Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Kosterlitz-Thouless transition on the worldsheet of the QCD string   We investigate the properties of the QCD string in the Euclidean SU(N) pure
gauge theory when the space-time dimensions transverse to it are periodic. We
propose a generalisation of the Luscher-Weisz effective string action for the
flux-tube energy levels at finite L_perp. As the size of one transverse
dimension is varied, we predict a Kosterlitz-Thouless transition of the
worldsheet field theory driven by vortices, after which the periodic component
of the worldsheet displacement vector develops a mass gap and the effective
central charge drops by one unit. The universal properties of the transition
are emphasized.

7
The categories of this paper are: hep-th
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The categories of this paper are: q-fin
35
The categories of this paper are: mtrl-th
31
The categories of this paper are: ao-sci
37
The categories of this paper are: supr-con
23
The categories of this paper are: solv-int
30
The categories of this paper are: q-alg
1
The categories of this paper are: cs
8
The categories of this paper are: hep-ex
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The categories of this paper are: math-ph
16
The categories of this paper are: stat
19
The categories of this paper are: eess
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The categories of this paper are: nucl-th
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The categories of this paper are: comp-gas
2
The categories of this paper are: math
15
The categories of this paper are: nucl-ex