What Causes Divergences in QFT?

  • Context: Graduate 
  • Thread starter Thread starter eljose
  • Start date Start date
  • Tags Tags
    Phsyics
Click For Summary
SUMMARY

The discussion centers on the causes of divergences in Quantum Field Theory (QFT), specifically examining integrals of the form \(\int_{0}^{\infty} dkk^{m}\) where \(m\) can take values from -1 to 5 or higher. It is established that most divergences can be expressed through these integrals, with the possibility of representing other divergences as \(\int_{0}^{\infty} dkF(k) = \sum_{r=0}^{\infty} a(r)\int_{0}^{\infty} dkk^{r}\). The conversation highlights the complexity introduced by overlapping divergences and subgraphs, particularly in loop integrals that may yield logarithmically divergent terms.

PREREQUISITES
  • Understanding of Quantum Field Theory (QFT)
  • Familiarity with integral calculus, particularly improper integrals
  • Knowledge of loop integrals and their significance in QFT
  • Concept of momentum in quantum mechanics, specifically \(\hbar{k}\)
NEXT STEPS
  • Research the implications of logarithmic divergences in QFT
  • Study the role of subgraphs in loop integrals
  • Explore methods for regularization of divergent integrals in QFT
  • Learn about the renormalization process in Quantum Field Theory
USEFUL FOR

The discussion is beneficial for theoretical physicists, graduate students in physics, and researchers focusing on Quantum Field Theory and its mathematical foundations.

eljose
Messages
484
Reaction score
0
more than a proper topic this is a question...my question is if all the divergences that appear in QFT are due to integrals in the form:

\int_{0}^{\infty}dkk^{m}

with m=-1 (logarithmic),0,1,2,3,4,5,...

if not i think that for any other divergences you could express them as:

\int_{0}^{\infty}dkF(k)= \sum_{r=0}^{\infty}a(r)\int_{0}^{\infty}dkk^{r}

r=0,1,2,3,4,5,... and a(r) the coefficients of the series expansion for the function F(k) of course K here is the "momentum" modulus p=\hbar{k}
 
Physics news on Phys.org
Roughly speaking yes, all integrals are of this form. Though there is the issue of overlapping divergences and subgraphs, e.g. a single loop integral might result in a logarithmically divergent term that contains the integration variable of another loop integral.
 

Similar threads

  • · Replies 2 ·
Replies
2
Views
1K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 9 ·
Replies
9
Views
3K
  • · Replies 12 ·
Replies
12
Views
3K
  • · Replies 4 ·
Replies
4
Views
3K
  • · Replies 1 ·
Replies
1
Views
3K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 9 ·
Replies
9
Views
3K