# Search results

1. ### A TD perturbation - state initially in continuous part

Hi everyone, I am doing a time dependent perturbation theory, in a case when the electron is prepared in a state of the continuous part of the energy spectrum. Existence of the discrete part and the degeneracy of the continuous part is irrelevant at the moment and will not be considered...
2. ### A Numerical solution to SE - variational method, many electrons

Hi everyone, I am trying to find electron wavefunction of a system I am working in. Numerical method I choose is the Variational method (VM). This method is convenient to find the ground state of the system. More details are available here. Problem I have can be explained on a very simple...
3. ### A Transition dipole moment - polarized absorption

Hi everyone, I am interested how is polarized light absorbed by a molecule or an atom. Unfortunately, I come to a problem in the derivation where a complex vector in a real space appears. This is something I never seen before and I do not know how to interpret it. Therefore I would like to ask...
4. ### Rashba effect due to the external electric field

Hi, I am modeling structure that takes into account Rashba effect, and I am not sure what is the mechanism that causes Rashba effect to appear. On wikipedia Rashba is described as spin-orbit interaction effect which appears because electron is orbiting around nucleus and electron see nucleus...
5. ### Particle in magnetic field, classical and quantum view

Hi, I am trying to understand quantum description of electron in B field. What I am looking for is how to relate quantum and classical view? If in classical treatment electron comes in homogeneous B field, it will go in circular motion around magnetic field lines, with radius R. From...
6. ### Precession in B field

There is a problem about precession in general that I am trying to understand, and it can be exampled by electron orbiting around nucleus in external \vec{B} field. We could consider electron motion as loop current which is characterized by the magnetic moment \vec{μ}...
7. ### Time as non-fundamental physical quantity

I have a little confusion in my head when I want to imagine time. Time is a bit more abstract then space dimensions for me. So I began from definition of time, and it is defined through motion of electrons in Cs atom. Therefore, I thought if the Universe was so simple, such that there are only...
8. ### Bound state wave function

Hi :), recently I was thinking whether every bound state is only real or imaginary, not mixture? Since all bound states have degeneracy of level one, if we suppose that ψ=ψ_{r}+iψ_{i}, then ψ_{r} and ψ_{i} must be linearly dependent as in opposite case there would be a bound state with...
9. ### Finite difference method for even potential in QM

Hello to everyone, while solving homework course Nanotechnology and Nanocomponents, I have encountered a problem in FD method that is applied in even potential. In my homework assignment it is explicitly said that it must be done only in x>0 part of the domain, where my problem starts with...
10. ### Introduction to Gross-Pitaevskii equation

Hi to everyone :) Like the topic's title says, I am starting my journey to Bose-Einstein condensate. What I am looking for are some basic introductory papers or materials that deal with derivation of the Gross-Pitaevskii equation on the basic, most elementary level that is possible. I am...
11. ### Double barrier potential in electrical field with matlab

Hello there :), I have a problem in calculating transmission probability through double barrier potential in electrical field with matlab. While doing some exercises form http://www.nextnano.de/nextnano3/tutorial/1Dtutorial_Transmission_NEGF.htm, I came to the last one, where external field is...
12. ### Mathematics needed for string theory

Hello, like I said in the topic title I am interested in what mathematics is needed for string theory to be studied. I am in faculty of electrical engineering, sub-filed nanoelectronics. I have good knowledge of math but not good in comparison with what is needed for superstrings, which I...
13. ### What is the meaning of k in E(k) diagram?

hello :) , like I said in the title of this topic I am confused about physical interpretation of physical quantity ˝k˝. I came to this problem while doing the first chapter of book in semiconductor physics, where authors simply define some value (parameter) ˝k˝ thanks to solution of some...
14. ### Resonant tunneling diode

Hello :) , Does anyone know some good paper or book from were it's possible to learn physics behind of work of resonant tunneling diode(RTD)? In last semester I had course in ˝microelectronics and nanoelectronics˝ and we studied basic principle on which RTD works, and it was very interesting...
15. ### Diffraction and interference

Hello, could someone tell me what is the main difference between effects of diffraction and interference? For now, I think that diffraction is name for deviation of waves when they come to obstacle. And interference is phenomenon when two or more waves are in superposition in some point...
16. ### Two curves in a cut point would have a same tangent

Ola, If we have two curves, and they cut them selves in a way like these two: y=x^2 and x^2+(y-1)^2=1. Does it always mean that those two curves in a cut point would have a same tangent, in other words do they need to have the same derivative in that spot? Thanks!!
17. ### Linear Harmonic Oscillator

Hello there, Can anyone help me, I am struggling with solving LHO in two dimension,but in the polar coordinates. I transfer laplacian into polar from decart coordinates, write Ψ=ΦR, and do fourier separation method for solving differential equation. But I do not know how to solve...