Wavelet Method in Numerical Modeling of Quantum Dots Embedded in Matrix

2013 ◽  
Vol 849 ◽  
pp. 427-434 ◽  
Author(s):  
Aleksander Muc ◽  
Aleksander Banaś

An analytical method of the solution of the governing nonlinear eigenproblem is proposed. It can be directly applied into the analysis of eigenstates in quantum mechanics. The method is based on the use of the separation of variables for specific shapes of quantum dots. In this way the analysis can be reduced to the disretization along one variable only the Daubechies wavelets. The eigenstates are derived with the use of the variational formulation combined with the method of the Rayleigh quotient

2020 ◽  
Vol 0 (4) ◽  
pp. 29-32
Author(s):  
B.M. GAREEV ◽  
◽  
A.M. ABDRAKHMANOV ◽  
G.L. SHARIPOV ◽  
◽  
...  

The photoluminescence of carbon quantum dots synthesized from natural honey and mixtures of honey and sugar has been studied. An increase in the sugar content leads to a decrease in the photoluminescence intensity without changing the shape of the luminescence spectrum of these quantum dots aqueous solutions, which is associated with a decrease in the yield of their synthesis in the sugar presence. The discovered effect can be used to detect sugar in honey. When examining five different market samples of flower honey using this method, two of them showed a significant decrease in the photoluminescence intensity. A laboratory test for compliance with GOST 19792-2017 Standard requirements established an excess of the sucrose content in these samples. Luminescent determination of sugar in honey does not require complicated equipment and can be used to develop a new analytical method for determining the sugar content in counterfeit natural honey.


2012 ◽  
Vol 24 (4-6) ◽  
pp. 377-390 ◽  
Author(s):  
B. E. Abali ◽  
C. Völlmecke ◽  
B. Woodward ◽  
M. Kashtalyan ◽  
I. Guz ◽  
...  

2020 ◽  
Vol 142 (9) ◽  
Author(s):  
Yingze Jin ◽  
Xiaoyang Yuan

Abstract To improve the efficiency in nonlinear dynamic calculation of finite-length tilting-pad journal bearings (TPJBs) under dynamic loads, an analytical method for hydrodynamic bearing forces, which considers the turbulence effect, is proposed using the method of separation of variables under the dynamic Gümbel boundary condition. No thermal effects are considered because this method is designed for the low viscosity case. The infinitely long bearing pressure is introduced as the circumferential pressure, and a general solution of the nonhomogeneous Reynolds equation is derived as the axial pressure. The turbulence model of Ng and Pan is characterized by a linear function of film thicknesses. A complete analytical expression of hydrodynamic bearing forces is derived. The analytical simulation shows slight differences and extremely low time expense in lubricating and dynamic performance compared to published data and finite difference method (FDM) simulation. The analytical method could be used to fast evaluate the nonlinear dynamic performance of a TPJB-rotor system in the low viscosity environment, supporting the nonlinear dynamic design of the system.


2012 ◽  
Vol 2012 ◽  
pp. 1-25 ◽  
Author(s):  
Yidu Yang ◽  
Yu Zhang ◽  
Hai Bi

This paper discusses highly finite element algorithms for the eigenvalue problem of electric field. Combining the mixed finite element method with the Rayleigh quotient iteration method, a new multi-grid discretization scheme and an adaptive algorithm are proposed and applied to the eigenvalue problem of electric field. Theoretical analysis and numerical results show that the computational schemes established in the paper have high efficiency.


Respuestas ◽  
2017 ◽  
Vol 22 (1) ◽  
pp. 29
Author(s):  
Cristian Andrés Aguirre-Téllez ◽  
José Barba-Ortega

El problema general en mecánica cuántica está basado en la solución de una ecuación en valores propios de un operador dado (en una representación adecuada), generalmente  dicho operador es el Hamiltoniano que da cuenta de la interacción energética (salvo que dependa del tiempo) del sistema en cuestión. La solución de la ecuación de Schrödinger permite escribir el comportamiento dinámico del sistema sometido a ciertas restricciones. Sin embargo, la solución analítica de esta ecuación es viable solo en sistemas simples, cuando el sistema se describe desde la interacción de muchas partículas (problema electrónico-base de la construcción de sistemas cuánticos complejos aplicable a la descripción de moléculas, sólidos y sistemas cuánticos interactuantes en general.) la solución de la ecuación de Schrödinger del sistema no se puede realizar vía método analítico; con lo cual existe una forma más global de enfrentar dicho problema, el método auto consistente; mediante el cual se puede solucionar sistemas complejos de muchos cuerpos. Es así que en el presente paper presentamos una comparación entre el sistema auto consistente y algunas variantes que existen, con el método analítico en sistemas demuchos cuerpos y como opera dicho método, esto aplicado a un problema de dos cuerpos con interacción Coulombiana, ya que este problema presenta solución analítica y ha sido extensamente estudiado; esto con la finalidad de que los estudiantes interesados en la materia comprendan como se abordan problemas vía métodos auto consistentes y como opera este método, ya que en la literatura pocas veces se presenta el algoritmo de solución mediante este método.Palabras clave: Mecánica Cuántica, Método Auto-Consistente, problema de dos cuerpos.AbstractThe general problem in quantum mechanics is based on the solution of an equation in eigenvalues of a given operator (in a suitable representation), generally said operator is the Hamiltonian that accounts for the energy interaction (unless it depends on the time) of the system in question. The solution of the Schrodinger equation allows writing the dynamic behavior of the system subject to certain restrictions. however, the analytical solution of this equation is feasible only in simple systems, when the system is described from the interaction of many particles (electronic problem- basis of the construction of complex quantum systems applicable to the description of molecules, solids and interacting quantum systems in general.), the solution of the Schrödinger equation of the system can´t be performed via analytical method; with which there is a more global way of facing this problem, the self-consistent method; through which complex systems of many bodies can be solved. thus, in the present paper we present a comparison between the self-consistent system and some variants that exist, with the analytical method in systems of many bodies and how this method operates, this applied to a problem of two bodies with Coulombian interaction, since this problem presents an analytical solution and has been extensively studied; this in order that students interested in the subject understand how problems are addressed through self-consistent methods and how this method operates, since in the literature rarely the solution algorithm is presented by this method.Keywords: Quantum mechanics, Self Consistent Field, Two body problem.


2018 ◽  
Vol 40 ◽  
pp. 58
Author(s):  
Fabio Silva Botelho

This article develops a variational formulation for  relativistic quantum mechanics. The main results are obtained through a connection between relativistic and quantum mechanics. Such a connection is established through basic concepts on Riemannian geometry and related extensions for the relativistic context.


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