arXiv subjects
Publications and source records attributed to O. Narikiyo.
The inelastic neutron scattering spectrum in cuprate superconductors is discussed on the basis of the itinerant-localized duality model for strongly correlated electrons. In Appendix the consistency with recent rigorous theoretical result on ARPES is discussed.
How the fluctuation-exchange (FLEX) approximation and the Fermi-liquid theory fail to explain the anomalous behavior of the Hall coefficient in the normal state of high-Tc superconductors is clarified.
Ward identities for Cooper pairs are derived. These give consistent description of electronic curent vertex and thermal current vertex.
We propose a principle of superposition to describe protein-folding nuclei and explain an evolutional conservation of a field pattern specifying native-state structure.
The exponent puzzle of the Anderson-Mott transition is discussed on the basis of a duality model for strongly correlated electrons.
Evolutionally conserved quantity that specifies folding nuclei is pursued by a case study for a small protein (PDB code: 1ten). First it is demonstrated that the sequences of amino acids at folding nuclei are not conserved. Then 3D (3-dimensional) information of the structure is considered and it is found that a 3D hydrophobicity profile is essential to specify the folding nuclei and evolutionally conserved. This profile is maintained by the interaction, including entropic effect, among amino acids realized in the native state structure. Experimentally observed phi-value is correlated to this 3D hydrophobicity profile after taking into account the effect of the contact distance in amino-acid sequence.
Superconductor-Metal-Insulator crossover in disordered thin films is discussed on the basis of a random junction-network model.
In order to understand the non-Fermi-liquid behavior of MnSi under pressure we propose a scenario on the basis of the multispiral state of the magnetic moment. This state can describe the recent critical experiment of the Bragg sphere in the neutron scattering which is the key ingredient of the non-Fermi-liquid behavior.
By calculating the non-equilibrium parameter of the probability distribution function and the singularity spectrum of multifractal we have quantified the dynamical heterogeneity in strongly correlated many-body systems.
On the basis of the lattice Boltzmann method we have done a numerical experiment of a forced turbulence in real space and time. Our new findings are summarized into two points. First in the analysis of the mean-field behavior of the velocity field using the exit-time statistics we have verified Kolmogorov's scaling and Taylor's hypothesis for the first time in the simulation for the Navier-Stokes equation. Second in the analysis of the intermittent velocity fluctuations using a non-equilibrium probability distribution function and the wavelet denoising we have clarified that the coherent vortices sustain the power-law velocity correlation in the non-equilibrium state.
We have shown that the epsilon-entropy determined from the time-series of the velocity fluctuation in a forced turbulence simulated by the lattice Boltzmann method obeys the Kolmogorov scaling.
The dynamical heterogeneity in supercooled liquids measured by a molecular dynamics simulation has been quantified on the basis of the multifractal formalism. The singularity spectrum becomes broader as the glass transition is approached. This behavior is similar to that observed in the case of the Anderson-localization transition.
The distribution of the fractal dimension of the two-dimensional Ising model at the critical temperature measured by the Monte-Carlo simulation is discussed. At small spatio-temporal scales it exhibits a multifractal behavior and is well fitted by a non-Gaussian distribution derived from the Rényi or Tsallis entropy.
The Hall angle in the doped V_2O_3 is discussed on the basis of an extended Ginzburg-Landau theory of spin fluctuations. A spinon-like collective transport process beyond the ordinary quasiparticle transport theory is necessary to understand the experiment. At the same time a criticism of a quasiparticle transport theory on the basis of the fluctuation exchange (FLEX) approximation is made.
I point out that a magnetotransport theory on the basis of the fluctuation exchange (FLEX) approximation, which is proposed in order to explain anomalous transport properties in the normal state of high-$T_{\rm c}$ cuprate superconductors, is not compatible with the Fermi liquid theory and that the anomaly obtained there ascribes to the inconsistency of the approximation.
Recent experiments on the spin-spin relaxation time in high-Tc cuprate superconductors are discussed on the basis of the BCS-RPA theory.
Theories of the magnetotransport, based on the quasipartricle of the Fermi-liquid, in the normal state of high-Tc cuprate superconductors, are critically examined and the necessity of the collective transport theory beyond the quasiparticle is discussed.
We have combined the dynamical mean field theories of the Mott transition and the spin glass in infinite dimensions and derived a metallic spin-glass state from a random spin-fermion model.