Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Monopole and instanton effects in QCD   We aim to show the effects of the magnetic monopoles and instantons in
quantum chromodynamics (QCD) on observables; therefore, we introduce a monopole
and anti-monopole pair in the QCD vacuum of a quenched SU(3) by applying the
monopole creation operator to the vacuum. We calculate the eigenvalues and
eigenvectors of the overlap Dirac operator that preserves the exact chiral
symmetry in lattice gauge theory using these QCD vacua. We then investigate the
effects of magnetic monopoles and instantons. First, we confirm the monopole
effects as follows: (i) The monopole creation operator makes the monopoles and
anti-monopoles in the QCD vacuum. (ii) A monopole and anti-monopole pair
creates an instanton or anti-instanton without changing the structure of the
QCD vacuum. (iii) The monopole and anti-monopole pairs change only the scale of
the spectrum distribution without affecting the spectra of the Dirac operator
by comparing the spectra with random matrix theory. Next, we find the instanton
effects by increasing the number density of the instantons and anti-instantons
as follows: (iv) The decay constants of the pseudoscalar increase. (v) The
values of the chiral condensate, which are defined as negative numbers,
decrease. (vi) The light quarks and the pseudoscalar mesons become heavy. The
catalytic effect on the charged pion is estimated using the numerical results
of the pion decay constant and the pion mass. (vii) The decay width of the
charged pion becomes wider than the experimental result, and the lifetime of
the charged pion becomes shorter than the experimental result. These are the
effects of the monopoles and instantons in QCD.

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The categories of this paper are: econ
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The categories of this paper are: q-bio
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The categories of this paper are: gr-qc
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The categories of this paper are: q-fin
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The categories of this paper are: supr-con
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The categories of this paper are: math
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The categories of this paper are: cs
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The categories of this paper are: comp-gas
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The categories of this paper are: atom-ph
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The categories of this paper are: nucl-th
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The categories of this paper are: plasm-ph
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The categories of this paper are: chao-dyn
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The categories of this paper are: adap-org
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The categories of this paper are: funct-an
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The categories of this paper are: physics
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The categories of this paper are: cmp-lg