Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Quantum decay of the persistent current in a Josephson junction ring   We study the persistent current in a ring consisting of N >> 1 Josephson
junctions threaded by the magnetic flux. When the dynamics of the ring is
dominated by the capacitances of the superconducting islands the system is
equivalent to the xy spin system in 1+1 dimensions at the effective temperature
T*=(2JU)^(1/2), with J being the Josephson energy of the junction and U being
the charging energy of the superconducting island. The numerical problem is
challenging due to the absence of thermodynamic limit and slow dynamics of the
Kosterlitz-Thouless transition. It is investigated on lattices containing up to
one million sites. At T << J the quantum phase slips are frozen. The low-T*
dependence of the persistent current computed numerically agrees quantitatively
with the analytical formula provided by the spin-wave approximation. The high-
T* behavior depends strongly on the magnetic flux and on the number of
superconducting islands N. Depending on the flux, the persistent current gets
destroyed by the phase slips and/or by the superconductor-insulator transition
on increasing T*.

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The categories of this paper are: solv-int
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The categories of this paper are: atom-ph
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The categories of this paper are: hep-ph
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The categories of this paper are: cs
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The categories of this paper are: acc-phys
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The categories of this paper are: nucl-ex
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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: stat
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The categories of this paper are: chem-ph
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The categories of this paper are: astro-ph
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The categories of this paper are: plasm-ph
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The categories of this paper are: math-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: eess
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The categories of this paper are: patt-sol