Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Critical theories for the pseudogap Kondo problem   We discuss quantum phase transitions in the pseudogap Kondo problem, which
describes a magnetic moment coupled to conduction electrons with a power-law
density of states, rho(omega) ~ |omega|^r. We show that different perturbative
expansions, together with renormalization group techniques, provide effective
low-energy field theories for the relevant critical fixed points. In
particular, we review expansions near the lower-critical and upper-critical
dimensions of the problem, being r=0 and r=1, respectively.

33
The categories of this paper are: plasm-ph
34
The categories of this paper are: chem-ph
12
The categories of this paper are: nucl-th
7
The categories of this paper are: hep-th
21
The categories of this paper are: adap-org
9
The categories of this paper are: nlin
35
The categories of this paper are: mtrl-th
13
The categories of this paper are: quant-ph
2
The categories of this paper are: math
16
The categories of this paper are: stat
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The categories of this paper are: cmp-lg
25
The categories of this paper are: patt-sol
19
The categories of this paper are: eess
37
The categories of this paper are: supr-con
29
The categories of this paper are: funct-an
20
The categories of this paper are: acc-phys