Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Instanton contributions to Wilson loops with general winding number in
  two dimensions and the spectral density   The exact expression for Wilson loop averages winding n times on a closed
contour is obtained in two dimensions for pure U(N) Yang-Mills theory and,
rather surprisingly, it displays an interesting duality in the exchange $n
\leftrightarrow N$. The large-N limit of our result is consistent with previous
computations. Moreover we discuss the limit of small loop area ${\cal A}$,
keeping $n^2 {\cal A}$ fixed, and find it coincides with the zero-instanton
approximation. We deduce that small loops, both at finite and infinite
"volume", are blind to instantons. Next we check the non-perturbative result by
resumming 't Hooft-CPV and Wu-Mandelstam-Leibbrandt (WML)-prescribed
perturbative series, the former being consistent with the exact result, the
latter reproducing the zero-instanton contribution. A curious interplay between
geometry and algebraic invariants is observed. Finally we compute the spectral
density of the Wilson loop operator, at large $N$, via its Fourier
representation, both for 't Hooft and WML: for small area they exhibit a gap
and coincide when the theory is considered on the sphere $S^2$.

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The categories of this paper are: funct-an
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The categories of this paper are: math-ph
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The categories of this paper are: nucl-th
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The categories of this paper are: solv-int
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The categories of this paper are: bayes-an
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The categories of this paper are: adap-org
8
The categories of this paper are: hep-ex
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The categories of this paper are: alg-geom
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The categories of this paper are: ao-sci
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The categories of this paper are: stat
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The categories of this paper are: astro-ph
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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: quant-ph
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The categories of this paper are: supr-con
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The categories of this paper are: cmp-lg