Help with the derivative of the Dirac delta

In summary, the conversation revolves around developing equation 21 and discussing the validity of certain conditions. The use of delta distributions and holomorphic functions are mentioned as potential approaches to solving the problem. However, the conversation becomes unclear due to incomplete and mis-sequenced information.
  • #1
Delerion24
1
0
Homework Statement
Try developed this expression
Relevant Equations
The equations are in the images
Desarrollo 8b parte 1.PNG
Desarrollo 8b parte 2.PNG


My goal is to develop the equation 21. You should asume that \delta(r_2-r_1)^2 =0. These is named renormalization. Then my question is , do my computes are correct with previous condition ?
 
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  • #2
@Delerion24 -- Please make it a habit to post your work at PF using LaTeX, not via images. You can click on the "LaTeX Guide" link below the Edit window for our LaTeX tutorial. What software did you use to write the equations in your image? Perhaps it is easy to port your work to LaTeX and add that as a reply? Thanks.
 
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  • #3
I guess this is a Distributional derivative, or there's something else I'm not aware of here? I mean, are we referring to the Dirac delta Distribution. i.e., Generalized function?
 
  • #4
Delerion24 said:
Homework Statement: Try developed this expression
Relevant Equations: The equations are in the images

View attachment 314422View attachment 314423

My goal is to develop the equation 21. You should asume that \delta(r_2-r_1)^2 =0. These is named renormalization.
No, the square of a delta distribution is undefined.
Where did your eq(21) come from? You say that it "is" (8b). But then later you say that eq(26) is 8b. Then you say "9 isn't 2", which I guess refers to other equations you haven't shown.

It's very hard to help when you all you show us is a mis-sequenced, incomplete, mess. :headbang:
 
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  • #5
I just started reading about holomorphic functions, maybe switch to complex coordinates and integrate around a contour. If you expand your Schrödinger equation correctly, then you should just see the wave function with a time evolution operator, like a decaying exponential tacked on the side. Let me think about this one.
 

FAQ: Help with the derivative of the Dirac delta

How do you find the derivative of the Dirac delta function?

To find the derivative of the Dirac delta function, you can use the property that the derivative of the Heaviside step function is the Dirac delta function itself. Therefore, the derivative of the Dirac delta function is often represented as the derivative of the Heaviside step function.

What is the derivative of the Heaviside step function?

The derivative of the Heaviside step function is the Dirac delta function. This relationship is commonly used to find the derivative of the Dirac delta function by representing it as the derivative of the Heaviside step function.

Can the Dirac delta function be differentiated like a regular function?

No, the Dirac delta function cannot be differentiated like a regular function because it is a distribution rather than a function. However, the derivative of the Dirac delta function can be represented using the derivative of the Heaviside step function.

Why is the derivative of the Dirac delta function important in physics and engineering?

The derivative of the Dirac delta function is important in physics and engineering because it allows for the modeling of impulse or instantaneous events in systems. By using the Dirac delta function and its derivative, engineers and physicists can analyze and solve problems involving impulse responses and instantaneous changes.

Are there any specific rules or properties to keep in mind when differentiating the Dirac delta function?

One important property to keep in mind when differentiating the Dirac delta function is that it is an odd function, which means that its derivative is an even function. Additionally, the derivative of the Dirac delta function is often represented using the derivative of the Heaviside step function for easier calculations.

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