Wyniki wyszukiwania - BazTech

1

Infinitely many solutions for quasilinear Schrödinger equations with sign-changing nonlinearity without the aid of 4-superlinear at infinity

Khiddi Mustapha, Essafi Lakbir

Demonstratio Mathematica

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2022

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Vol. 55, nr 1

831--842

EN

In this article, we will prove the existence of infinitely many solutions for a class of quasilinear Schrödinger equations without assuming the 4-superlinear at infinity on the nonlinearity. We achieve our goal by using the Fountain theorem.

2

Computation of the ground state energy of the Schrödinger equation by a Monte Carlo method

Puchalski Adam

Mathematica Applicanda

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2021

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Vol. 49, no. 1

55--64

EN

The paper presents a new method of computing the ground state energy of the time-independent Schrödinger equation. The method is based on a local separation of variables: the Schrödinger equation is transformed to an equivalent system of local one-electron auxiliary equations which is used to derive an expression for the energy integral. The latter allows to calculate the ground-state energy of many-electron systems with the full inclusion of electron correlations. The multidimensional energy integrals are calculated using the Markov Chain Monte Carlo method. We provide benchmark results for two-electron systems which are in agreement with the accurate computations by the configuration interaction (CI) method.

PL

W pracy przedstawiono nową, niestandardową metodę obliczania energii stanu podstawowego w stacjonarnym równaniu Schrödingera. Metoda korzysta z lokalnego rozdzielenia zmiennych, które pozwala sprowadzić równanie Schrödingera dla układu wieloelektronowego do układu równań jedno-elektronowych i wyliczyć z nich całkę energii. Tak wyprowadzona całka energii pozwala obliczyć energię stanu podstawowego dla układów wielo-elektronowych z pełnym uwzględnieniem korelacji elektronów. Do obliczania wielo-wymiarowej całki energii wykorzystuje się algorytm Monte Carlo wykorzystujący łańcuchy Markowa. W pracy przedstawiono wyniki obliczeń dla układów dwu-elektronowych. Otrzymane wyniki porównano z obliczeniami uzyskanymi standardowo w obliczeniach kwantowych metodą oddziaływania konfiguracji (CI) uzyskując bardzo dobrą zgodność wyników przy znacznie mniejszej złożoności obliczeniowej.

3

Cubic nonlinear fractional Schrödinger equation with conformable derivative and its new travelling wave solutions

Gündoğdu Hami, Gözükızıl Ömer Faruk

Journal of Applied Mathematics and Computational Mechanics

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2021

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Vol. 20, nr 2

29--41

EN

In the present paper, the fractional-order cubic nonlinear Schrödinger equation is considered. The Schrödinger equation with time and space fractional derivative is studied at the same time. Different types of travelling wave solutions including the kink solution, soliton solution, periodic solution, and singular solution for the mentioned equation are obtained by using the Jacobi elliptic functions expansion method. It is shown that the solutions turn into the exact solutions when the fractional orders go to 1. This method can be relied on gaining the solutions to time or space fractional order partial differential equations as well as ordinary ones. Throughout this work, the fractional derivative is given in a conformable sense.

4

Quaternions and Cauchy Classical Theory of Elasticity

Danielewski Marek, Sapa Lucjan

Advances in Manufacturing Science and Technology

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2020

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Vol. 44, nr 2

67--70

EN

Developed by French mathematician Augustin-Louis Cauchy, the classical theory of elasticity is the starting point to show the value and the physical reality of quaternions. The classical balance equations for the isotropic, elastic crystal, demonstrate the usefulness of quaternions. The family of wave equations and the diffusion equation are a straightforward consequence of the quaternion representation of the Cauchy model of the elastic solid. Using the quaternion algebra, we present the derivation of the quaternion form of the multiple wave equations. The fundamental consequences of all derived equations and relations for physics, chemistry, and future prospects are presented.