Plotting the approximation of the Dirac delta function

  • #1
Lambda96
158
59
Homework Statement
Plot ##g^{\epsilon}(x)## for ##\epsilon=1## , ##\epsilon=\frac{1}{2}## and ##\epsilon=\frac{1}{4}##
Relevant Equations
none
Hi,

I am not sure if I have solved the following task correctly

Bildschirmfoto 2024-01-15 um 16.34.11.png


I did the plotting in mathematica and got the following

Bildschirmfoto 2024-01-15 um 16.48.02.png

Would the plots be correct? What is meant by check for normalization, is the following meant?

For the approximation for ##\epsilon > 0##, does it mean that for the area of ## 0 < x < \epsilon## the area must be 1, so for the case ##\epsilon=1## the total area would be 1, the half for ## 0 < x < \epsilon## would then be ##\frac{1}{2}##, so the normalization constant should be 2?
 
Physics news on Phys.org
  • #2
To sketch usually means to draw by hand. Is this behavior that you expected? Look at the formula. Between minus epsilon and +epsilon, what is the function doing (does it change with x)?

Normalization refers to the area under the "curve" equal to 1 over the entire spectrum. Do these graphs satisfy that?
 
Last edited:
  • Like
Likes Lambda96
  • #3
Lambda96 said:
Would the plots be correct?
Yes, those plots look correct.
Lambda96 said:
What is meant by check for normalization, is the following meant?
It means to check that the integral is 1.
Lambda96 said:
For the approximation for ##\epsilon > 0##, does it mean that for the area of ## 0 < x < \epsilon## the area must be 1,
No. It means that the area of ##- \epsilon < x < \epsilon ## must be 1.
Lambda96 said:
so for the case ##\epsilon=1## the total area would be 1, the half for ## 0 < x < \epsilon## would then be ##\frac{1}{2}##, so the normalization constant should be 2?
No. No further normalization is needed. The area between each graph and the x axis is already 1.
 
  • Like
Likes Lambda96
  • #4
Thank you scottdave and FactChecker for your help 👍👍
 
  • Like
Likes scottdave

1. How can the Dirac delta function be approximated through plotting?

The Dirac delta function can be approximated by using a sequence of functions that converge to it as their width approaches zero. This can be visualized by plotting these functions and observing how they get closer to resembling the Dirac delta function.

2. What are some commonly used functions for approximating the Dirac delta function?

Sigmoid functions, Gaussian functions, and sinc functions are commonly used to approximate the Dirac delta function. These functions have properties that allow them to closely resemble the Dirac delta function as their parameters are adjusted.

3. How does the accuracy of the approximation change with different functions?

The accuracy of the approximation can vary depending on the function used. Some functions may provide a closer approximation to the Dirac delta function than others, especially in certain regions of the plot. Experimenting with different functions can help determine which one best suits the desired approximation accuracy.

4. What role does the width parameter play in approximating the Dirac delta function?

The width parameter of the approximating functions determines how narrow or wide the peak of the function is. As the width parameter approaches zero, the function becomes more concentrated and resembles the Dirac delta function more closely. Adjusting this parameter can help fine-tune the approximation.

5. Are there any limitations to plotting the approximation of the Dirac delta function?

One limitation is that the Dirac delta function is not a true function in the conventional sense, making it impossible to plot directly. Instead, approximations are used to visualize its behavior. Additionally, the choice of approximating function and parameters can affect the accuracy of the plotted approximation.

Similar threads

  • Calculus and Beyond Homework Help
Replies
13
Views
489
  • Calculus and Beyond Homework Help
Replies
9
Views
552
  • Calculus and Beyond Homework Help
Replies
10
Views
377
  • Calculus and Beyond Homework Help
Replies
9
Views
2K
  • Calculus and Beyond Homework Help
Replies
19
Views
1K
  • Calculus and Beyond Homework Help
Replies
16
Views
1K
  • Calculus and Beyond Homework Help
Replies
9
Views
2K
  • Calculus and Beyond Homework Help
Replies
3
Views
2K
  • Calculus and Beyond Homework Help
Replies
1
Views
656
  • Calculus and Beyond Homework Help
Replies
7
Views
1K
Back
Top