Question on UV and IR divergences

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SUMMARY

The discussion focuses on the nature of ultraviolet (UV) and infrared (IR) divergences in quantum field theory, specifically questioning whether all divergences can be expressed in the form of the integral \(\int_{0}^{\infty} dk. k^{m}\) where 'm' is an integer. It is established that UV divergences depend on the type of regulator used, while the nature of IR divergences remains less certain. The conversation also touches on the Fourier transform of convolutions involving derivatives of delta functions, indicating a complex relationship between these mathematical constructs.

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  • Understanding of quantum field theory concepts
  • Familiarity with UV and IR divergences
  • Knowledge of Fourier transforms and their properties
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  • Research different types of regulators used in quantum field theory
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This discussion is beneficial for theoretical physicists, mathematicians working in quantum field theory, and students seeking to deepen their understanding of divergences and Fourier transforms in advanced physics.

mhill
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no matter what theory we use , are all UV and IR divergences of the form ??

\int_{0}^{\infty} dk. k^{m} where 'm' is an integer

or there are another divergent integral different from a power-law or logarithmic divergence ?? , and another question , can be this true

i^{m+n}D^{m}\delta (w) D^{n}\delta (w)= Fourier. transform (\int_{-\infty}^{\infty}dt.t^{n}(x-t)^{m})

where i have used the fact that the Fourier transform of a convolution of two functions (f*g) is just the product of the Fourier transform F(w)G(w)
 
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UV divergences are of that form, but it depends on the type of regulator you use. I'm not sure about IR divergences.

I don't know what you mean by D^m\delta(\omega). A derivative?

D^m \delta(\omega) D^n \delta(\omega) \approx \int\!dt\,t^m e^{i \omega t}\int\!dx\,x^n e^{i \omega x}= \int\!dt\,\int\!dx\, t^m x^n e^{i \omega (x+ t)} = \int\!dx \left[\int\!dt\, t^m (x-t)^n \right] e^{i \omega x}
You will have to put in factors of i and pi and such.
 

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