Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Absence of a True Vortex-Glass Phase above the Bragg Glass Transition
  Line in Bi-2212   In magnetic measurements on Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ (Bi-2212)
single crystals, a general peak with a dynamical feature on both $S-H$ and
$S-T$ curves was found with S the magnetic relaxation rate. At higher fields,
the characteristic exponent $\mu$ becomes negative, together with the positive
curvature of $logE$ vs. $ logj$ and the scaling based on the 2D vortex glass
theory or plastic creep theory, we conclude that the vortex motion above the
second peak is plastic when $j\to 0$ and there is no vortex glass phase at
finite temperatures in Bi-2212. The peak of S is then explained as the
crossover between different meta-stable vortex states.

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The categories of this paper are: eess
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The categories of this paper are: q-fin
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The categories of this paper are: adap-org
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The categories of this paper are: comp-gas
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The categories of this paper are: cmp-lg
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The categories of this paper are: hep-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: nlin
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The categories of this paper are: astro-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: math
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The categories of this paper are: supr-con
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The categories of this paper are: alg-geom
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The categories of this paper are: atom-ph
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The categories of this paper are: hep-lat
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The categories of this paper are: acc-phys