Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the topological structure of the QCD vacuum   A review of results from lattice studies using improved and scale controlled
cooling methods is presented and their significance is discussed. The
improvement of the action ensures stable instanton solutions of physical sizes.
The scale controlled cooling can be generally used as a gauge invariant low
pass filter to extract the physics from noisy MC configurations; in particular
it preserves instanton-antiinstanton pairs selected according to their
interaction. We apply these methods to analyze various features of the
topological structure of the Yang-Mills vacuum in a scaling invariant way.

17
The categories of this paper are: q-fin
36
The categories of this paper are: cmp-lg
15
The categories of this paper are: nucl-ex
6
The categories of this paper are: astro-ph
8
The categories of this paper are: hep-ex
16
The categories of this paper are: stat
3
The categories of this paper are: physics
26
The categories of this paper are: bayes-an
27
The categories of this paper are: comp-gas
35
The categories of this paper are: mtrl-th
5
The categories of this paper are: gr-qc
2
The categories of this paper are: math
12
The categories of this paper are: nucl-th
30
The categories of this paper are: q-alg
19
The categories of this paper are: eess
20
The categories of this paper are: acc-phys