Hi!(adsbygoogle = window.adsbygoogle || []).push({});

I'm currently learning for my QFT exam with the book from srednicki (here as pdf: http://web.physics.ucsb.edu/~mark/ms-qft-DRAFT.pdf) and I am trying to understand the chapter "Effective field theory" (p. 185 in the pdf above)

He first introduces an ultraviolet cutoff Λ and then computes the path integral over all fields with momentum above Λ.

Then he defines the "Wilsonian effective action" and writes down the corresponding lagrangian

( (29.11) on p. 186 ).

-) How can one derive eq (29.11) (the lagrangian density of the Wilsonian effective action) ?

-) Why can one compute the new coefficients m^{2}(Λ) \alpha, λ(Λ), ... the way it is shown in eq (29.13) - (29.23) ?

I am not confused about how exactly the computation works, but with how he comes up with the ansatz itself. For example, why the new mass m(Λ) can be computed with eq (29.20)

Thanks in advance!

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# A Effective field theory in Srednicki's book

Have something to add?

Draft saved
Draft deleted

**Physics Forums | Science Articles, Homework Help, Discussion**