Calculating Base State for the H Atom using Inverse Fourier Transform

In summary, the inverse Fourier transform is a mathematical operation that allows for the calculation of various functions.
  • #1
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Inverse Fourier Transform

I have to calculate (don't take in account the units, obviously the're extrange)

[tex]
\phi (r)=\frac{1}{(2\pi\hbar)^{3/2}}\int d^{3}p\hspace{7mm}{e^{i\frac{-p\cdot r}{\hbar}}\Psi(p)} [/tex]

[tex]
\Psi(p)=\frac{B}{(1+\frac{p^2}{m^2})^2}
[/tex]
I know that

[tex]
d^{3}p=p^{2}Sin(\theta)dpd\theta d\phi[/tex]

So i do

[tex]
\phi (r)=\frac{1}{(2\pi\hbar)^{3/2}} \int p^{2}Sin(\theta)dpd\theta d\phi\hspace{7mm}{e^{i\frac{-p\cdot r Cos(\theta)}{\hbar}}\frac{B}{(1+\frac{p^2}{m^2})^2}
} [/tex]

but i use the change of variables

[tex]
u=Cos(\theta);du=-Sin(\theta)d\theta [/tex]

And the the integral take the form


[tex]
\phi (r)=\frac{2\pi}{(2\pi\hbar)^{3/2}} \int_{1}^{-1}\int_{0}^{\infty}p^{2}dpdu \hspace{7mm}{e^{i\frac{-p\cdot r u}{\hbar}}\frac{B}{(1+\frac{p^2}{m^2})^2}
} [/tex]
 
Last edited:
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  • #2
Integrating

[tex] \phi (r)=\frac{2\pi} {(2\pi\hbar)^{3/2}} B \int_{0}^{\infty}pdp \hspace{7mm} \frac{\left(e^{i\frac{p r}{\hbar}}-e^{i\frac{p r}{\hbar}} \right){\frac{i p r}{hbar}\frac{1}{(1+\frac{p^2}{m^2})^2} [/tex]

Multipliying for [tex]\frac{2}{2}[/tex] to form a cosine, so it is

[tex]
\phi (r)=\frac{2\pi} {(2\pi\hbar)^{3/2}}\frac{2 B\hbar}{i r} \int_{0}^{\infty}pdp \hspace{7mm} Cos(\frac{p r}{\hbar})\frac{1}{(1+\frac{p^2}{m^2})^2}
} [/tex]
 
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  • #3
Bu the las integral, it is just a nightmare... the results froma Mathetmatica 6.1 is:

[tex]\frac{1}{2} m^2 \sqrt{\pi } MeigerG[{{0},{}},{{0,1},{\frac{1}{2}},\frac{m^2 r^2}{4\hbar^2}]
[/tex]

i as expecting the base level for the H atom [tex]\phi (r)[/tex], so if somebody could help me please...
 
Last edited:
  • #4
Na i found my error was a Sine not a cosine what I get afeter I do the first integral in du, I don't know why the page don't uptadete what I've write, but that was the error, mulltiply bi 2i/2i and you will get the base state for the H atom, THE ANSWER...
first part of the trip...
 

1. What is the Inverse Fourier Transform?

The Inverse Fourier Transform is a mathematical operation that takes a signal represented in the frequency domain and converts it back to the time domain. It is the reverse process of the Fourier Transform, which converts a time-domain signal into its frequency components.

2. Why is the Inverse Fourier Transform important?

The Inverse Fourier Transform is important because it allows us to analyze signals in both the time and frequency domains. This is useful in a variety of fields, such as signal processing, telecommunications, and image processing.

3. How is the Inverse Fourier Transform calculated?

The Inverse Fourier Transform is calculated using a mathematical formula that involves complex numbers. It is typically performed using computer algorithms, such as the Fast Fourier Transform (FFT), which is more efficient for large datasets.

4. What is the relationship between the Inverse Fourier Transform and the Fourier Transform?

The Inverse Fourier Transform and the Fourier Transform are inverse operations of each other. This means that applying the Fourier Transform to a signal and then applying the Inverse Fourier Transform to the result will yield the original signal.

5. What are some practical applications of the Inverse Fourier Transform?

The Inverse Fourier Transform has many practical applications, including audio and image compression, noise reduction, signal filtering, and spectrum analysis. It is also used in fields such as astronomy, medical imaging, and geophysics for data analysis and visualization.

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