Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Fermi surfaces of iron-pnictide high-Tc superconductors from the limit
  of local magnetic moments   A 2-orbital t-J model over the square lattice that describes low-energy
electronic excitations in iron-pnictide high-Tc superconductors is analyzed
with Schwinger-boson-slave-fermion meanfield theory and by exact numerical
diagonalization on a finite system. A quantum critical point (QCP) is
identified that separates a commensurate spin-density wave (cSDW) state at
strong Hund's rule coupling from a hidden half-metal state at weak Hund's rule
coupling when inter-orbital hole hopping is suppressed. Low-energy spinwaves
that disperse anisotropically from cSDW momenta are predicted at the QCP.
Nested Fermi surfaces similar to those observed experimentally in iron-pnictide
materials are also predicted in such case.

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The categories of this paper are: physics
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The categories of this paper are: math
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The categories of this paper are: econ
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The categories of this paper are: mtrl-th
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The categories of this paper are: hep-ex
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The categories of this paper are: adap-org
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The categories of this paper are: dg-ga
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The categories of this paper are: nlin
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The categories of this paper are: bayes-an
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The categories of this paper are: eess
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The categories of this paper are: gr-qc
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The categories of this paper are: chao-dyn
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The categories of this paper are: hep-lat
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The categories of this paper are: q-bio
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The categories of this paper are: q-fin
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The categories of this paper are: atom-ph