Eigenfunctions and eigenvalues of Fourier Transform?

In summary, the conversation discusses the Hermite Polynomials as Eigenfunctions of the Fourier transform with Eigenvalues i^{n} and i^{-n}. This refers to the property that the Fourier transform of the nth Hermite Polynomial, Hn, is inHn. The conversation also mentions the definition of eigenvalues and eigenvectors in linear algebra and how they relate to the Fourier transform. Finally, there is a note regarding a typo in the equation.
  • #1
eljose
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:rolleyes: :cool: I have a question..yesterday at Wikipedia i heard about the "Hermite Polynomials2 as Eigenfunctions of Fourier (complex?) transform with Eigenvalues i^{n} and i^{-n}...could someone explain what it refers with that?...when it says "Eigenfunctions-values" it refers to the Kernel K(x,t) that is a complex exponential function?...
 
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  • #2
In Linear Algebra, an "eigenvalue" and "eigenvector" of a linear transformation, L, are a number, [itex]\lambda[/itex], and vector, v, such that [itex]Av= \lambda v[/itex]. We can think of the set of (integrable) functions as a vector space and the Fourier transform is a linear transformation on that set. The Hermite Polynomials have the property that the Fourier transform of the nth Hermite Polynomial, Hn, is
F(Hn)= inHn.
 
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  • #3
Note to Halls of Ivy. You left out the eigenvalue in your definition equation.
 
  • #4
mathman said:
Note to Halls of Ivy. You left out the eigenvalue in your definition equation.
Thanks, I've edited it.
 
  • #5
mathman said:
Note to Halls of Ivy. You left out the eigenvalue in your definition equation.
Thanks, I've edited it. (I misspelled "lamba" in the TEX)
 

FAQ: Eigenfunctions and eigenvalues of Fourier Transform?

What is a Fourier Transform?

A Fourier Transform is a mathematical operation that decomposes a function into its constituent frequencies. It converts a function from its original domain (e.g. time) to a representation in the frequency domain.

What are eigenfunctions and eigenvalues?

Eigenfunctions are special functions that, when transformed by a linear operator, remain unchanged except for a scalar multiple (eigenvalue). In the context of Fourier Transform, eigenfunctions are the basis functions that are used to represent a given function in the frequency domain.

Why are eigenfunctions and eigenvalues important in Fourier Transform?

Eigenfunctions are important because they allow us to represent a function in the frequency domain as a linear combination of these basis functions. This simplifies the analysis of complex functions and makes it easier to manipulate them. Eigenvalues, on the other hand, give us information about the amplitude and phase of each frequency component in the transformed function.

How are eigenfunctions and eigenvalues calculated in Fourier Transform?

Eigenfunctions in Fourier Transform are the complex exponential functions, while the eigenvalues are the corresponding frequencies. These can be calculated using the Fourier Transform integral formula or by using the discrete Fourier Transform algorithm.

What is the physical significance of eigenfunctions and eigenvalues in Fourier Transform?

In addition to simplifying the analysis of complex functions, the eigenfunctions and eigenvalues in Fourier Transform have physical significance as they represent the different frequency components of a signal or function. This is useful in fields such as signal processing, image processing, and quantum mechanics.

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