541 research outputs found
Effects of the Lattice Discreteness on a Soliton in the Su-Schrieffer-Heeger Model
In this paper we analytically study the effects of the lattice discreteness
on the electron band in the SSH model. We propose a modified version of the TLM
model which is derived from the SSH model using a continuum approximation. When
a soliton is induced in the electron-lattice system, the electron scattering
states both at the bottom of the valence band and the top of the conduction
band are attracted to the soliton. This attractive force induces weakly
localized electronic states at the band edges. Using the modified version of
the TLM model, we have succeeded in obtaining analytical solutions of the
weakly localized states and the extended states near the bottom of the valence
band and the top of the conduction band. This band structure does not modify
the order parameters. Our result coincides well with numerical simulation
works.Comment: to be appear in J.Phys.Soc.Jpn. Figures should be requested to the
author. They will be sent by the conventional airmai
The Relation of Traffic Flow in One-lane to the Sensitivity in the Stochastic Optimal Velocity Model
Quantum Nernst effect in a bismuth single crystal
We report a theoretical calculation explaining the quantum Nernst effect
observed experimentally in a bismuth single crystal. Generalizing the
edge-current picture in two dimensions, we show that the peaks of the Nernst
coefficient survive in three dimensions due to a van Hove singularity. We also
evaluate the phonon-drag effect on the Nernst coefficient numerically. Our
result agrees with the experimental result for a bismuth single crystal.Comment: 4 pages, 4 figures, to be published in Proceedings of ISQM-Tokyo '0
HETE Observations of the Gamma-Ray Burst GRB030329: Evidence for an Underlying Soft X-ray Component
An exceptionally intense gamma-ray burst, GRB030329, was detected and
localized by the instruments on board the High Energy Transient Explorer
satellite (HETE) at 11:37:14 UT on 29 March 2003. The burst consisted of two
\~10s pulses of roughly equal brightness and an X-ray tail lasting >100s. The
energy fluence in the 30-400 keV energy band was 1.08e-4 erg/cm2, making
GRB030329 one of the brightest GRBs ever detected. Communication of a 2 arcmin
error box 73 minutes after the burst allowed the rapid detection of a
counterpart in the optical, X-ray, radio and the ensuing discovery of a
supernova with most unusual characteristics. Analyses of the burst lightcurves
reveal the presence of a distinct, bright, soft X-ray component underlying the
main GRB: the 2-10 keV fluence of this component is ~7e-6 erg/cm2. The main
pulses of GRB030329 were preceded by two soft, faint, non-thermal bumps. We
present details of the HETE observations of GRB030329.Comment: 22 pages, 5 figures, to be published in ApJ 617, no. 2 (10 December
2004). Referee comments have been incorporated; results of improved spectral
analysis are include
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