Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Non-perturbative dynamics of the heavy-light quark system in the
  non-recoil limit   Starting from the relativistic gauge-invariant quark-antiquark Green function
we obtain the relevant interaction in the one-body limit, which can be
interpreted as the kernel of a non-perturbative Dirac equation. We study this
kernel in different kinematic regions, reproducing, in particular, for heavy
quark the potential case and sum rules results. We discuss the relevance of the
result for heavy-light mesons and the relation with the phenomenological Dirac
equations used up to now in the literature.

22
The categories of this paper are: chao-dyn
36
The categories of this paper are: cmp-lg
21
The categories of this paper are: adap-org
37
The categories of this paper are: supr-con
25
The categories of this paper are: patt-sol
16
The categories of this paper are: stat
4
The categories of this paper are: cond-mat
9
The categories of this paper are: nlin
32
The categories of this paper are: atom-ph
13
The categories of this paper are: quant-ph
19
The categories of this paper are: eess
20
The categories of this paper are: acc-phys
27
The categories of this paper are: comp-gas
7
The categories of this paper are: hep-th
5
The categories of this paper are: gr-qc
6
The categories of this paper are: astro-ph