Testing quantum entanglement with local measurement

We propose to detect quantum entanglement by a condition of local measurments. We find that this condition can detect efficiently the pure entangled states for both discrete and continuous variable systems. It does not depend on interference of decoherence from noise and detection loss in some systems, which allows a loophole-free test in real experiments. In particular, it is a necessary condition for the violation of some generalized Bell inequalities.Comment: 5 page

Geometrical structure effect on localization length of carbon nanotubes

The localization length and density of states of carbon nanotubes are evaluated within the tight-binding approximation. By comparison with the corresponding results for the square lattice tubes, it is found that the hexagonal structure affects strongly the behaviors of the density of states and localization lengths of carbon nanotubes.Comment: 7 pages, 4 figures, revised version to appear in Chin. Phys. Lett. The title is changed. Some arguments are adde

Bosonization of One-Dimensional Exclusons and Characterization of Luttinger Liquids

We achieve a bosonization of one-dimensional ideal gas of exclusion statistics $\lambda$ at low temperatures, resulting in a new variant of $c=1$ conformal field theory with compactified radius $R=\sqrt{1/\lambda}$. These ideal excluson gases exactly reproduce the low-$T$ critical properties of Luttinger liquids, so they can be used to characterize the fixed points of the latter. Generalized ideal gases with mutual statistics and non-ideal gases with Luttinger-type interactions have also similar behavior, controlled by an effective statistics varying in a fixed-point line.Comment: 13 pages, revte

Possible nodeless superconductivity in the noncentrosymmetric superconductor Mg_(12-delta)Ir_19B_16

We measured the resistivity, diamagnetization, and low-temperature specific heat of the newly discovered noncentrosymmetric superconductor Mg_(12-delta)Ir_19B_16. The temperature dependence of specific heat is consistent with the model of an isotropic s-wave gap with value Delta_0 = 0.94 meV for the sample Tc = 5.7 K, and the ratio Delta_0/k_BTc = 1.91 indicates a slightly moderate coupling for the superconductivity. The correlations among the normal state Sommerfeld constant gamma_n, the slope -dHc2(T)/dT near Tc, and the condensation energy Ec are all consistent with the slightly moderate coupling picture. Based on the data of phonon contribution, Tc and the McMillan formula, we obtained an electron-phonon coupling strength lambda_(e-ph) = 0.66, which suggests that the superconductivity here is induced by the electron-phonon coupling.Comment: 6 pages, 7 figure

Variation of particle number size distributions and chemical compositions at the urban and downwind regional sites in the Pearl River Delta during summertime pollution episodes

In order to characterize the features of particulate pollution in the Pearl River Delta (PRD) in the summer, continuous measurements of particle number size distributions and chemical compositions were simultaneously performed at Guangzhou urban site (GZ) and Back-garden downwind regional site (BG) in July 2006. Particle number concentration from 20 nm to 10 μm at BG was (1.7±0.8)×10<sup>4</sup> cm<sup>−3</sup>, about 40% lower than that at GZ, (2.9±1.1)×10<sup>4</sup> cm<sup>−3</sup>. The total particle volume concentration at BG was 94±34 μm<sup>3</sup> cm<sup>−3</sup>, similar to that at GZ, 96±43 μm<sup>3</sup> cm<sup>−3</sup>. More 20–100 nm particles, significantly affected by the traffic emissions, were observed at GZ, while 100–660 nm particle number concentrations were similar at both sites as they are more regional. PM<sub>2.5</sub> values were similar at GZ (69±43 μg m<sup>−3</sup>) and BG (69±58 μg m<sup>−3</sup>) with <i>R</i><sup>2</sup> of 0.71 for the daily average PM<sub>2.5</sub> at these two sites, indicating the fine particulate pollution in the PRD region to be regional. Two kinds of pollution episodes, the accumulation pollution episode and the regional transport pollution episode, were observed. Fine particles over 100 nm dominated both number and volume concentrations of total particles during the late periods of these pollution episodes. Accumulation and secondary transformation are the main reasons for the nighttime accumulation pollution episode. SO<sub>4</sub><sup>2−</sup>, NO<sub>3</sub><sup>−</sup> accounted for about 60% in 100–660 nm particle mass and PM<sub>2.5</sub> increase. When south or southeast wind prevailed in the PRD region, regional transport of pollutants took place. Regional transport contributed about 30% to fine particulate pollution at BG during a regional transport case. Secondary transformation played an important role during regional transport, causing higher increase rates of secondary ions in PM<sub>1.0</sub> than other species and shifting the peaks of sulfate and ammonium mass size distributions to larger sizes. SO<sub>4</sub><sup>2−</sup>, NO<sub>3</sub><sup>−</sup>, and NH<sub>4</sub><sup>+</sup> accounted for about 70% and 40% of PM<sub>1.0</sub> and PM<sub>2.5</sub>, respectively