Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: While calculating RKKY interaction in graphene no theorist should do a
  cut-off without cause   In our previous work (E. Kogan, Phys. Rev. B 84, 115119 (2011)) we presented
calculation of RKKY interaction between two magnetic impurities in graphene
based on Matsubara Green's functions (MGF) in the coordinate -- imaginary time
representation. Now we present the calculation based on MGF in the coordinate
-- frequency representation. We claim that both approaches have an important
advantage over those based on zero temperature Green's functions (ZTGF), which
are very briefly reviewed in the beginning of the present work. The MGF
approaches, in distinction to the ZTGF approaches, operate only with the
convergent integrals from the start to the end of the calculation. The
coordinate -- frequency representation for the MGF turns out to be as
convenient as the coordinate -- imaginary time representation and allows to
easily consider the cases of doped and gapped graphene.

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The categories of this paper are: alg-geom
2
The categories of this paper are: math
16
The categories of this paper are: stat
20
The categories of this paper are: acc-phys
33
The categories of this paper are: plasm-ph
25
The categories of this paper are: patt-sol
11
The categories of this paper are: hep-lat
15
The categories of this paper are: nucl-ex
35
The categories of this paper are: mtrl-th
3
The categories of this paper are: physics
30
The categories of this paper are: q-alg
19
The categories of this paper are: eess
27
The categories of this paper are: comp-gas
13
The categories of this paper are: quant-ph
0
The categories of this paper are: hep-ph
37
The categories of this paper are: supr-con