50 research outputs found
Analyzing covert social network foundation behind terrorism disaster
This paper addresses a method to analyze the covert social network foundation
hidden behind the terrorism disaster. It is to solve a node discovery problem,
which means to discover a node, which functions relevantly in a social network,
but escaped from monitoring on the presence and mutual relationship of nodes.
The method aims at integrating the expert investigator's prior understanding,
insight on the terrorists' social network nature derived from the complex graph
theory, and computational data processing. The social network responsible for
the 9/11 attack in 2001 is used to execute simulation experiment to evaluate
the performance of the method.Comment: 17pages, 10 figures, submitted to Int. J. Services Science
Reflective visualization and verbalization of unconscious preference
A new method is presented, that can help a person become aware of his or her
unconscious preferences, and convey them to others in the form of verbal
explanation. The method combines the concepts of reflection, visualization, and
verbalization. The method was tested in an experiment where the unconscious
preferences of the subjects for various artworks were investigated. In the
experiment, two lessons were learned. The first is that it helps the subjects
become aware of their unconscious preferences to verbalize weak preferences as
compared with strong preferences through discussion over preference diagrams.
The second is that it is effective to introduce an adjustable factor into
visualization to adapt to the differences in the subjects and to foster their
mutual understanding.Comment: This will be submitted to KES Journa
Electronic structure and spontaneous internal field around non-magnetic impurities in spin-triplet chiral p-wave superconductors
The electronic structure around an impurity in spin triplet p-wave
superconductors is studied by the Bogoliubov-de Gennes theory on a
tight-binding model, where we have chosen -wave
or -wave states which are
considered to be candidates for the pairing state in SrRuO.
We calculate the spontaneous current and the local density of states around
the impurity and discuss the difference between the two types of pairing.
We propose that it is possible to discriminate the two pairing states by
studying the spatial dependence of the magnetic field around a pair of
impurities.Comment: 4 pages, 4 figure
Anomalous Transport through the p-Wave Superconducting Channel in the 3-K Phase of Sr2RuO4
Using micro fabrication techniques, we extracted individual channels of
3-Kelvin (3-K) phase superconductivity in Sr2RuO4-Ru eutectic systems and
confirmed odd-parity superconductivity in the 3-K phase, similar to pure
Sr2RuO4. Unusual hysteresis in the differential resistance-current and
voltage-current characteristics observed below 2 K indicates the internal
degrees of freedom of the superconducting state. A possible origin of the
hysteresis is current-induced chiral-domain-wall motion due to the chiral
p-wave state.Comment: 4 pages, 5 figures, accepted for publication in Phys. Rev. Let
Edge states of SrRuO detected by in-plane tunneling spectroscopy
We perform tunneling spectroscopy of SrRuO searching for the edge
states peculiar to topological superconductivity. Conductance spectra obtained
on SrRuO/Au junctions fabricated using process show broad
humps indicating the successful detection of a-axis edge of 1.5K phase. Three
types of peak shape are detected: domelike peak, split peak and two-step peak.
By comparing the experiments with predictions for unconventional
superconductivity, these varieties are shown to originate from multiband chiral
p-wave symmetry with weak anisotropy of pair amplitude. The broad hump in
conductance spectrum is a direct manifestation of the edge state peculiar to
the chiral p-wave superconductivity.Comment: 7 pages and 4 figure
Theory of tunneling spectroscopy in superconducting Sr2RuO4
A theory for tunneling spectroscopy in normal metal /insulator/triplet
superconductor junction is presented. We assume two kinds of non-unitary
triplet superconducting states which are the most promising states for
SrRuO. The calculated conductance spectra showzero-bias peaks as
well as gap structures. The existences of residual components in the spectra
reflect the non-unitary properties of superconducting states.Comment: 5pages, 4figures(included), to be published in Phys.Rev.B 56, (1997
Quantum Monte Carlo study of the pairing symmetry competition in the Hubbard model
To shed light into the pairing mechanism of possible spin-triplet
superconductors (TMTSF)X and SrRuO, we study the competition among
various spin singlet and triplet pairing channels in the Hubbard model by
calculating the pairing interaction vertex using the ground state quantum Monte
Carlo technique. We model (TMTSF)X by a quarter-filled quasi-one
dimensional (quasi-1D) Hubbard model,and the band of SrRuO by
a two dimensional (2D) Hubbard model with a band filling of . For the
quasi-1D system, we find that triplet -wave pairing not only dominates over
triplet p-wave in agreement with the spin fluctuation theory, but also looks
unexpectedly competitive against d-wave. For the 2D system, although the
results suggest presence of attractive interaction in the triplet pairing
channels, the d-wave pairing interaction is found to be larger than those of
the triplet channels