Complex integral coming from a 1loop diagram

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SUMMARY

The discussion focuses on the computation of a complex integral arising from a one-loop Feynman diagram related to Luttinger liquid studies. The integral is expressed as \(\int_{-\Lambda}^{+\Lambda}dQ\int d\Omega\frac{1}{(\omega-\Omega)-iv(k-Q)}\frac{1}{\Omega-ivQ}\), where \(\omega\) and \(k\) represent the total energy and momentum of incoming fermions, respectively. The user seeks assistance in evaluating this integral, particularly after performing a partial fractions decomposition, which yields constants A and B that do not depend on \(\Omega\) or \(Q\). Verification of this result is requested to ensure accuracy.

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AdeBlackRune
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Hi,
i'm studing the divergent/convergent behavior of some feynman diagrams that emerge from the study of luttinger liquid. One of this diagrams has a loop inside it and loop-integrals has the following form:

[itex]\int_{-\Lambda}^{+\Lambda}dQ\int d\Omega\frac{1}{(\omega-\Omega)-iv(k-Q)}\frac{1}{\Omega-ivQ}[/itex]


where [itex]\omega[/itex]
and k are total energy and momentum of the incoming fermions and v the Fermi velocity. Could someone help me with the computation of this integral? It would not be hard but I'm blocked. The dQ integral is limited within a window [-L,+L]
 
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You can perform a partial fractions decomposition of the term:

$$\frac{1}{\omega-\Omega - i v(k-Q)}\frac{1}{\Omega - ivQ} = \frac{A}{\omega-\Omega - i v(k-Q)} + \frac{B}{\Omega - ivQ}.$$

I found that A and B end up not depending on ##\Omega## or ##Q##, but double check that I didn't make an error.
 

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