Article
Mathematics, Applied
Ihsan Lateef Saeed, Mohammad Javidi, Mahdi Saedshoar Heris
Summary: This paper investigates the numerical solution of the Riesz space fractional advection-dispersion equation. The Riesz fractional derivative is approximated using spline interpolation for the space variable, and two difference schemes are obtained by approximating the time ordinary derivative using Euler and Crank-Nicolson methods. The stability of the two schemes is proved using matrix analysis, and numerical results show their effectiveness.
COMPUTATIONAL & APPLIED MATHEMATICS
(2022)
Article
Mathematics, Interdisciplinary Applications
Dimiter Prodanov
Summary: This study demonstrates the connections between stochastic mechanics, scale relativity theory, and various equations, revealing their relationships through complex mathematical models and derivations.
CHAOS SOLITONS & FRACTALS
(2021)
Article
Mathematics, Interdisciplinary Applications
Dimiter Prodanov
Summary: This paper explores the connections between Burgers, diffusion, Schrodinger's and Klein-Gordon's equations by examining the relationship between stochastic mechanics and scale relativity theory. The main achievement of the article is the transparent derivation of the Born rule from a complex stochastic process.
CHAOS SOLITONS & FRACTALS
(2021)
Article
Mathematics, Applied
Yvonne Alama Bronsard
Summary: We analyze a class of time discretizations for solving the nonlinear Schrodinger equation with non-smooth potential and at low-regularity on an arbitrary Lipschitz domain omega subset of R-d, d <= 3. We provide convergence results under lower regularity assumptions than classical methods and demonstrate first and second order convergence in the case of periodic boundary conditions through numerical experiments.
JOURNAL OF COMPUTATIONAL AND APPLIED MATHEMATICS
(2023)
Article
Mathematics, Applied
Xavier Antoine, Jeremie Gaidamour, Emmanuel Lorin
Summary: This paper is interested in computing the ground state of nonlinear Schrodinger/Gross-Pitaevskii equations using gradient flow type methods. The authors derived and analyzed Fractional Normalized Gradient Flow methods, which involve fractional derivatives and generalize the well-known Normalized Gradient Flow method proposed by Bao and Du in 2004. Several experiments are proposed to illustrate the convergence properties of the developed algorithms.
COMMUNICATIONS IN NONLINEAR SCIENCE AND NUMERICAL SIMULATION
(2024)
Article
Mathematics, Applied
Mark J. Ablowitz, Justin T. Cole, Igor Rumanov
Summary: In this paper, Whitham modulation equations are derived to study the properties of the nonlinear Schrodinger equation with small dispersion in the plane. The modulation equations are obtained in terms of physical and Riemann-type variables, which can be used to describe hydrodynamic phenomena. By applying this method, the linear stability of one-dimensional traveling waves is determined, and it is found that the waves are unstable in both elliptic and hyperbolic cases. This result is consistent with previous investigations using other methods and is supported by direct numerical calculations.
STUDIES IN APPLIED MATHEMATICS
(2023)
Article
Mathematics, Applied
A. Abdi, J-P Berrut, S. A. Hosseini
Summary: This paper presents highly accurate explicit methods based on the Floater-Hormann family of linear barycentric rational interpolants for solving Volterra integral equations and non-stiff problems. The order of convergence and linear stability properties are analyzed, and numerical experiments are conducted to validate the theoretical results.
APPLIED NUMERICAL MATHEMATICS
(2022)
Article
Mathematics, Applied
M. -Y. Nour, A. Lamnii, A. Zidna, D. Barrera
Summary: A construction of Marsden's identity for UE-splines is developed and a complete proof is given. With the help of this identity, a new non-uniform quasi-interpolant that reproduces the spaces of polynomial, trigonometric and hyperbolic functions are defined. Efficient quadrature rules based on integrating these quasi-interpolation schemes are derived and analyzed. Then, a quadrature formula associated with non-uniform quasi-interpolation along with Nystrom's method is used to numerically solve Hammerstein and Fredholm integral equations. Numerical results that illustrate the effectiveness of these rules are presented.
APPLIED NUMERICAL MATHEMATICS
(2023)
Article
Engineering, Mechanical
Yuexing Bai, Temuer Chaolu, Sudao Bilige
Summary: This paper introduces an improved deep learning method for recovering the new soliton solution of the Huxley equation, showing that the improved algorithm can reconstruct the exact solution with faster convergence speed and better simulation effect compared to traditional methods.
NONLINEAR DYNAMICS
(2021)
Article
Mathematics, Interdisciplinary Applications
Sri Sulasteri, Mawardi Bahri, Nasrullah Bachtiar, Jeffry Kusuma, Agustinus Ribal
Summary: The main objective of this study is to find the solution of the generalized heat and generalized Laplace equations using the fractional Fourier transform, which is a general form of the solution of these equations using the classical Fourier transform. The solution is also formulated using a sampling formula related to the fractional Fourier transform. The study introduces the fractional Fourier transform, collects related theorems and essential properties, and derives several results related to the sampling formula. Several examples are presented to demonstrate the effectiveness and powerfulness of the proposed method compared to the classical Fourier transform method.
FRACTAL AND FRACTIONAL
(2023)
Article
Mathematics, Applied
Mary Nanfuka, Fredrik Berntsson, John Mango
Summary: The study regularizes the Cauchy problem for the Helmholtz equation by introducing Cubic smoothing splines to approximate the second derivative, leading to stability estimates and accurate numerical results.
JOURNAL OF APPLIED MATHEMATICS AND COMPUTING
(2022)
Article
Mechanics
Gennady A. El
Summary: This study reviews the spectral theory of soliton gases in integrable dispersive hydrodynamic systems by presenting both a phenomenological approach based on phase shifts in pairwise soliton collisions and a more detailed theory modeling soliton gas dynamics by a thermodynamic limit of modulated finite-gap spectral solutions of the Korteweg-de Vries and focusing NLS equations. The integrability properties of the kinetic equation for soliton gas are discussed, and physically relevant solutions are compared with direct numerical simulations of dispersive hydrodynamic systems.
JOURNAL OF STATISTICAL MECHANICS-THEORY AND EXPERIMENT
(2021)
Article
Mathematics
Ming Wang, Ze Li, Shanlin Huang
Summary: In this paper, unique continuation inequalities for nonlinear Schrodinger equations on R-d are proved at two different moments in time. The results show that if the solution is small at two different times outside a ball, then it is small in the whole space. The main tools used in the proof are uncertainty principles in harmonic analysis.
INDIANA UNIVERSITY MATHEMATICS JOURNAL
(2023)
Article
Mathematics
Vikash Kumar Sinha, Prashanth Maroju
Summary: In this paper, a new variational iteration method using the quasilinearization method and Adomian polynomial is developed to solve nonlinear differential equations. The convergence analysis of the method is discussed under the Lipschitz continuity condition in Banach space. Several application problems are included to test the efficacy of the proposed method. The method's behavior is investigated for different values of parameter t. This technique is a powerful tool for solving a wide range of nonlinear problems.
Article
Geochemistry & Geophysics
Ya-Juan Xue, Xing-Jian Wang, Jun-Xing Cao, Hao-Kun Du, Jian-Yong Xie, Jia-Chun You, Xu-Dong Jiang, Jia Yang
Summary: We propose a stable seismic Q estimation approach based on quantum mechanics by projecting seismic traces onto a specific basis and deriving a quantum mechanics-based Q estimation method in the local frequency-projection coefficient domain. Compared with traditional methods, this approach shows more stability and noise robustness.
IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING
(2022)
Article
Chemistry, Physical
Robert Wodraszka, Tucker Carrington
JOURNAL OF CHEMICAL PHYSICS
(2020)
Article
Chemistry, Physical
Xiao-Gang Wang, Tucker Carrington
JOURNAL OF CHEMICAL PHYSICS
(2020)
Review
Chemistry, Multidisciplinary
Sergei Manzhos, Tucker Carrington
Summary: This review focuses on the development of neural network-based methods for constructing molecular potential energy surfaces that explicitly include all many-body contributions. Various approaches including single NN PES fitting and more complex methods are discussed, highlighting the effectiveness of NNs in building representations with low-dimensional functions and emerging tools for accurate PESs in relatively large molecular systems.
Review
Spectroscopy
Tucker Carrington
Summary: In this paper, collocation methods for solving the time-independent and the time-dependent Schroedinger equation are reviewed. Compared to traditional variational methods, collocation methods do not require integrals and quadrature, unless the potential does not have a special form. There are established ideas for reducing the size of the basis in a variational calculation, but difficulties with quadrature still arise.
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
(2021)
Article
Chemistry, Physical
Xiao-Gang Wang, Tucker Carrington
Summary: Highly converged energy levels and wavefunctions of the methane-water van der Waals complex are obtained using Wigner D basis functions and the Symmetry-Adapted Lanczos (SAL) method. The SAL method reduces computation cost and allows for the efficient labeling of energy levels based on symmetry, without explicitly using symmetry-adapted basis functions. Unusually strong transitions between states associated with the isomers of the global minimum and the secondary minimum are identified, along with the computation of line strengths and discovery of new bands.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Chemistry, Physical
Robert Wodraszka, Tucker Carrington
Summary: The rectangular collocation MCTDH (RC-MCTDH) method simplifies the use of time-independent collocation points, making it easier to evaluate the potential energy function and reduce errors. In contrast, when using a discrete variable representation, the only way to reduce quadrature errors is to increase the basis size.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Chemistry, Physical
Jesse Simmons, Tucker Carrington
Summary: By using collocation and a SOP PES to compute solutions on a general PES, it is possible to improve computational accuracy and reduce differences in energy levels by approximately two orders of magnitude.
CHEMICAL PHYSICS LETTERS
(2021)
Article
Chemistry, Physical
Sangeeth Das Kallullathil, Tucker Carrington
Summary: This paper discusses a method that uses the canonical polyadic (CP) format to compute vibrational energy levels of polyatomic molecules by constructing a basis from vectors obtained by solving linear equations. The approach eliminates the need to generate tensors with a rank higher than the fixed rank used to solve the linear equations, without requiring rank reduction or orthogonalization.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Physics, Atomic, Molecular & Chemical
Dominika Viglaskan, Xiao-Gang Wang, Tucker Carrington, David P. Tew
Summary: In this paper, rovibrational energy levels, transition frequencies, and intensities for H2O-HF were computed using a new ab initio potential energy surface and compared with experimental data. Better agreement with experiment was obtained on the new potential by re-assigning the R(1) transitions of two vibrational states. The study demonstrated the importance of using a precise potential energy surface for accurate rovibrational calculations and comparisons with experimental data.
JOURNAL OF MOLECULAR SPECTROSCOPY
(2022)
Article
Chemistry, Physical
Xiao-Gang Wang, Tucker Carrington Jr
Summary: Due to the ubiquity and importance of water, water dimer has been extensively studied. Despite the challenges of computing the (ro-)vibrational spectrum of water dimer, a variational approach using a product contracted basis is used in this study. The full G(16) symmetry of water dimer is exploited, and the results are compared with experimental data. The study reveals surprising findings regarding tunneling splittings and vibrational shifts, and differences with previous approaches.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Jesse Simmons, Tucker Carrington
Summary: We propose a new collocation method for calculating the vibrational spectrum of a polyatomic molecule. By introducing more points than basis functions, our method achieves better accuracy, thus making it compatible with large bases. This method overcomes the previous limitation of incompatibility with iterative eigensolvers. Our tests on molecules with up to six atoms show that even with non-optimal equally spaced points, accurate energy levels can be obtained.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Sangeeth Das Kallullathil, Tucker Carrington Jr
Summary: In this paper, the authors propose the use of the CP-MSBII eigensolver and a contraction tree to calculate vibrational spectra. The CP-MSBII eigensolver utilizes the CP format, which has a linear memory cost with respect to the number of coordinates. By breaking down the full problem into smaller sub-problems and using a contraction tree, the required rank for each sub-problem becomes small. The authors demonstrate the effectiveness of their approach by computing the vibrational energy levels of acetonitrile and ethylene oxide.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Review
Chemistry, Physical
Sergei Manzhos, Manabu Ihara, Tucker Carrington
Summary: This article reviews the collocation approach to solving the Schro''dinger equation and its applications. It discusses the interrelations between collocation and other methods, while highlighting the advantages and disadvantages of the rectangular collocation formulation. The use of collocation allows for the use of optimized coordinates and basis functions, including nonintegrable basis functions, and provides a straightforward way of handling singularities in the potential. It also facilitates tuning the shape of basis functions and the placement of points with machine-learning methods. Applications to electronic and vibrational problems, particularly for molecule-surface systems where potential energy surfaces are unavailable, are discussed.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2023)
Article
Physics, Atomic, Molecular & Chemical
Nuoyan Yang, Spencer Hill, Sergei Manzhos, Tucker Carrington
Summary: In order to compute a vibrational spectrum, one often starts with ab initio Born-Oppenheimer potential values at fitting points and uses interpolation or fitting to find values at quadrature or collocation points. Gaussian Process (GP) is commonly used to build a potential energy surface (PES). Using local GP fits instead of a global fit reduces computational cost significantly while still providing accurate energy levels. This local approach allows for accurate calculations with a reduced number of fitting points and matrix inversion.
JOURNAL OF MOLECULAR SPECTROSCOPY
(2023)
Review
Chemistry, Physical
Sergei Manzhos, Manabu Ihara, Tucker Carrington
Summary: This paper reviews the collocation approach for solving the Schro''dinger equation and its applications, emphasizing the interrelations with other methods. The advantages and disadvantages of the rectangular collocation formulation are also discussed. Collocation allows for the use of any coordinates and basis functions, including nonintegrable ones, and provides a straightforward way to handle singularities in the potential. Additionally, collocation facilitates tuning the shape of basis functions and the placement of points, which can be done using machine-learning methods. The paper focuses on applications to electronic and vibrational problems, particularly calculations for molecules on surfaces where variational calculations are limited. Collocation has advantages in cases where potential energy surfaces are unavailable, such as molecule-surface systems, and in systems where standard direct product quadrature grids used with variational methods are expensive.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2023)