Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The average kinetic energy density of Cooper pairs above $T_c$ in ${\rm
  YBa_2Cu_3O_{7-x}}$, ${\rm Bi_2Sr_2CaCu_2O_{8+\delta}}$, and ${\rm Nb}$   We have obtained isofield curves for the square root of the average kinetic
energy density of the superconducting state for three single crystals of
underdoped $YBa_2Cu_3O_{7-x}$, an optimally doped single crystal of
$Bi_2Sr_2CaCu_2O_{8+\delta}$, and Nb. These curves, determined from isofield
magnetization versus temperature measurements and the virial theorem of
superconductivity, probe the order parameter amplitude near the upper critical
field. The striking differences between the Nb and the high-$T_c$ curves
clearly indicate for the latter cases the presence of a unique superconducting
condensate below and above $T_c$.

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The categories of this paper are: alg-geom
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The categories of this paper are: hep-lat
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The categories of this paper are: cs
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The categories of this paper are: hep-ex
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The categories of this paper are: patt-sol
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The categories of this paper are: supr-con
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The categories of this paper are: stat
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The categories of this paper are: chao-dyn
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The categories of this paper are: q-bio
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The categories of this paper are: econ
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The categories of this paper are: acc-phys
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The categories of this paper are: dg-ga
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The categories of this paper are: mtrl-th
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The categories of this paper are: ao-sci
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The categories of this paper are: chem-ph
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The categories of this paper are: adap-org