Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Viscosities of Hot Gluon -- A Lattice QCD Study --   We present transport coefficients (shear viscosity, $\eta$, and bulk
viscosity, $\zeta$) for the gluon system obtained by the lattice QCD. This is
an indispensable calculation towards the understanding of ``New State of
Matter'' observed in RHIC. We study the temperature regions of RHIC ($1.4 \leq
T/T_c \leq 1.8$) and much higher ones up to $ T/T_c \sim 20$. In RHIC regions,
the ratio of shear viscosity to entropy density, $\eta/s$, is around $\sim
0.1-0.4$, and satisfies the KSS bound. At high temperature, $\eta$ becomes two
or three oder of magnitude larger. Our calculation has two limitations: (i) the
use of the quench approximation, i.e., without quark pair creation-annihilation
effects on vacuum, and (ii) the use of an ansatz for the spectral function. The
first point has been well studied in calculations of the spectroscopy and the
phase-transition behavior. To investigate the second point, we compare our
results with perturbative calculations in high $T$-regions, and also check the
effects of the modification of the spectral function on the viscosity.

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The categories of this paper are: physics
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The categories of this paper are: quant-ph
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The categories of this paper are: cond-mat
26
The categories of this paper are: bayes-an
30
The categories of this paper are: q-alg
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The categories of this paper are: astro-ph
28
The categories of this paper are: alg-geom
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The categories of this paper are: nucl-th
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The categories of this paper are: hep-ph
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The categories of this paper are: q-fin
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The categories of this paper are: plasm-ph
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The categories of this paper are: cmp-lg
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The categories of this paper are: comp-gas
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The categories of this paper are: funct-an
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The categories of this paper are: supr-con
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The categories of this paper are: dg-ga