Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Effects of the pseudo-gap on the field-induced kinetic energy density of
  Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ single crystals   We report on magnetization experiments from which we obtain the field-induced
kinetic energy density, $E_k$, in the superconducting phase of several
Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ single crystal samples. The kinetic energy
magnitude changes according to the characteristic reduction of the
single-electron density of states produced by the pseudogap in the underdoped
limit. Moreover, a remarkable peak of $E_k$ occurring at the specific holes
density $p\sim0.18$ is related to a van Hove singularity due to the pseudogap
closure. We also extracted the superfluid density, $\rho_s$. We conclude that
$E_k$ and $\rho_s$ are related to the pseudogap energy scale. This result is
understood as an evidence of the coexistence between superconductivity and the
pseudogap phenomenon in the Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ cuprate
compound.

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The categories of this paper are: supr-con
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The categories of this paper are: cmp-lg
10
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: atom-ph
2
The categories of this paper are: math
1
The categories of this paper are: cs
23
The categories of this paper are: solv-int
8
The categories of this paper are: hep-ex
30
The categories of this paper are: q-alg
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The categories of this paper are: eess
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The categories of this paper are: acc-phys
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The categories of this paper are: nucl-th
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The categories of this paper are: stat
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The categories of this paper are: hep-th
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The categories of this paper are: nucl-ex