Numerical solution of Schrodinger equation

In summary: If your algorithm is correct, then it should be able to find the eigenvalues and eigenfunctions for a simple potential such as the step potential. If you can't do this, then either your algorithm is incorrect or you are not using it correctly.In summary, the speaker is trying to numerically solve the Schrodinger equation for a specific problem and plot the solutions using a program like Mathematica. They are having trouble with the results, which may be wrong eigenfunctions. They are wondering why the program is giving divergent plots instead of finite ones, and if anyone has any ideas or suggestions for improvement. They also mention the Numerov method as a possible solution.
  • #1
arroy_0205
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Suppose for some specific problem (symmetric potential well) the Schroedinger equation is expected to give certain discrete bound states and corresponding eigenfunctions. Now I am trying to obtain the eigenfunctions by numerically solving the equation and plotting the solutions by randomly assigning energy value. In general most of the times my guess of energy value will be wrong but the program (say Mathematica) will give some result (plot for the wave function). What will be interpretation for those results?

The answer may be those are simply wrong eigenfunctions so no interpretation is needed. However I was doing this stupid job and was getting divergent wave functions almost always. But I do not understand why Mathematica was giving divergent plot rather than some arbitrary finite plot. Do you have any clue?
 
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  • #2
There is a solution (actually, two linearly independent solutions) of the time-indpendent Schrodinger equation in one dimension for every value of the energy. For bound states, these are only allowed if they are normalizable, and this only happens for certain precise values of the energy (and these are the energy eigenvalues).
 
  • #3
arroy_0205 said:
Suppose for some specific problem (symmetric potential well) the Schroedinger equation is expected to give certain discrete bound states and corresponding eigenfunctions. Now I am trying to obtain the eigenfunctions by numerically solving the equation and plotting the solutions by randomly assigning energy value. In general most of the times my guess of energy value will be wrong but the program (say Mathematica) will give some result (plot for the wave function). What will be interpretation for those results?

The answer may be those are simply wrong eigenfunctions so no interpretation is needed. However I was doing this stupid job and was getting divergent wave functions almost always. But I do not understand why Mathematica was giving divergent plot rather than some arbitrary finite plot. Do you have any clue?

I don't really understand what you are trying to ask. Have you written a program to calculate the eigenvalues and eigenfunctions or are you using someone else's program? The normal technique for numerically solving the 1-D Schrodinger Equation is the Numerov method, is your algorithm based on that technique? If not, you might want to google 'Numerov method' and look at the theory behind the method and maybe even some sample code and check it against your algorithm.
 

1. What is the Schrodinger equation?

The Schrodinger equation is a fundamental equation in quantum mechanics that describes the time evolution of a quantum system. It is a mathematical expression that relates the energy of a system to its wave function, which represents the probability of finding the system in a particular state.

2. Why is the Schrodinger equation important?

The Schrodinger equation is important because it allows us to make predictions about the behavior of quantum systems. It is used in many areas of physics, chemistry, and engineering to understand and manipulate the behavior of particles at the atomic and subatomic level.

3. What is the numerical solution of the Schrodinger equation?

The numerical solution of the Schrodinger equation involves using computational methods to solve the equation and obtain a numerical approximation of the wave function. This allows us to study the behavior of quantum systems that cannot be solved analytically.

4. How is the Schrodinger equation solved numerically?

The Schrodinger equation is typically solved numerically using algorithms such as the finite difference method, the finite element method, or the variational method. These methods discretize the wave function and energy values and use iterative calculations to find the most accurate approximation.

5. What are the limitations of numerical solutions of the Schrodinger equation?

One limitation of numerical solutions of the Schrodinger equation is that they can only provide approximate solutions, rather than exact solutions. Additionally, the accuracy of the solution is dependent on the chosen numerical method and the size of the computational grid used. In some cases, it may also be computationally intensive to solve the equation for complex systems.

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