Counting Distinct Diagrams in Scalar Field Theory

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SUMMARY

The discussion focuses on determining the number of distinct diagrams in a \(\phi^{4}\) scalar field theory, specifically through the expansion of the integral \(\int_{-\infty}^{\infty} dq e^{-\frac{1}{2}m^{2}q^{2}+Jq-\frac{\lambda}{4!}q^{4}}\) in powers of \(\lambda\) and \(J\). The user seeks a systematic method to calculate the total number of distinct diagrams to order \((\lambda^{n}, J^{m})\). The consensus suggests that while manual calculation reveals patterns, no established method exists for a more efficient solution.

PREREQUISITES
  • Understanding of scalar field theory, particularly \(\phi^{4}\) theory.
  • Familiarity with perturbative expansions in quantum field theory.
  • Knowledge of integral calculus, especially Gaussian integrals.
  • Experience with diagrammatic techniques in quantum field theory.
NEXT STEPS
  • Research diagrammatic techniques in quantum field theory.
  • Study perturbation theory applications in \(\phi^{4}\) theory.
  • Explore Tony Zee's "Quantum Field Theory in a Nutshell" for foundational concepts.
  • Investigate combinatorial methods for counting Feynman diagrams.
USEFUL FOR

Physicists, particularly those specializing in quantum field theory, graduate students studying \(\phi^{4}\) theory, and researchers looking to enhance their understanding of diagrammatic methods in theoretical physics.

whynothis
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I was just trying to think of a simple relation to find the number of distinct diagrams to a given order within a theory (specifically I am thinking of a [tex]\phi^{4}[/tex] scalar theory). I am reading Tony Zee's book and am working through his "baby problem" where he expands the integral:

[tex]\int_{-\inf}^{\inf} dq e^{-\frac{1}{2}m^{2}q^{2}+Jq-\frac{\lambda}{4!}q^{4}[/tex]

in both in powers of [tex]\lambda[/tex] and J so that we can pick out diagrams to a specific order in both.

So is there a way to find the total number of distinct diagrams to order [tex](\lambda^{n},J^{m})[/tex]?

Thanks in Advanced :smile:
 
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to be honest, i have no idea.
 
From personal experience, you just keep working these out by hand until you see a pattern. Or you get to a point where you give up. If there is a better way, I have not found it.
 

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