Resummation of divergent integrals.

In summary, the conversation discusses the possibility of finding resummation methods for divergent series and integrals. It is mentioned that there is a method for divergent series, but not for integrals. The question is raised as to why there is no method for integrals and whether it would be useful, especially in QFT where many integrals diverge.
  • #1
mhill
189
1
if we can obtain resummation methods for divergent series such as

[tex] 1-1+1-1+1-1+1-1+... [/tex] or [tex] 1!-2!+3!-4!+.. [/tex]

my question is why is there no method to deal with divergent integrals like [tex] \int_{0}^{\infty} dx x^{s-1} [/tex] or [tex] \int_{0}^{\infty} dx (x+1)^{-1} (x^{3}+x) [/tex]
 
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  • #2
Do you mean the ramanujan sum?
 
  • #3
*-<|:-D=<-< said:
Do you mean the ramanjuan sum?


yes something similar but for integrals instead of being valid only for series .
 
  • #4
mhill said:
my question is why is there no method to deal with divergent integrals


My question is: why should there be? If you can think of a good reason, then perhaps you will find a way to do it. (Is this you again, eljose?)
 
  • #5
Can you recall any method of writing an integral as a sum?
 
  • #6
matt grime said:
My question is: why should there be? If you can think of a good reason, then perhaps you will find a way to do it. (Is this you again, eljose?)

the question is that for example in QFT many integrals diverge as [tex] \int_{0}^{\infty} dk k^{n} [/tex] that would be a good reason to try finding resummed values of integrals.
 

Related to Resummation of divergent integrals.

1. What is "resummation of divergent integrals"?

Resummation of divergent integrals is a mathematical technique used to handle integrals that have infinite or divergent values. It involves rearranging the terms of the integral to obtain a finite and meaningful result.

2. Why are divergent integrals a problem in scientific research?

Divergent integrals can arise in scientific research when dealing with complex mathematical models or physical phenomena. These integrals can result in nonsensical or undefined solutions, making it difficult to interpret and apply the results.

3. How does resummation of divergent integrals work?

Resummation of divergent integrals involves identifying the problematic term(s) in the integral and using mathematical techniques such as regularization or renormalization to modify the integral in a way that produces a finite result. This can involve subtracting infinities or redefining the integral in terms of a new variable.

4. What are the applications of resummation of divergent integrals?

Resummation of divergent integrals has applications in various fields of science, including quantum field theory, statistical mechanics, and cosmology. It is also used in the development of mathematical models and theories, as well as in practical engineering applications.

5. Are there any limitations to resummation of divergent integrals?

While resummation of divergent integrals is a powerful tool, it is not a universal solution to all problems involving divergent integrals. It may not be applicable in certain situations, or it may require further modifications and approximations to obtain accurate results. Additionally, the interpretation of the results may require caution and further analysis.

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