Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Character Expansion, Zeros of Partition Function and $\theta$-term in
  U(1) Gauge Theory   Character expansion developed in real space renormalization group (RSRG)
approach is applied to U(1) lattice gauge theory with $\th$-term in 2
dimensions. Topological charge distribution $P(Q)$ is shown to be of Gaussian
form at any $\b$(inverse coupling constant). The partition function $Z(\th)$ at
large volume is shown to be given by the elliptic theta function. It provides
the information of the zeros of partition function as an analytic function of
$\ze= e^{i \th}$ ($\th$ = theta parameter). These partition function zeros lead
to the phase transition at $\th=\pi$. Analytical results will be compared with
the MC simulation results. In MC simulation, we adopt (i)``set method" and
(ii)``trial function method".

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The categories of this paper are: funct-an
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The categories of this paper are: solv-int
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The categories of this paper are: nucl-th
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The categories of this paper are: comp-gas
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The categories of this paper are: acc-phys
10
The categories of this paper are: q-bio
18
The categories of this paper are: econ
33
The categories of this paper are: plasm-ph
26
The categories of this paper are: bayes-an
9
The categories of this paper are: nlin
2
The categories of this paper are: math
1
The categories of this paper are: cs
19
The categories of this paper are: eess
4
The categories of this paper are: cond-mat
5
The categories of this paper are: gr-qc
0
The categories of this paper are: hep-ph