arXiv subjects

N. Kawakami

Publications and source records attributed to N. Kawakami.

43 records · Page 3Linked to original sources

arXiv1995

Transport coefficients, effective charge and mass for multicomponent systems with fractional exclusion statistics

Transport properties of the multicomponent quantum many-body systems obeying Haldane's fractional exclusion statistics are studied in one dimension. By computing the finite-size spectrum under twisted boundary conditions, we explicitly express the conductivity and the conductance in terms of statistical interactions. Through this analysis, the effective charge and effective mass for collective excitations are determined. We apply the results for $1/r^2$ quantum systems as well as for correlated electron systems.

cond-mat↗

arXiv1994

Bosonization approach to the one-dimensional Kondo lattice model

The one-dimensional Kondo lattice model is investigated by using bosonization techniques and conformal field theory. In the half-filled band, the charge and spin gaps open for the anti-ferromagnetic Kondo coupling. Away from half-filling, the paramagnetic metallic state is characterized by the fixed point of Tomonaga-Luttinger liquid with the {\it large} Fermi surface in accordance with known results. It is suggested that as the electron density approaches half-filling, both of spin and charge susceptibilities may show a divergence property.

cond-mat↗

arXiv1994

Microscopic Calculations of the Finite-Size Spectrum in the Kondo Problem

The finite-size spectrum in the Kondo problem is obtained from the Bethe-ansatz solution of the exactly solved models. We investigate the Anderson model, the highly correlated SU($ν$) Anderson model and the {\it s-d} exchange model. For all these models we find that the spectra exhibit the properties characteristic of the Fermi liquid fixed point, and hence our microscopic calculations are in accordance with the results obtained by boundary conformal field theory with current algebra symmetry.

cond-mat↗

arXiv1994

Eigenfunctions for SU(N) particles with 1/r^2 interaction in harmonic confinement

We find a set of the exact eigenfunctions which provide the energy spectrum for the quantum $N$-body Calogero-Sutherland model for fermions or bosons with SU($ν$) spin degrees of freedom moving in a harmonic confinement potential. The eigenfunctions are explicitly constructed as a simple product of the Jastrow wave function for the ground state and the Hermite polynomials introduced to generate the excited states. The corresponding energy spectrum is given by a sum of the correlated ground-state energy and of the excited-state energy for SU($ν$) free particles in a harmonic well.

cond-mat↗

arXiv1993

Comment on "Microscopic Theory of Periodic Conductances in Narrow Channels"

In a recent letter Johnson and Payne (JP) have studied the effect of the electron interaction on the periodic conductance oscillations in narrow channels based on an exactly solvable model. In this Comment we discuss the exchange-correlation effect on JP's model using a solvable electron model. We wish to point out that when the interaction strength becomes rather small, there may appear two periods in the conductance oscillations due to the exchange effect.

cond-mat↗

arXiv1993

Confined quantum systems in one dimension and conductance oscillations in narrow channels

An exactly solvable electron model of a confined system with inverse-square interaction is presented. The ground state is given by the Jastrow-product wavefunction of power-law form. We discuss the results in connection with conductance oscillations observed in semiconductor nanostructures, for which single-electron charging effects play a crucial role. Due to the internal spin degrees of freedom, there appear two independent periods of the conductance oscillations in very narrow channels even at zero temperature.

cond-mat↗

arXiv1993

Renormalized Harmonic-Oscillator Description of Confined Electron Systems with Inverse-Square Interaction

An integrable model for SU($ν$) electrons with inverse-square interaction is studied for the system with confining harmonic potential. We develop a new description of the spectrum based on the {\it renormalized harmonic-oscillators} which incorporate interaction effects via the repulsion of energy levels. This approach enables a systematic treatment of the excitation spectrum as well as the ground-state quantities.

cond-mat↗