Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Realization of Artificial Ice Systems for Magnetic Vortices in a
  Superconducting MoGe Thin-film with Patterned Nanostructures   We report an anomalous matching effect in MoGe thin films containing pairs of
circular holes arranged in such a way that four of those pairs meet at each
vertex point of a square lattice. A remarkably pronounced fractional matching
was observed in the magnetic field dependences of both the resistance and the
critical current. At the half matching field the critical current can be even
higher than that at zero field. This has never been observed before for
vortices in superconductors with pinning arrays. Numerical simulations within
the nonlinear Ginzburg-Landau theory reveal a square vortex ice configuration
in the ground state at the half matching field and demonstrate similar
characteristic features in the field dependence of the critical current,
confirming the experimental realization of an artificial ice system for
vortices for the first time.

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The categories of this paper are: funct-an
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The categories of this paper are: atom-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: alg-geom
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The categories of this paper are: supr-con
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The categories of this paper are: gr-qc
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The categories of this paper are: hep-lat
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The categories of this paper are: adap-org
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The categories of this paper are: nucl-ex
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The categories of this paper are: eess
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The categories of this paper are: solv-int
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The categories of this paper are: math
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The categories of this paper are: cmp-lg
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The categories of this paper are: patt-sol
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The categories of this paper are: chao-dyn
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The categories of this paper are: hep-th