Help with the derivative of the Dirac delta

Click For Summary
The discussion centers on developing an equation involving the Dirac delta function, specifically addressing the assumption that \(\delta(r_2-r_1)^2 = 0\), a concept related to renormalization. Participants highlight that the square of a delta distribution is undefined and express confusion over the sequence and clarity of the equations presented. Suggestions include using LaTeX for clearer communication and exploring complex coordinates for integration. There is a mention of expanding the Schrödinger equation to simplify the analysis. Overall, the conversation emphasizes the need for clearer presentation and understanding of the mathematical concepts involved.
Delerion24
Messages
1
Reaction score
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 ?
 
Physics news on Phys.org
@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.
 
  • Like
Likes Wrichik Basu, topsquark and robphy
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?
 
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:
 
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.
 
So is there some elegant way to do this or am I just supposed to follow my nose and sub the Taylor expansions for terms in the two boost matrices under the assumption ##v,w\ll 1##, then do three ugly matrix multiplications and get some horrifying kludge for ##R## and show that the product of ##R## and its transpose is the identity matrix with det(R)=1? Without loss of generality I made ##\mathbf{v}## point along the x-axis and since ##\mathbf{v}\cdot\mathbf{w} = 0## I set ##w_1 = 0## to...

Similar threads

Replies
0
Views
2K
Replies
5
Views
4K
Replies
4
Views
2K
  • · Replies 17 ·
Replies
17
Views
2K
  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 5 ·
Replies
5
Views
4K
Replies
8
Views
2K
  • · Replies 9 ·
Replies
9
Views
4K
  • · Replies 25 ·
Replies
25
Views
4K
  • · Replies 2 ·
Replies
2
Views
2K