Anatomy of Bs→PVB_s \to PV decays and effects of next-to-leading order contributions in the perturbative QCD factorization approach

In this paper, we will make systematic calculations for the branching ratios and the CP-violating asymmetries of the twenty one $\bar{B}^0_s \to PV$ decays by employing the perturbative QCD (PQCD) factorization approach. Besides the full leading-order (LO) contributions, all currently known next-to-leading order (NLO) contributions are taken into account. We found numerically that: (a) the NLO contributions can provide $\sim 40\%$ enhancement to the LO PQCD predictions for ${\cal B}(\bar{B}_s^0 \to K^0 \bar{K}^{*0})$ and ${\cal B}(\bar{B}_s^0 \to K^{\pm}K^{*\mp})$, or a $\sim 37\%$ reduction to \calb(\bar{B}_s^0 \to \pi^{-} K^{*+}), and we confirmed that the inclusion of the known NLO contributions can improve significantly the agreement between the theory and those currently available experimental measurements, (b) the total effects on the PQCD predictions for the relevant $B\to P$ transition form factors after the inclusion of the NLO twist-2 and twist-3 contributions is generally small in magnitude: less than $10\%$ enhancement respect to the leading order result, (c) for the "tree" dominated decay $\bar B_s^0\to K^+ \rho^-$ and the "color-suppressed-tree" decay $\bar B_s^0\to \pi^0 K^{*0}$, the big difference between the PQCD predictions for their branching ratios are induced by different topological structure and by interference effects among the decay amplitude ${\cal A}_{T,C}$ and ${\cal A}_P$: constructive for the first decay but destructive for the second one, and (d) for \bar{B}_s^0 \to V(\eta, \etar) decays, the complex pattern of the PQCD predictions for their branching ratios can be understood by rather different topological structures and the interference effects between the decay amplitude \cala(V\eta_q) and \cala(V\eta_s) due to the \eta-\etar mixing.Comment: 18 pages, 2 figures, 3 tables. Some modifications of the text. Several new references are adde

Full counting statistics of renormalized dynamics in open quantum transport system

The internal dynamics of a double quantum dot system is renormalized due to coupling respectively with transport electrodes and a dissipative heat bath. Their essential differences are identified unambiguously in the context of full counting statistics. The electrode coupling caused level detuning renormalization gives rise to a fast-to-slow transport mechanism, which is not resolved at all in the average current, but revealed uniquely by pronounced super-Poissonian shot noise and skewness. The heat bath coupling introduces an interdot coupling renormalization, which results in asymmetric Fano factor and an intriguing change of line shape in the skewness.Comment: 9 pages, 5 figure

Propagation Characteristics Of Density Currents And Implications To Pollutant Transport In A Stratified Reservoir

With global warming, the frequency and intensity of extreme rainfall events were predicted to change more dramatically in the near future while the amount of total precipitation will change slightly. Large volume of turbid inflow will enter the source water reservoir after a heavy rainfall, and evolve in various types of density currents depending on the density difference between the inflow and background water. Density currents play an important role in the thermal structure and pollutant transport in the reservoir. Understanding the behaviors of density current is fundamental to study the changes of source water quality during the flooding season. Characteristics of density currents were first experimentally investigated in a pilot stratified reservoir with a length of 2.0m and a depth of 0.54m, in which the thermal stratification was achieved with a heating method. When the stratification stability indexes were of 0.0112～0.0197 m-1 and the buoyancy frequencies were of 0.3314～0.4393 s-1, the turbid inflow was observed to separate from the bed slope and to propagate horizontally into its equilibrium layer, namely interflow. The separation depth of density currents and the thickness of the interflow were both smaller in the strong stratification cases than those in the weak cases, which had an important impact on the pollutant transport in the reservoir. Propagation characteristics of density currents and its implications to pollutant transport were systemically explored by numerically simulating behaviors of density currents under different conditions of stratification stability index, inflow velocity and sediment content of inflow. After careful calibration of Euler-Euler model, the simulated separation depth of density currents and the thickness of the interflow agreed well with the experimental ones, which showed the propagation of inflow was closely related to the stratification level. Impacts of inflow velocity and sediment content of inflow on the propagation of density currents were different under the simulated conditions. When the volume fraction of sediment in the inflow was increased from 0.025% to 0.20%, the separation depth of density currents was decreased from 21.0cm to 18.5cm, the thickness of the interflow was slightly increased from 6.2cm to 7.8cm, but the heights of the internal hydraulic jump were almost the same. The inflow velocity mainly influenced the time of developing the interflow, the developing time decreased as the inflow velocity increased, which implied the water quality would deteriorate quickly after a heavy rainfall. Under larger inflow velocity conditions, mixing between the inflow and background water was stronger due to the higher energy carried by the inflow, and this caused the larger depth of interflow and the bigger height of internal hydraulic jump, which indicated the pollutants carried by turbid inflow would be transported more widely

Single-photon transport and mechanical NOON state generation in microcavity optomechanics

We investigate the single-photon transport in a single-mode optical fiber coupled to an optomechanical system in the single-photon strong-coupling regime. The single-photon transmission amplitude is analytically obtained with a real-space approach and the effects of thermal noises are studied via master-equation simulations. The results provide an explicit understanding of optomechanical interaction and offer a useful guide for manipulating single photons in optomechanical systems. Based on the theoretical framework, we further propose a scheme to generate the mechanical NOON states with arbitrary phonon numbers by measuring the sideband photons. The probability for generating the NOON state with five phonons is over 0.15.Comment: 13 pages, 6 figure