39,425 research outputs found

    Correlation-induced resonances and population switching in a quantum dot coulomb valley

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    Strong correlation effects on electron transport through a spinless quantum dot are considered. When two single-particle levels in the quantum dot are degenerate, a conserved pseudospin degree of freedom appears for general tunneling matrix elements between the quantum dot and leads. Local fluctuations of the pseudospin in the quantum dot give rise to a pair of asymmetric conductance peaks near the center of a Coulomb valley. An exact relation to the population switching is provided.Comment: Fig. 4 and some technical details removed. To appear in PR

    Parity-violating Ο€NN\pi NN coupling constant from the flavor-conserving effective weak chiral Lagrangian

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    We investigate the parity-violating pion-nucleon-nucleon coupling constant hΟ€NN1h^1_{\pi NN}, based on the chiral quark-soliton model. We employ an effective weak Hamiltonian that takes into account the next-to-leading order corrections from QCD to the weak interactions at the quark level. Using the gradient expansion, we derive the leading-order effective weak chiral Lagrangian with the low-energy constants determined. The effective weak chiral Lagrangian is incorporated in the chiral quark-soliton model to calculate the parity-violating Ο€NN\pi NN constant hΟ€NN1h^1_{\pi NN}. We obtain a value of about 10βˆ’710^{-7} at the leading order. The corrections from the next-to-leading order reduce the leading order result by about 20~\%.Comment: 12 page

    Generalized Video Deblurring for Dynamic Scenes

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    Several state-of-the-art video deblurring methods are based on a strong assumption that the captured scenes are static. These methods fail to deblur blurry videos in dynamic scenes. We propose a video deblurring method to deal with general blurs inherent in dynamic scenes, contrary to other methods. To handle locally varying and general blurs caused by various sources, such as camera shake, moving objects, and depth variation in a scene, we approximate pixel-wise kernel with bidirectional optical flows. Therefore, we propose a single energy model that simultaneously estimates optical flows and latent frames to solve our deblurring problem. We also provide a framework and efficient solvers to optimize the energy model. By minimizing the proposed energy function, we achieve significant improvements in removing blurs and estimating accurate optical flows in blurry frames. Extensive experimental results demonstrate the superiority of the proposed method in real and challenging videos that state-of-the-art methods fail in either deblurring or optical flow estimation.Comment: CVPR 2015 ora

    Air transparent soundproof window

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    A soundproof window or wall which is transparent to airflow is presented. The design is based on two wave theories of diffraction and acoustic metamaterials. It consists of a three-dimensional array of strong diffraction-type resonators with many holes centered at each individual resonator. The acoustic performance levels of two soundproof windows with air holes of 20mm20mm and 50mm50mm diameters were measured. Sound waves of 80dB in the frequency range of 400βˆ’5,000Hz400 - 5,000Hz were applied to the windows. It was observed that the sound level was reduced by about 30βˆ’3530 - 35dB in the above frequency range with the 20mm20mm window and by about 20βˆ’3520 - 35dB in the frequency range of 700βˆ’2,200Hz700 - 2,200Hz with the 50mm50mm window. It is an extraordinary acoustic anti-transmission. The geometric factors which produced the effective negative modulus were obtained.Comment: 4 pages, 6 figures, 1 tabl
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