Eigenvalue problem with operators as matrix elements

Click For Summary
SUMMARY

The discussion focuses on solving an eigenvalue problem represented by a matrix involving partial derivatives and a function u(x). The matrix is defined as follows: \begin{bmatrix} \partial_x^2 + \mu + u(x) & u(x)^2 \\ \bar{u(x)}^2 & \partial_x^2 + \mu + u(x) \end{bmatrix}. The goal is to determine the eigenfrequency ω(x) and the corresponding eigenvectors a(x) and b(x). Participants clarify that ω should not depend on x and emphasize the importance of specifying whether the derivative notation indicates a partial or directional derivative.

PREREQUISITES
  • Understanding of eigenvalue problems in linear algebra
  • Familiarity with matrix operations and eigenvectors
  • Knowledge of partial derivatives in the context of physics
  • Basic comprehension of functions and their properties, particularly u(x)
NEXT STEPS
  • Study the method of solving eigenvalue problems in quantum mechanics
  • Learn about the implications of matrix representations in differential equations
  • Explore the role of boundary conditions in determining eigenvalues and eigenvectors
  • Investigate the relationship between eigenvalues and stability in physical systems
USEFUL FOR

Mathematicians, physicists, and engineers working on eigenvalue problems, particularly those involving differential equations and matrix representations in one-dimensional systems.

wil3
Messages
177
Reaction score
1
Hello, I have a feeling that the solution to this question is going to be incredibly obvious, so my apologies if this turns out to be really dumb. How do I solve the following eigenvalue problem:

<br /> <br /> \begin{bmatrix}<br /> \partial_x^2 + \mu + u(x) &amp; u(x)^2 \\<br /> \bar{u(x)}^2 &amp; \partial_x^2 + \mu + u(x)<br /> \end{bmatrix}<br /> \begin{bmatrix}<br /> a(x)\\<br /> b(x)<br /> \end{bmatrix}<br /> =<br /> \omega(x)<br /> \begin{bmatrix}<br /> a(x)\\<br /> b(x)<br /> \end{bmatrix}<br />

where all x dependencies have been declared. I know the definition of the function u(x), but I need to solve for the eigenfrequency and eigenvectors.
 
Physics news on Phys.org
wil3 said:
Hello, I have a feeling that the solution to this question is going to be incredibly obvious, so my apologies if this turns out to be really dumb. How do I solve the following eigenvalue problem:

<br /> <br /> \begin{bmatrix}<br /> \partial_x^2 + \mu + u(x) &amp; u(x)^2 \\<br /> \bar{u(x)}^2 &amp; \partial_x^2 + \mu + u(x)<br /> \end{bmatrix}<br /> \begin{bmatrix}<br /> a(x)\\<br /> b(x)<br /> \end{bmatrix}<br /> =<br /> \omega(x)<br /> \begin{bmatrix}<br /> a(x)\\<br /> b(x)<br /> \end{bmatrix}<br />

where all x dependencies have been declared. I know the definition of the function u(x), but I need to solve for the eigenfrequency and eigenvectors.
I assume that you mean to find the function omega of x? You need to specify, because it's unclear what you want. Is your use of del indicating a partial derivative or a directional derivative. Be specific.
 
Typo in question: \omega should not depend on x. I want to solve for \omega, hence why I am calling this an eigenvalue problem. I'm not sure if getting w will also give a and b, like in a standard linear system.

\partial_x indicates a partial derivative, which is standard notation in physics for this sort of problem. But the problem would be identical if you wanted to interpret that as a directional derivative (both because the problem is one dimensional and because the subscript x would suggest a derivative in the x direction).
 

Similar threads

  • · Replies 2 ·
Replies
2
Views
4K
  • · Replies 4 ·
Replies
4
Views
3K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 4 ·
Replies
4
Views
3K
  • · Replies 33 ·
2
Replies
33
Views
2K
  • · Replies 0 ·
Replies
0
Views
3K
  • · Replies 17 ·
Replies
17
Views
4K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 7 ·
Replies
7
Views
3K
  • · Replies 1 ·
Replies
1
Views
4K