38,391 research outputs found
Numerical Computation of Thermoelectric and Thermomagnetic Effects
Phenomenological equations describing the Seebeck, Hall, Nernst, Peltier,
Ettingshausen, and Righi-Leduc effects are numerically solved for the
temperature, electric current, and electrochemical potential distributions of
semiconductors under magnetic field. The results are compared to experiments.Comment: 4 pages, 7 figures. Submitted to Proceedings of XVII International
Conference on Thermoelectrics (ICT98), 1998 Nagoya, Japa
Energy diffusion in frustrated quantum spin chains exhibiting Gaussian orthogonal ensemble level statistics
Frustrated quantum spin chains with the next-nearest-neighbor (NNN)
couplings are typically deterministic many-body systems exhibiting Gaussian
orthogonal ensemble (GOE) spectral statistics. We investigate energy diffusion
for these spin chains in the presence of a periodically oscillating magnetic
field. Diffusion coefficients are found to obey the power law with respect to
both the field strength and driving frequency with its power varying depending
on the linear response and non-perturbative regimes. The widths of the linear
response and the non-perturbative regimes depend on the strength of
frustrations. We have also elucidated a mechanism for oscillation of energy
diffusion in the case of weakened frustrations.Comment: 6 pages, 6 figure
Pion Interferometry From A Relativistic Fluid With A First Order Phase Transition In CERN-SPS 158 GeV/A Pb+Pb Collisions
We investigate pion source sizes through the Yano-Koonin-Podgoretski\u{\i}
(YKP) parametrization for the Hanbury-Brown Twiss (HBT) effect in the CERN-SPS
158 GeV/A central collisions. We calculate two-particle correlation functions
numerically based on a (3+1)-dimensional relativistic hydrodynamics with a
first order phase transition and analyze the pair momentum dependence of the
HBT radii extracted from the YKP parametrization in detail. We find that even
in the case of a first order phase transition, expansion and the surface
dominant freeze-out make the source in the hydrodynamical model opaque
significantly. Consequently, the interpretation of the temporal radius
parameter as the time duration becomes unavailable for the hydrodynamical
model.Comment: 5 pages, LaTeX with six eps figures, Contribution to 'International
Workshop XXVIII on Gross Properties of Nuclei And Nuclear Excitations'.
Hirchegg, Austria, Jan 16-22, 200
Frustrated quantum-spin system on a triangle coupled with lattice vibrations - Correspondence to Longuet-Higgins et al.'s Jahn-Teller model -
We investigate the quantum three spin model
of spin on a triangle, in which spins are coupled with
lattice-vibrational modes through the exchange interaction depending on
distances between spin sites. The present model corresponds to the dynamic
Jahn-Teller system proposed by Longuet-Higgins {\it et al.},
Proc.R.Soc.A.{\bf 244},1(1958). This correspondence is revealed by using the
transformation to Nakamura-Bishop's bases proposed in Phys.Rev.Lett.{\bf
54},861(1985). Furthermore, we elucidate the relationship between the behavior
of a chiral order parameter and
that of the electronic orbital angular momentum in vibronic model: The regular oscillatory behavior of the expectation value
. The increase of the additional
anharmonicity(chaoticity) is found to yield a rapidly decaying irregular
oscillation of
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