Questions tagged [quantum-mechanics]

Numerical methods and problems involving the solution of the Schrodinger equation and related subatomic models.

Numerical methods and problems involving the solution of the Schrodinger equation.

128 questions
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Numerical Methods for the Schrodinger Equation

We are comparing the performance of various numerical methods that can be used to solve the Schrodinger's Equation for the Hydrogen Atom interacting with a strong laser pulse (too strong to use perturbation methods). When using discretization…
7
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How to numerically solve a laser driving semi-classical two-level system using Floquet formalism?

Consider the semi-classical laser driving two-level atom, where the laser is treated classically and the atom is treated quantum mechanically. The effect of laser on the atom is a dipole…
xslittlegrass
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Hamiltonian Matrix Size in Schrodinger Equation

I'm attempting to solve the particle-in-a-box problem using Scipy (with the help of http://www.physics.buffalo.edu/phy410-505/2011/topic4/app2/index.html). At first, I used a 16x16 matrix to model the Hamiltonian, like the link, and my results…
3
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1 answer

Numerical solution to the Landau-Zener problem

I tried to use a midpoint method and numerically solve the Schrödinger equation for the original Landau-Zener (LZ) problem: a $2\times 2$ Hamiltonian $$\left(\begin{array}{c} \alpha t\\ \delta \end{array}\begin{array}{c} \delta \\-\alpha t …
3
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2 answers

Solve numerically inwards and outwards the radial equation?

We have the Schrodinger eqn \begin{equation}(−\Delta+V(r))R(r)=E R(r)\end{equation} where we can take $V(r)=-k/r$ for the beginning and we impose on the reduced radial function $u(r)=r R(r)$ the boundary conditions $u(0)=u(\infty)=0$. The problem is…
wondering
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Split operator FFT quantum dynamics for a harmonic oscillator

I would like to do a numerical quantum dynamics of a displaced gaussian in harmonic oscillator using split-operator method (see bottom of these notes by Hal Evans for the algorithm). I have a problem with the step (3). I'm not sure how to represent…
2
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Numerov method for Schrodinger equation

While learning about numerical methods for solving the Schrödinger equation I came across Numerov's method. I want to get the solution for the harmonic oscillator by alreading giving the eigenvalues. The algorithm requires that I know two initial…
2
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1 answer

Monte Carlo normalization of a wave function

I would like to normalize a quantum mechanical multi-particle wave function numerically, and since the result is a multidimensional integral I thought Monte Carlo methods might be appropriate. So, I'm looking for $\mathcal{N}$…
jorgen
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Computing eigen-decomposition of several matrices in parallel in C++

I am writing a program in C++ in which I am trying to reduce the run-time by computing eigen-decomposition of several matrices in parallel. This might be a programming question but since many Physics people might use it, I am asking the question…
cleanplay
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Is it possible to eliminate the inner sum to evaluate numerically?

Any hints on how to simplify the following double sum to be able to find the sum at least numerically? $$\sum_{n=2}^{\infty}\frac1{n(n^2-1)} \sum_{k=1}^\infty \frac{(k-1/n)^{2n-2}}{(k+1/n)^{2n+2}}$$ Series comes from quantum mechanics (2nd order…
wondering
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How to get a Wannier function of tight-binding model numerically (i.e. Python)

I have a question on construction of a Wannier function for tight-binding model. Let's say we consider the tight-binding model of 1D chain with two atoms( site A and B in a unit cell). In k-space we can write the single-particle Hamiltonian in…