1,197 research outputs found
Dynamics of topological solitons in two-dimensional ferromagnets
Dynamical topological solitons are studied in classical two-dimensional
Heisenberg easy-axis ferromagnets. The properties of such solitons are treated
both analytically in the continuum limit and numerically by spin dynamics
simulations of the discrete system. Excitation of internal mode causes orbital
motion. This is confirmed by simulations.Comment: LaTeX, 15 pages, 6 figure
Enhanced insight on the effects of boulders on bedload transport
River morphodynamics and sediment transportMechanics of sediment transpor
Magnon dispersion and thermodynamics in CsNiF_3
We present an accurate transfer matrix renormalization group calculation of
the thermodynamics in a quantum spin-1 planar ferromagnetic chain. We also
calculate the field dependence of the magnon gap and confirm the accuracy of
the magnon dispersion derived earlier through an 1/n expansion. We are thus
able to examine the validity of a number of previous calculations and further
analyze a wide range of experiments on CsNiF_3 concerning the magnon
dispersion, magnetization, susceptibility, and specific heat. Although it is
not possible to account for all data with a single set of parameters, the
overall qualitative agreement is good and the remaining discrepancies may
reflect departure from ideal quasi-one-dimensional model behavior. Finally, we
present some indirect evidence to the effect that the popular interpretation of
the excess specific heat in terms of sine-Gordon solitons may not be
appropriate.Comment: 9 pages 10 figure
Maxwell--Chern-Simons gauged non-relativistic O(3) model with self-dual vortices
A non-relativistic version of the 2+1 dimensional gauged Chern-Simons O(3)
sigma model, augmented by a Maxwell term, is presented and shown to support
topologically stable static self-dual vortices. Exactly like their counterparts
of the ungauged model, these vortices are shown to exhibit Hall behaviour in
their dynamics.Comment: 12 pages, LateX, to appear in Mod. Phys. Lett. 199
Solitary Waves of Planar Ferromagnets and the Breakdown of the Spin-Polarized Quantum Hall Effect
A branch of uniformly-propagating solitary waves of planar ferromagnets is
identified. The energy dispersion and structures of the solitary waves are
determined for an isotropic ferromagnet as functions of a conserved momentum.
With increasing momentum, their structure undergoes a transition from a form
ressembling a droplet of spin-waves to a Skyrmion/anti-Skyrmion pair. An
instability to the formation of these solitary waves is shown to provide a
mechanism for the electric field-induced breakdown of the spin-polarized
quantum Hall effect.Comment: 5 pages, 3 eps-figures, revtex with epsf.tex and multicol.st
Vortex Pull by an External Current
In the context of a dynamical Ginzburg-Landau model it is shown numerically
that under the influence of a homogeneous external current J the vortex drifts
against the current with velocity in agreement to earlier analytical
predictions. In the presence of dissipation the vortex undergoes skew
deflection at an angle with respect to the
external current. It is shown analytically and verified numerically that the
angle and the speed of the vortex are linked through a simple
mathematical relation.Comment: 19 pages, LATEX, 6 Postscript figures included in separate compressed
fil
Green function Retrieval and Time-reversal in a Disordered World
We apply the theory of multiple wave scattering to two contemporary, related
topics: imaging with diffuse correlations and stability of time-reversal of
diffuse waves, using equipartition, coherent backscattering and frequency
speckles as fundamental concepts.Comment: 1 figur
Enhanced statistical stability in coherent interferometric imaging
http://iopscience.iop.org/0266-5611/International audienc
Extracellular Matrix Oxidised by the Granulocyte Oxidants Hypochlorous and Hypobromous Acid Reduces Lung Fibroblast Adhesion and Proliferation In Vitro.
Chronic airway inflammation and oxidative stress play crucial roles in the pathogenesis of chronic inflammatory lung diseases, with airway inflammation being a key driving mechanism of oxidative stress in the lungs. Inflammatory responses in the lungs activate neutrophils and/or eosinophils, leading to the generation of hypohalous acids (HOX). These HOX oxidants can damage the extracellular matrix (ECM) structure and may influence cell-ECM interactions. The ECM of the lung provides structural, mechanical, and biochemical support for cells and determines the airway structure. One of the critical cells in chronic respiratory disease is the fibroblast. Thus, we hypothesised that primary human lung fibroblasts (PHLF) exposed to an oxidised cell-derived ECM will result in functional changes to the PHLF. Here, we show that PHLF adhesion, proliferation, and inflammatory cytokine secretion is affected by exposure to HOX-induced oxidisation of the cell-derived ECM. Furthermore, we investigated the impact on fibroblast function from the presence of haloamines in the ECM. Haloamines are chemical by-products of HOX and, like the HOX, haloamines can also modify the ECM. In conclusion, this study revealed that oxidising the cell-derived ECM might contribute to functional changes in PHLF, a key mechanism behind the pathogenesis of inflammatory lung diseases
Search for the Nondimerized Quantum Nematic Phase in the Spin-1 Chain
Chubukov's proposal concerning the possibility of a nondimerized quantum
nematic phase in the ground-state phase diagram of the bilinear-biquadratic
spin-1 chain is studied numerically. Our results do not support the existence
of this phase, but they rather indicate a direct transition from the
ferromagnetic into the dimerized phase.Comment: REVTEX, 14 pages +8 PostScript figure
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