Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: PNJL model for adjoint fermions   Recent work on QCD-like theories has shown that the addition of adjoint
fermions obeying periodic boundary conditions to gauge theories on R^3 X S^1
can lead to a restoration of center symmetry and confinement for sufficiently
small circumference L of S^1. At small L, perturbation theory may be used
reliably to compute the effective potential for the Polyakov loop P in the
compact direction. Periodic adjoint fermions act in opposition to the gauge
fields, which by themselves would lead to a deconfined phase at small L. In
order for the fermionic effects to dominate gauge field effects in the
effective potential, the fermion mass must be sufficiently small. This
indicates that chiral symmetry breaking effects are potentially important. We
develop a Polyakov-Nambu-Jona Lasinio (PNJL) model which combines the known
perturbative behavior of adjoint QCD models at small L with chiral symmetry
breaking effects to produce an effective potential for the Polyakov loop P and
the chiral order parameter psi-bar psi. A rich phase structure emerges from the
effective potential. Our results are consistent with the recent lattice
simulations of Cossu and D'Elia, which found no evidence for a direct
connection between the small-L and large-L confining regions. Nevertheless, the
two confined regions are connected indirectly if an extended field theory model
with an irrelevant four-fermion interaction is considered. Thus the small-L and
large-L regions are part of a single confined phase.

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The categories of this paper are: solv-int
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The categories of this paper are: hep-th
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The categories of this paper are: gr-qc
2
The categories of this paper are: math
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The categories of this paper are: chao-dyn
33
The categories of this paper are: plasm-ph
6
The categories of this paper are: astro-ph
10
The categories of this paper are: q-bio
30
The categories of this paper are: q-alg
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The categories of this paper are: nlin
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The categories of this paper are: funct-an
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The categories of this paper are: atom-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: dg-ga
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The categories of this paper are: physics
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The categories of this paper are: nucl-ex