5,211 research outputs found
Stochastic Rotation Dynamics for Nematic Liquid Crystals
We introduce a new mesoscopic model for nematic liquid crystals (LCs). We
extend the particle-based stochastic rotation dynamics method, which reproduces
the Navier-Stokes equation, to anisotropic fluids by including a simplified
Ericksen-Leslie formulation of nematodynamics. We verify the applicability of
this hybrid model by studying the equilibrium isotropic-nematic phase
transition and nonequilibrium problems, such as the dynamics of topological
defects, and the rheology of sheared LCs. Our simulation results show that this
hybrid model captures many essential aspects of LC physics at the mesoscopic
scale, while preserving microscopic thermal fluctuations
Squeezing and entanglement of matter-wave gap solitons
We study quantum squeezing and entanglement of gap solitons in a
Bose-Einstein condensate loaded into a one-dimensional optical lattice. By
employing a linearized quantum theory we find that quantum noise squeezing of
gap solitons, produced during their evolution, is enhanced compared with the
atomic solitons in a lattice-free case due to intra-soliton structure of
quantum correlations induced by the Bragg scattering in the periodic potential.
We also show that nonlinear interaction of gap solitons in dynamically stable
bound states can produce strong soliton entanglement.Comment: 4 pages, 5 figure
QCD Multipole Expansion and Hadronic Transitions in Heavy Quarkonium Systems
We review the developments of QCD multipole expansion and its applications to
hadronic transitions and some radiative decays of heavy quarkonia. Theoretical
predictions are compsred with updated experimental results.Comment: 23 pages, 7 figures. Some typos corrected, and 3 references adde
Multiple Equilibria in a Single-Column Model of the Tropical Atmosphere
A single-column model run under the weak temperature gradient approximation,
a parameterization of large-scale dynamics appropriate for the tropical
atmosphere, is shown to have multiple stable equilibria. Under conditions
permitting persistent deep convection, the model has a statistically steady
state in which such convection occurs, as well as an extremely dry state in
which convection does not occur. Which state is reached depends on the initial
moisture profile.Comment: Submitted to Geophysical Research Letter
Rolling of asymmetric disks on an inclined plane
In a recent papers, Turner and Turner (2010 {\em Am. J. Phys.} {\bf 78}
905-7) and Jensen (2011 {\em Eur. J. Phys.} {\bf 32} 389-397) analysed the
motion of asymmetric rolling rigid bodies on a horizontal plane. These papers
addressed the common misconception that the instantaneous point of contact of
the rolling body with the plane can be used to evaluate the angular momentum
and the torque in the equation of motion
. To obtain the correct equation of motion,
the "phantom torque" or various rules that depend on the motion of the point
about which and are evaluated were discussed. In
this paper, I consider asymmetric disks rolling down an inclined plane and
describe the most basic way of obtaining the correct equation of motion; that
is, to choose the point about which and are
evaluated that is stationary in an inertial frame
Prevention and control of Zika fever as a mosquito-borne and sexually transmitted disease
The ongoing Zika virus (ZIKV) epidemic poses a major global public health
emergency. It is known that ZIKV is spread by \textit{Aedes} mosquitoes, recent
studies show that ZIKV can also be transmitted via sexual contact and cases of
sexually transmitted ZIKV have been confirmed in the U.S., France, and Italy.
How sexual transmission affects the spread and control of ZIKV infection is not
well-understood. We presented a mathematical model to investigate the impact of
mosquito-borne and sexual transmission on spread and control of ZIKV and used
the model to fit the ZIKV data in Brazil, Colombia, and El Salvador. Based on
the estimated parameter values, we calculated the median and confidence
interval of the basic reproduction number R0=2.055 (95% CI: 0.523-6.300), in
which the distribution of the percentage of contribution by sexual transmission
is 3.044 (95% CI: 0.123-45.73). Our study indicates that R0 is most sensitive
to the biting rate and mortality rate of mosquitoes while sexual transmission
increases the risk of infection and epidemic size and prolongs the outbreak. In
order to prevent and control the transmission of ZIKV, it must be treated as
not only a mosquito-borne disease but also a sexually transmitted disease
Anomalous gauge couplings of the Higgs boson at high energy photon colliders
We study the sensitivity of testing the anomalous gauge couplings 's
of the Higgs boson in the formulation of linearly realized gauge symmetry via
the processes and at polarized and
unpolarized photon colliders based on linear colliders of
c.m.~energies 500 GeV, 1 TeV, and 3 TeV. Signals beyond the standard model (SM)
and SM backgrounds are carefully studied. We propose certain kinematic cuts to
suppress the standard model backgrounds. For an integrated luminosity of 1
ab, we show that (a) can provide a test of
to the sensitivity of
TeV at a 500 GeV ILC, and TeV at a 1 TeV ILC and a 3
TeV CLIC, and (b) at a 3 TeV CLIC can test all the
anomalous couplings 's to the sensitivity of
TeV.Comment: 30 pages, 17 figure
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