciplinary Applications
Akihiro Koide, Sara Rabouli, Pierre Le Meur, Sylvain Tricot, Philippe Schieffer, Didier Sebilleau, Calogero R. Natoli
Summary: We present the MsSpec Atomic Scattering Amplitude Package (MASAP), which includes a computation program and a graphical interface for generating atomic scattering amplitude (ASA). The study investigates the applicability of plane wave (PW) and curved spherical wave (SW) scattering in describing electron propagation. The results show that the imaginary part of the optical potential enhances the elastic scattering in the forward direction but causes damping effects in other directions.
COMPUTER PHYSICS COMMUNICATIONS
(2024)
Article
Computer Science, Interdisciplinary Applications
A. Bagci, Gustavo A. Aucar
Summary: The electron repulsion integrals over Slater-type orbitals with non-integer principal quantum numbers are investigated in this study. These integrals are important in calculations of many-electron systems. New relationships free from hyper-geometric functions are derived to simplify the calculations. With the use of auxiliary functions and straightforward recurrence relationships, these integrals can be efficiently computed, providing initial conditions for the evaluation of expectation values and potentials.
COMPUTER PHYSICS COMMUNICATIONS
(2024)
Article
Computer Science, Interdisciplinary Applications
Andrzej Daniluk
Summary: RHEED_DIFF_2D is an open-source software for qualitative numerical simulations of RHEED oscillation intensity changes with layer deposition, used for interpreting heteroepitaxial structures under different scattering crystal potential models.
COMPUTER PHYSICS COMMUNICATIONS
(2024)
Article
Computer Science, Interdisciplinary Applications
Niklas Kuehl, Hendrik Fischer, Michael Hinze, Thomas Rung
Summary: The article presents a strategy and algorithm for simulation-accompanying, incremental Singular Value Decomposition (SVD) for time-evolving, spatially parallel discrete data sets. The proposed method improves computational efficiency by introducing a bunch matrix, resulting in higher accuracy and practical applicability.
COMPUTER PHYSICS COMMUNICATIONS
(2024)
Article
Computer Science, Interdisciplinary Applications
Jose M. Rodriguez-Borbon, Xian Wang, Adrian P. Dieguez, Khaled Z. Ibrahim, Bryan M. Wong
Summary: This paper presents an open-source software package called TRAVOLTA for massively parallelized quantum optimal control calculations on GPUs. The TRAVOLTA package is an improvement on the previous NIC-CAGE algorithm and incorporates algorithmic improvements for faster convergence. Three different variants of GPU parallelization are examined to evaluate their performance in constructing optimal control fields in various quantum systems. The benchmarks show that the GPU-enhanced TRAVOLTA code produces the same results as previous CPU-based algorithms but with a speedup of more than ten times. The GPU enhancements and algorithmic improvements allow large quantum optimal control calculations to be efficiently executed on modern multi-core computational hardware.
COMPUTER PHYSICS COMMUNICATIONS
(2024)
Article
Computer Science, Interdisciplinary Applications
Weijie Hua
Summary: This work introduces a program called MCNOX for computing and analyzing ultrafast nonlinear X-ray spectra. It is designed for cutting-edge applications in photochemistry/photophysics enabled by X-ray free-electron lasers and high harmonic generation light sources. The program can calculate steady-state X-ray absorption spectroscopy and three types of ultrafast nonlinear X-ray spectra, and it is capable of identifying major electronic transitions and providing physical and chemical insights from complex signals.
COMPUTER PHYSICS COMMUNICATIONS
(2024)
Article
Computer Science, Interdisciplinary Applications
Leandro Benatto, Omar Mesquita, Lucimara S. Roman, Rodrigo B. Capaz, Graziani Candiotto, Marlus Koehler
Summary: Photoluminescence Quenching Simulator (PLQ-Sim) is a user-friendly software for studying the dynamics of photoexcited states at the interface between organic semiconductors. It provides important information on organic photovoltaic and photothermal devices and calculates transfer rates and quenching efficiency.
COMPUTER PHYSICS COMMUNICATIONS
(2024)
Article
Computer Science, Interdisciplinary Applications
Dongming Li, James Kestyn, Eric Polizzi
Summary: This study introduces a practical and efficient approach to calculate the all-electron full potential band structure in real space using a finite element basis. Instead of the k-space method, this method solves the Kohn-Sham equation self-consistently within a larger finite system enclosing the unit-cell. Non-self-consistent calculations are then performed in the Brillouin zone to obtain the band structure results, which are found to be in excellent agreement with the pseudopotential k-space method. Furthermore, the study successfully observes the band bending of core electrons.
COMPUTER PHYSICS COMMUNICATIONS
(2024)
Article
Computer Science, Interdisciplinary Applications
R. Kleiber, M. Borchardt, R. Hatzky, A. Koenies, H. Leyh, A. Mishchenko, J. Riemann, C. Slaby, J. M. Garcia-Regana, E. Sanchez, M. Cole
Summary: This paper describes the current state of the EUTERPE code, focusing on the implemented models and their numerical implementation. The code is capable of solving the multi-species electromagnetic gyrokinetic equations in a three-dimensional domain. It utilizes noise reduction techniques and grid resolution transformation for efficient computation. Additionally, various hybrid models are implemented for comparison and the study of plasma-particle interactions. The code is parallelized for high scalability on multiple CPUs.
COMPUTER PHYSICS COMMUNICATIONS
(2024)
Article
Computer Science, Interdisciplinary Applications
Pengliang Yang
Summary: This paper presents an open source software called SMIwiz, which combines seismic modelling, reverse time migration, and full waveform inversion into a unified computer implementation. SMIwiz supports both 2D and 3D simulations and provides various computational recipes for efficient calculation. Its independent processing and batchwise job scheduling ensure scalability, and its viability is demonstrated through applications on benchmark models.
COMPUTER PHYSICS COMMUNICATIONS
(2024)
Article
Computer Science, Interdisciplinary Applications
Christian Tantardini, Miroslav Ilias, Matteo Giantomassi, Alexander G. Kvashnin, Valeria Pershina, Xavier Gonze
Summary: Material discovery has been an active research field, and this study focuses on developing pseudopotentials for actinides and super-heavy elements. These pseudopotentials are crucial for accurate first-principles calculations and simulations.
COMPUTER PHYSICS COMMUNICATIONS
(2024)
Article
Computer Science, Interdisciplinary Applications
S. Blanes, F. Casas, C. Gonzalez, M. Thalhammer
Summary: This paper explores the extension of modified potential operator splitting methods to specific classes of nonlinear evolution equations. Numerical experiments confirm the advantages of the proposed fourth-order modified operator splitting method over traditional splitting methods in dealing with Gross-Pitaevskii systems.
COMPUTER PHYSICS COMMUNICATIONS
(2024)
Article
Computer Science, Interdisciplinary Applications
Siegfried Kaidisch, Thomas U. Hilger, Andreas Krassnigg, Wolfgang Lucha
Summary: Motivated by a use case in theoretical hadron physics, this paper revisits an application of a pole-sum fit to dressing functions of a confined quark propagator. Specifically, it investigates approaches to determine the number and positions of singularities closest to the origin for a function known numerically on a specific grid on the positive real axis. Comparing the efficiency of standard techniques to a pure artificial-neural-network approach and a combination of both, it finds that the combined approach is more efficient. This approach can be applied to similar situations where the positions of poles need to be estimated quickly and reliably from real-axis information alone.
COMPUTER PHYSICS COMMUNICATIONS
(2024)