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Number of distinct diagrams. 
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#1
Aug708, 11:18 AM

P: 15

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 


#2
Jan411, 09:06 PM

P: 467

to be honest, i have no idea.



#3
Jan511, 07:29 AM

Sci Advisor
P: 2,470

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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