26,228 research outputs found
A new metric for rotating charged Gauss-Bonnet black holes in AdS spaces
This paper presents a new metric for slowly rotating charged Gauss-Bonnet
black holes in higher dimensional anti-de Sitter spaces. Taking the angular
momentum parameter up to second order, the slowly rotating charged black
hole solutions are obtained by working directly in the action.Comment: 11 pages and accepted by Chin. Phys.
Simulation of Cavity Flow by the Lattice Boltzmann Method
A detailed analysis is presented to demonstrate the capabilities of the
lattice Boltzmann method. Thorough comparisons with other numerical solutions
for the two-dimensional, driven cavity flow show that the lattice Boltzmann
method gives accurate results over a wide range of Reynolds numbers. Studies of
errors and convergence rates are carried out. Compressibility effects are
quantified for different maximum velocities, and parameter ranges are found for
stable simulations. The paper's objective is to stimulate further work using
this relatively new approach for applied engineering problems in transport
phenomena utilizing parallel computers.Comment: Submitted to J. Comput. Physics, late
On the structure of the scalar mesons and
We investigate the structure of the scalar mesons and
within realistic meson-exchange models of the and
interactions. Starting from a modified version of the J\"ulich model for
scattering we perform an analysis of the pole structure of the
resulting scattering amplitude and find, in contrast to existing models, a
somewhat large mass for the ( MeV,
MeV). It is shown that our model provides a description of
data comparable in quality with those of
alternative models. Furthermore, the formalism developed for the
system is consistently extended to the interaction leading to a
description of the as a dynamically generated threshold effect
(which is therefore neither a conventional state nor a
bound state). Exploring the corresponding pole position the
is found to be rather broad ( MeV,
MeV). The experimentally observed smaller width results from the influence of
the nearby threshold on this pole.Comment: 25 pages, 15 Postscript figure
Vector magnetic field sensing by single nitrogen vacancy center in diamond
In this Letter, we proposed and experimentally demonstrated a method to
detect vector magnetic field with a single nitrogen vacancy (NV) center in
diamond. The magnetic field in parallel with the axis of the NV center can be
obtained by detecting the electron Zeeman shift, while the Larmor precession of
an ancillary nuclear spin close to the NV center can be used to measure the
field perpendicular to the axis. Experimentally, both the Zeeman shift and
Larmor precession can be measured through the fluorescence from the NV center.
By applying additional calibrated magnetic fields, complete information of the
vector magnetic field can be achieved with such a method. This vector magnetic
field detection method is insensitive to temperature fluctuation and it can be
applied to nanoscale magnetic measurement.Comment: 5 pages, 5 figure
Nonclassicality of quantum excitation of classical coherent field in photon loss channel
We investigate the nonclassicality of photon-added coherent states in the
photon loss channel by exploring the entanglement potential and negative Wigner
distribution. The total negative probability defined by the absolute value of
the integral of the Wigner function over the negative distribution region
reduces with the increase of decay time. The total negative probability and the
entanglement potential of pure photon-added coherent states exhibit the similar
dependence on the beam intensity. The reduce of the total negative probability
is consistent with the behavior of entanglement potential for the dissipative
single-photon-added coherent state at short decay times.Comment: 5 pages, 5 figures, RevTex4, submitte
Linear optical quantum computation with imperfect entangled photon-pair sources and inefficient non-photon-number-resolving detectors
We propose a scheme for efficient cluster state quantum computation by using
imperfect polarization-entangled photon-pair sources, linear optical elements
and inefficient non-photon-number-resolving detectors. The efficiency threshold
for loss tolerance in our scheme requires the product of source and detector
efficiencies should be >1/2 - the best known figure. This figure applies to
uncorrelated loss. We further find that the loss threshold is unaffected by
correlated loss in the photon pair source. Our approach sheds new light on
efficient linear optical quantum computation with imperfect experimental
conditions.Comment: 5 pages, 2 figure
Strangeness spin, magnetic moment and strangeness configurations of the proton
The implications of the empirical signatures for the positivity of the
strangeness magnetic moment , and the negativity of the strangeness
contribution to the proton spin , on the possible
configurations of five quarks in the proton are analyzed. The empirical signs
for the values of these two observables can only be obtained in configurations
where the system is orbitally excited and the quark is in the
ground state. The configurations, in which the is orbitally excited,
which include the conventional congfiguration, with the
exception of that, in which the component has spin 2, yield negative
values for . Here the strangeness spin , the strangeness
magnetic moment and the axial coupling constant are calculated
for all possible configurations of the component of the proton. In
the configuration with flavor-spin symmetry, which is
likely to have the lowest energy, is positive and .Comment: 17 page
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