13,368 research outputs found
On the Nature of X(4260)
We study the property of resonance by re-analyzing all experimental
data available, especially the cross section data. The final state
interactions of the , couple channel system are also taken
into account. A sizable coupling between the and is
found. The inclusion of the data indicates a small value of
eV.Comment: Refined analysis with new experimental data included. 13 page
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Synergy of flocculation and flotation for microalgae harvesting using aluminium electrolysis
Microalgae are often used as feedstock for renewable biofuel production and as pollutant up-takers for wastewater treatment; however, biomass harvesting still remains a challenge in field applications. In this study, electro-flocculation using aluminium electrolysis was tested as a method to collect Chlorella vulgaris. The electrolysis products were positively charged over a wide pH range below 9.5, which gave them a flocculation potential for negatively charged microalgae. As flocculants were in-situ generated and gradually released, microalgae flocs formed in a snowballing mode, resulting in the compaction of large flocs. When higher current density was applied, microalgae could be harvested more rapidly, although there was a trade-off between a higher energy use and more residual aluminium in the culture medium. Benefits of this flocculation method are two-fold: the phosphate decrease in post-harvesting could improve nutrient removal in microalgae based wastewater treatment, while the ammonium increase may favor microalgae recovery for medium recycling
Deflection of Slow Light by Magneto-Optically Controlled Atomic Media
We present a semi-classical theory for light deflection by a coherent
-type three-level atomic medium in an inhomogeneous magnetic field or
an inhomogeneous control laser. When the atomic energy levels (or the Rabi
coupling by the control laser) are position-dependent due to the Zeeman effect
by the inhomogeneous magnetic field (or the inhomogeneity of the control field
profile), the spatial dependence of the refraction index of the atomic medium
will result in an observable deflection of slow signal light when the
electromagnetically induced transparency happens to avoid medium absorption.
Our theoretical approach based on Fermat's principle in geometrical optics not
only provides a consistent explanation for the most recent experiment in a
straightforward way, but also predicts the new effects for the slow signal
light deflection by the atomic media in an inhomogeneous off-resonant control
laser field.Comment: 4 pages, 3 figure
Entangled two atoms through different couplings and the thermal noise
The entanglement of two atoms is studied when the two atoms are coupled to a
single-mode thermal field with different couplings. The different couplings of
two atoms are in favor of entanglement preparation: it not only makes the case
of absence entanglement with same coupling appear entanglement, but also
enhances the entanglement with the increasing of the relative difference of two
couplings. We also show that the diversity of coupling can improved the
critical temperature. If the optical cavity is leaky during the time evolution,
the dissipative thermal environment is benefit to produce the entanglement.Comment: 4 pages, 4 figure
Carbon-doped ZnO: A New Class of Room Temperature Dilute Magnetic Semiconductor
We report magnetism in carbon doped ZnO. Our first-principles calculations
based on density functional theory predicted that carbon substitution for
oxygen in ZnO results in a magnetic moment of 1.78 per carbon. The
theoretical prediction was confirmed experimentally. C-doped ZnO films
deposited by pulsed laser deposition with various carbon concentrations showed
ferromagnetism with Curie temperatures higher than 400 K, and the measured
magnetic moment based on the content of carbide in the films (
per carbon) is in agreement with the theoretical prediction. The magnetism is
due to bonding coupling between Zn ions and doped C atoms. Results of
magneto-resistance and abnormal Hall effect show that the doped films are
-type semiconductors with intrinsic ferromagnetism. The carbon doped ZnO
could be a promising room temperature dilute magnetic semiconductor (DMS) and
our work demonstrates possiblity of produing DMS with non-metal doping.Comment: REVtex source with 4 figures in eps forma
Entanglement detection via condition of quantum correlation
We develop a novel necessary condition of quantum correlation. It is utilized
to construct -level bipartite Bell-type inequality which is strongly
resistant to noise and requires only analyses of measurement outcomes
compared to the previous result . Remarkably, a connection between
the arbitrary high-dimensional bipartite Bell-type inequality and entanglement
witnesses is found. Through the necessary condition of quantum correlation, we
propose that the witness operators to detect truly multipartite entanglement
for a generalized Greenberger-Horne-Zeilinger (GHZ) state with two local
measurement settings and a four-qubit singlet state with three settings.
Moreover, we also propose the first robust entanglement witness to detect
four-level tripartite GHZ state with only two local measurement settings
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