30,872 research outputs found
Weakly Supervised Learning of Objects, Attributes and Their Associations
The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-319-10605-2_31]”
Electromagnetic decays of vector mesons as derived from QCD sum rules
We apply the method of QCD sum rules in the presence of external
electromagnetic fields to the problem of the electromagnetic
decays of various vector mesons, such as , and . The induced condensates obtained previously
from the study of baryon magnetic moments are adopted, thereby ensuring the
parameter-free nature of the present calculation. Further consistency is
reinforced by invoking various QCD sum rules for the meson masses. The
numerical results on the various radiative decays agree very well with the
experimental data.Comment: To appear in Phys. Lett.
Bichromatic field generation from double-four-wave mixing in a double-electromagnetically induced transparency system
We demonstrate the double electromagnetically induced transparency
(double-EIT) and double four-wave mixing (double-FWM) based on a new scheme of
non-degenerate four-wave mixing (FWM) involving five levels of a cold 85Rb
atomic ensemble, in which the double-EIT windows are used to transmit the probe
field and enhance the third-order nonlinear susceptibility. The phase-matching
conditions for both four-wave mixings could be satisfied simultaneously. The
frequency of one component of the generated bichromatic field is less than the
other by the ground-state hyperfine splitting (3GHz). This specially designed
experimental scheme for simultaneously generating different nonlinear
wave-mixing processes is expected to find applications in quantum information
processing and cross phase modulation. Our results agree well with the
theoretical simulation.Comment: Accepted by NJ
Weak-Light, Zero to -\pi Lossless Kerr-Phase Gate in Quantum-well System via Tunneling Interference Effect
We examine a Kerr phase gate in a semiconductor quantum well structure based
on the tunnelling interference effect. We show that there exist a specific
signal field detuning, at which the absorption/amplification of the probe field
will be eliminated with the increase of the tunnelling interference.
Simultaneously, the probe field will acquire a -\pi phase shift at the exit of
the medium. We demonstrate with numerical simulations that a complete 180^\circ
phase rotation for the probe field at the exit of the medium is achieved, which
may result in many applications in information science and telecommunication
Artificial Gauge Field and Quantum Spin Hall States in a Conventional Two-dimensional Electron Gas
Based on the Born-Oppemheimer approximation, we divide total electron
Hamiltonian in a spinorbit coupled system into slow orbital motion and fast
interband transition process. We find that the fast motion induces a gauge
field on slow orbital motion, perpendicular to electron momentum, inducing a
topological phase. From this general designing principle, we present a theory
for generating artificial gauge field and topological phase in a conventional
two-dimensional electron gas embedded in parabolically graded
GaAs/InGaAs/GaAs quantum wells with antidot lattices. By tuning
the etching depth and period of antidot lattices, the band folding caused by
superimposed potential leads to formation of minibands and band inversions
between the neighboring subbands. The intersubband spin-orbit interaction opens
considerably large nontrivial minigaps and leads to many pairs of helical edge
states in these gaps.Comment: 9 pages and 4 figure
MRM-Lasso: A Sparse Multiview Feature Selection Method via Low-Rank Analysis
© 2015 IEEE. Learning about multiview data involves many applications, such as video understanding, image classification, and social media. However, when the data dimension increases dramatically, it is important but very challenging to remove redundant features in multiview feature selection. In this paper, we propose a novel feature selection algorithm, multiview rank minimization-based Lasso (MRM-Lasso), which jointly utilizes Lasso for sparse feature selection and rank minimization for learning relevant patterns across views. Instead of simply integrating multiple Lasso from view level, we focus on the performance of sample-level (sample significance) and introduce pattern-specific weights into MRM-Lasso. The weights are utilized to measure the contribution of each sample to the labels in the current view. In addition, the latent correlation across different views is successfully captured by learning a low-rank matrix consisting of pattern-specific weights. The alternating direction method of multipliers is applied to optimize the proposed MRM-Lasso. Experiments on four real-life data sets show that features selected by MRM-Lasso have better multiview classification performance than the baselines. Moreover, pattern-specific weights are demonstrated to be significant for learning about multiview data, compared with view-specific weights
Compressive Strength of Cold-Formed Steel C-shape Columns with Slotted Holes
Presented in this paper is an experimental investigation on the effect of web holes on the strength of cold-formed steel (CFS) C-shape columns. A total of 18 CFS C-shape stub columns were tested without and with web holes. The column length and web height of C-shape section were 490 mm (19 in) and 150 mm (6 in), respectively; and the lengths of the holes investigated were 74 mm (3 in), 114 mm (4.5 in) and 130 mm (5 in) whereas the width of the holes remains as 38 mm (1.5 in). It is noted that for the strength determination of uniformly compressed stiffened elements with non-circular holes AISI-S100 requires the length of the holes not to exceed 114 mm (4.5 in). The test results obtained from this investigation showed that local buckling at the column ends combining with one distortional half-wave along the column length was the predominant failure mode. Results also indicate that the presence of web holes had negligible effect on the ultimate compressive strengths for the hole dimensions considered here. A numerical investigation based on elastic buckling analysis confirmed that the elastic local buckling load is not affected by the presence of the hole while the elastic distortional buckling load decreases slightly as the increase of the length of the hole. A comparison between results of the tests and the Direct Strength Method approach (DSM) for CFS columns with holes demonstrated that the DSM design equations are valid to evaluate the strength of CFS C-shape columns with web holes
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