Yoshifumi Morita

Quasiparticle Spectra around a Single Vortex in a {ital d} -Wave Superconductor

Using the Bogoliubov{emdash}de Gennes equation, we study the quasiparticle spectra around a single vortex in a d -wave superconductor. In the temperature region where the Ginzburg-Landau theory is valid, we find that the local density of states preserves a circular symmetry when the symmetry of the superconducting order parameter is {ital pure} d wave. It, however, exhibits a fourfold symmetry when the mixing of an s -wave component occurs. A peak with a {ital large energy gap} is found in the local density of states at the center of the vortex, which corresponds to the lowest bound state. Our results are consistent with a recent scanning tunneling microscopy experiment in a YBa{sub 2}Cu {sub 3}O{sub 7-{delta}} monocrystal. {copyright} {ital 1997} {ital The American Physical Society}

Vertex Operators of the q-Virasoro Algebra; Defining Relations, Adjoint Actions and Four Point Functions

Primary fields of the q-deformed Virasoro algebra are constructed. Commutation relations among the primary fields are studied. Adjoint actions of the deformed Virasoro current on the primary fields are represented by the shift operator Θξf(x) = f(ξx). Four point functions of the primary fields enjoy the connection formula associated with the Boltzmann weights of the fusion Andrews–Baxter–Forrester model.

NEAR CRITICAL STATES OF RANDOM DIRAC FERMIONS

Random Dirac fermions in a two-dimensional space are studied numerically. We realize them on a square lattice using the

Duality in the Azbel-Hofstadter Problem and Two-Dimensional d-Wave Superconductivity with a Magnetic Field.

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COMMENT ON: QUASIPARTICLE SPECTRA AROUND A SINGLE VORTEX IN A D-WAVE SUPERCONDUCTOR. AUTHORS' REPLY

-flux model with random hopping. The system preserves two symmetries, the time-reversal symmetry and the symmetry denoted by

Superconducting correlation in the one-dimensional t- J model with anisotropic spin interaction

{{\cal H},\gamma}=0

Delocalized states of the quantum Hall effect in the weak magnetic field

with a

Morita, Kohmoto, and Maki Reply:

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Quasi-Bound States of Two Magnons in the Spin-1/2XXZ Chain

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Quasi-bound states of two magnons in the XXZ spin chain

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