Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Thermal Fluctuations in d-wave Layered Superconductors   We study the thermal fluctuations of anisotropic order parameters (OP) in
layered superconductors. In particular, for copper oxides and a d-wave OP, we
present some experimental consequences of fluctuations in the direction normal
to the layers. It is shown that the c-axis penetration depth $\lambda_c$ can
have a "disorder-like" quadratic temperature dependence at low temperature.
  The fluctuations are analyzed in the framework of a Lawrence-Doniach model
with an isotropic Fermi surface. Anisotropies pin the orientation of the OP to
the crystallographic axes of the lattice. Then we study an extended t-J model
that fits Fermi suface data of bilayers $YBCO$ and $BSCCO$. This leads to a
d-wave OP with two possible orientations and, including the thermal
fluctuations, yields the announced temperature dependence of $\lambda_c$.
Furthermore a reservoir layer is introduced. It implies a finite density of
states at the Fermi energy which is successfully compared to conductance and
specific heat measurements.

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The categories of this paper are: dg-ga
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The categories of this paper are: patt-sol
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The categories of this paper are: q-fin
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The categories of this paper are: quant-ph
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The categories of this paper are: astro-ph
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The categories of this paper are: physics
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The categories of this paper are: hep-lat
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The categories of this paper are: comp-gas
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The categories of this paper are: solv-int
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The categories of this paper are: nlin
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The categories of this paper are: chao-dyn
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The categories of this paper are: stat
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The categories of this paper are: math-ph
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The categories of this paper are: atom-ph
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The categories of this paper are: eess
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The categories of this paper are: acc-phys