27,176 research outputs found
Hyper-elliptic Nambu flow associated with integrable maps
We study hyper-elliptic Nambu flows associated with some dimensional maps
and show that discrete integrable systems can be reproduced as flows of this
class.Comment: 13 page
Chirality Selection in Open Flow Systems and in Polymerization
As an attempt to understand the homochirality of organic molecules in life, a
chemical reaction model is proposed where the production of chiral monomers
from achiral substrate is catalyzed by the polymers of the same enatiomeric
type. This system has to be open because in a closed system the enhanced
production of chiral monomers by enzymes is compensated by the associated
enhancement in back reaction, and the chiral symmetry is conserved. Open flow
without cross inhibition is shown to lead to the chirality selection in a
general model. In polymerization, the influx of substrate from the ambience and
the efflux of chiral products for purposes other than the catalyst production
make the system necessarily open. The chiral symmetry is found to be broken if
the influx of substrate lies within a finite interval. As the efficiency of the
enzyme increases, the maximum value of the enantiomeric excess approaches unity
so that the chirality selection becomes complete.Comment: 8 pages, 4 figure
Coupled ion - nanomechanical systems
We study ions in a nanotrap, where the electrodes are nanomechanical
resonantors. The ions play the role of a quantum optical system which acts as a
probe and control, and allows entanglement with or between nanomechanical
resonators.Comment: 4 pages, 2 figures, submitted for publicatio
Physics Beyond SM at RHIC with Polarized Protons
The capabilities of RHIC with polarized protons to test the Lorentz structure
of electroweak interactions and also the properties of MSSM Higgs, should it be
discovered, are discussed.Comment: Report to the 14th International Symposium on Spin Physics, October
16-21, 2000, RCNP, Osaka University, Osaka, Japan. To be published in the
Proceedings, 6 page
Electronic States of Graphene Nanoribbons
We study the electronic states of narrow graphene ribbons (``nanoribbons'')
with zigzag and armchair edges. The finite width of these systems breaks the
spectrum into an infinite set of bands, which we demonstrate can be
quantitatively understood using the Dirac equation with appropriate boundary
conditions. For the zigzag nanoribbon we demonstrate that the boundary
condition allows a particle- and a hole-like band with evanescent wavefunctions
confined to the surfaces, which continuously turn into the well-known zero
energy surface states as the width gets large. For armchair edges, we show that
the boundary condition leads to admixing of valley states, and the band
structure is metallic when the width of the sample in lattice constant units is
divisible by 3, and insulating otherwise. A comparison of the wavefunctions and
energies from tight-binding calculations and solutions of the Dirac equations
yields quantitative agreement for all but the narrowest ribbons.Comment: 5 pages, 6 figure
Spontaneous Circulation in Ground-State Spinor Dipolar Bose-Einstein Condensates
We report on a study of the spin-1 ferromagnetic Bose-Einstein condensate
with magnetic dipole-dipole interactions. By solving the non-local
Gross-Pitaevskii equations for this system, we find three ground-state phases.
Moreover, we show that a substantial orbital angular momentum accompanied by
chiral symmetry breaking emerges spontaneously in a certain parameter regime.
We predict that all these phases can be observed in the spin-1 Rb
condensate by changing the number of atoms or the trap frequency.Comment: final versio
Devil's staircase of incompressible electron states in a nanotube
It is shown that a periodic potential applied to a nanotube can lock
electrons into incompressible states. Depending on whether electrons are weakly
or tightly bound to the potential, excitation gaps open up either due to the
Bragg diffraction enhanced by the Tomonaga - Luttinger correlations, or via
pinning of the Wigner crystal. Incompressible states can be detected in a
Thouless pump setup, in which a slowly moving periodic potential induces
quantized current, with a possibility to pump on average a fraction of an
electron per cycle as a result of interactions.Comment: 4 pages, 1 figure, published versio
Chiral Crystal Growth under Grinding
To study the establishment of homochirality observed in the crystal growth
experiment of chiral molecules from a solution under grinding, we extend the
lattice gas model of crystal growth as follows. A lattice site can be occupied
by a chiral molecule in R or S form, or can be empty. Molecules form
homoclusters by nearest neighbor bonds. They change their chirality if they are
isolated monomers in the solution. Grinding is incorporated by cutting and
shafling the system randomly. It is shown that Ostwald ripening without
grinding is extremely slow to select chirality, if possible. Grinding alone
also cannot achieve chirality selection. For the accomplishment of
homochirality, we need an enhanced chirality change on crystalline surface.
With this "autocatalytic effect" and the recycling of monomers due to rinding,
an exponential increase of crystal enantiomeric excess to homochiral state is
realized.Comment: 10 pages, 5 figure
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