Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The 2PI effective theory at next-to-leading order using the functional
  renormalization group   We consider a symmetric scalar theory with quartic coupling in 4-dimensions.
We show that the 4 loop 2PI calculation can be done using a renormalization
group method. The calculation involves one bare coupling constant which is
introduced at the level of the Lagrangian and is therefore conceptually simpler
than a standard 2PI calculation, which requires multiple counterterms. We
explain how our method can be used to do the corresponding calculation at the
4PI level, which can not be done using any known method by introducing
counterterms.

6
The categories of this paper are: astro-ph
28
The categories of this paper are: alg-geom
11
The categories of this paper are: hep-lat
18
The categories of this paper are: econ
5
The categories of this paper are: gr-qc
2
The categories of this paper are: math
27
The categories of this paper are: comp-gas
16
The categories of this paper are: stat
13
The categories of this paper are: quant-ph
14
The categories of this paper are: math-ph
32
The categories of this paper are: atom-ph
15
The categories of this paper are: nucl-ex
4
The categories of this paper are: cond-mat
26
The categories of this paper are: bayes-an
30
The categories of this paper are: q-alg
37
The categories of this paper are: supr-con