Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Observation of Multi-Gap Superconductivity in GdO(F)FeAs by Andreev
  Spectroscopy   We have studied current-voltage characteristics of Andreev contacts in
polycrystalline GdO$_{0.88}$F$_{0.12}$FeAs samples with bulk critical
temperature ${T_c}$ = (52.5 \pm 1)K using break-junction technique. The data
obtained cannot be described within the single-gap approach and suggests the
existence of a multi-gap superconductivity in this compound. The large and
small superconducting gap values estimated at T = 4.2K are {\Delta}L = 10.5 \pm
2 meV and {\Delta}S = 2.3 \pm 0.4 meV, respectively.

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The categories of this paper are: comp-gas
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The categories of this paper are: funct-an
2
The categories of this paper are: math
13
The categories of this paper are: quant-ph
3
The categories of this paper are: physics
21
The categories of this paper are: adap-org
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The categories of this paper are: math-ph
12
The categories of this paper are: nucl-th
8
The categories of this paper are: hep-ex
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The categories of this paper are: q-alg
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The categories of this paper are: hep-th
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The categories of this paper are: patt-sol
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The categories of this paper are: solv-int
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The categories of this paper are: alg-geom
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The categories of this paper are: supr-con
15
The categories of this paper are: nucl-ex