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Difficulty in the Fermi-Liquid-Based Theory for the In-Plane Magnetic Anisotropy in Untwinned High-T_c Superconductor
Recently, Eremin and Manske [1] presented a oneband Fermi-liquid theory for
the in-plane magnetic anisotropy in untwinned high-Tc superconductor
YBa2Cu3O6:85 (YBCO). They claimed that they found good agreement with inelastic
neutron scattering (INS) spectra. In this Comment, we point out that their
conclusion on this important problem may be questionable due to an error in
logic about the orthorhombicity delta_0 characterizing the lattice structure of
YBCO. In Ref. [1], a single band at delta_0>0 is proved to be in accordance
with the angle resolved photoemission spectroscopy (ARPES) on untwinned YBCO.
But in their Erratum in PRL[3], they admit that delta_0= -0.03 was used to fit
the INS data. Hence publications [1,3] contain errors that we believe
invalidate their approach.Comment: This is a Comment on the paper of I. Eremin, and D. Manske, Phys.
Rev. Lett. 94, 067006(2005
Power-law behavior and condensation phenomena in disordered urn models
We investigate equilibrium statistical properties of urn models with
disorder. Two urn models are proposed; one belongs to the Ehrenfest class, and
the other corresponds to the Monkey class. These models are introduced from the
view point of the power-law behavior and randomness; it is clarified that
quenched random parameters play an important role in generating power-law
behavior. We evaluate the occupation probability with which an urn has
balls by using the concept of statistical physics of disordered systems. In
the disordered urn model belonging to the Monkey class, we find that above
critical density for a given temperature, condensation
phenomenon occurs and the occupation probability changes its scaling behavior
from an exponential-law to a heavy tailed power-law in large regime. We
also discuss an interpretation of our results for explaining of macro-economy,
in particular, emergence of wealth differentials.Comment: 16pages, 9figures, using iopart.cls, 2 new figures were adde
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