Trial function and Eigenfunction....

In summary, the conversation discusses how to determine if a trial function is an eigenfunction of a Hamiltonian by comparing its corresponding expectation value of energy to the eigenvalues of the Hamiltonian. If the values are not exactly the same, the trial function is not an eigenfunction.
  • #1
Ronf
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Homework Statement


Hello, I just started to study QM, I just have a general question, how to know if a trial function is not an eigenfunction of a hamiltonian (that has the lowest value in a graph) ? - Thanks and sorry for the stupid question.

Homework Equations

The Attempt at a Solution


I have an idea, but I am not sure if it is right. Is the trial function a eigenfuction of a hamiltonian, if it gives a value (lowest) which is very close to the ground-state energy? [/B]
 

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  • #2
Ronf said:
how to know if a trial function is not an eigenfunction of a hamiltonian (that has the lowest value in a graph) ?
It is not when the corresponding expectation value of energy does not match any of the eignvalues of the Hamiltonian.
Ronf said:
Is the trial function a eigenfuction of a hamiltonian, if it gives a value (lowest) which is very close to the ground-state energy?
Again, if this value is not exactly the same as one of the Hamiltonian's eigenvalues, then the tried function is not an eigenfunction.
 
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Likes Ronf
  • #3
Thank you man, I really appreciate your help, much love to you. :smile:
 

1. What is a trial function?

A trial function is a mathematical function used in the method of variation of parameters to find an approximate solution to a differential equation. It is typically chosen to have a similar form to the unknown solution, making it easier to determine the parameters that will lead to the best approximation.

2. What is an eigenfunction?

An eigenfunction is a special type of function that, when multiplied by a constant, returns itself as a result. In other words, it is a function that is only changed by a scaling factor. These functions are commonly used in physics and engineering to describe the behavior of systems.

3. How does a trial function relate to an eigenfunction?

A trial function can be thought of as an approximation of an eigenfunction. By using a trial function, we are trying to find the best possible approximation to the true eigenfunction. This allows us to easily calculate the parameters needed for the approximation, which can then be used to find the eigenfunction itself.

4. Can a trial function always be used to find an eigenfunction?

No, a trial function may not always lead to an eigenfunction. It is possible that the trial function chosen is not a good approximation of the true eigenfunction, or that the parameters chosen do not lead to an eigenfunction. In these cases, a different approach may be needed to find the eigenfunction.

5. What are some common examples of eigenfunctions?

Some common examples of eigenfunctions include trigonometric functions, exponential functions, and Bessel functions. These types of functions often arise in physics and engineering problems involving systems that have a special type of symmetry or periodic behavior.

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