Charmless Two-body B(Bs)→VPB(B_s)\to VP decays In Soft-Collinear-Effective-Theory

We provide the analysis of charmless two-body $B\to VP$ decays under the framework of the soft-collinear-effective-theory (SCET), where $V(P)$ denotes a light vector (pseudoscalar) meson. Besides the leading power contributions, some power corrections (chiraly enhanced penguins) are also taken into account. Using the current available $B\to PP$ and $B\to VP$ experimental data on branching fractions and CP asymmetry variables, we find two kinds of solutions in $\chi^2$ fit for the 16 non-perturbative inputs which are essential in the 87 $B\to PP$ and $B\to VP$ decay channels. Chiraly enhanced penguins can change several charming penguins sizably, since they share the same topology. However, most of the other non-perturbative inputs and predictions on branching ratios and CP asymmetries are not changed too much. With the two sets of inputs, we predict the branching fractions and CP asymmetries of other modes especially $B_s\to VP$ decays. The agreements and differences with results in QCD factorization and perturbative QCD approach are analyzed. We also study the time-dependent CP asymmetries in channels with CP eigenstates in the final states and some other channels such as $\bar B^0/B^0\to\pi^\pm\rho^\mp$ and $\bar B_s^0/B_s^0\to K^\pm K^{*\mp}$. In the perturbative QCD approach, the $(S-P)(S+P)$ penguins in annihilation diagrams play an important role. Although they have the same topology with charming penguins in SCET, there are many differences between the two objects in weak phases, magnitudes, strong phases and factorization properties.Comment: 34 pages, revtex, 2 figures, published at PR

Modeling Fault Propagation Paths in Power Systems: A New Framework Based on Event SNP Systems With Neurotransmitter Concentration

To reveal fault propagation paths is one of the most critical studies for the analysis of power system security; however, it is rather dif cult. This paper proposes a new framework for the fault propagation path modeling method of power systems based on membrane computing.We rst model the fault propagation paths by proposing the event spiking neural P systems (Ev-SNP systems) with neurotransmitter concentration, which can intuitively reveal the fault propagation path due to the ability of its graphics models and parallel knowledge reasoning. The neurotransmitter concentration is used to represent the probability and gravity degree of fault propagation among synapses. Then, to reduce the dimension of the Ev-SNP system and make them suitable for large-scale power systems, we propose a model reduction method for the Ev-SNP system and devise its simpli ed model by constructing single-input and single-output neurons, called reduction-SNP system (RSNP system). Moreover, we apply the RSNP system to the IEEE 14- and 118-bus systems to study their fault propagation paths. The proposed approach rst extends the SNP systems to a large-scaled application in critical infrastructures from a single element to a system-wise investigation as well as from the post-ante fault diagnosis to a new ex-ante fault propagation path prediction, and the simulation results show a new success and promising approach to the engineering domain

Fractional Quantum Hall Effect in Topological Flat Bands with Chern Number Two

Recent theoretical works have demonstrated various robust Abelian and non-Abelian fractional topological phases in lattice models with topological flat bands carrying Chern number C=1. Here we study hard-core bosons and interacting fermions in a three-band triangular-lattice model with the lowest topological flat band of Chern number C=2. We find convincing numerical evidence of bosonic fractional quantum Hall effect at the $\nu=1/3$ filling characterized by three-fold quasi-degeneracy of ground states on a torus, a fractional Chern number for each ground state, a robust spectrum gap, and a gap in quasihole excitation spectrum. We also observe numerical evidence of a robust fermionic fractional quantum Hall effect for spinless fermions at the $\nu=1/5$ filling with short-range interactions.Comment: 5 pages, 7 figures, with Supplementary Materia

Non-Abelian Quantum Hall Effect in Topological Flat Bands

Inspired by recent theoretical discovery of robust fractional topological phases without a magnetic field, we search for the non-Abelian quantum Hall effect (NA-QHE) in lattice models with topological flat bands (TFBs). Through extensive numerical studies on the Haldane model with three-body hard-core bosons loaded into a TFB, we find convincing numerical evidence of a stable $\nu=1$ bosonic NA-QHE, with the characteristic three-fold quasi-degeneracy of ground states on a torus, a quantized Chern number, and a robust spectrum gap. Moreover, the spectrum for two-quasihole states also shows a finite energy gap, with the number of states in the lower energy sector satisfying the same counting rule as the Moore-Read Pfaffian state.Comment: 5 pages, 7 figure

9,9-Dimethyl-12-(4-nitro­phen­yl)-9,10-dihydro-12H-benzo[a]xanthen-11(8H)-one

In the mol­ecular structure of the title compound, C25H21NO4, the pyran ring adopts a flattened boat conformation, while the cyclo­hexenone ring is in an envelope conformation. The 4-nitro­phenyl ring is almost perpendicular to the pyran ring [dihedral angle = 89.39 (1)°]. In the crystal, mol­ecules are connected by inter­molecular C—H⋯O hydrogen bonds

Entanglement production and decoherence-free subspace of two single-mode cavities embedded in a common environment

A system consisting of two identical single-mode cavities coupled to a common environment is investigated within the framework of algebraic dynamics. Based on the left and right representations of the Heisenberg-Weyl algebra, the algebraic structure of the master equation is explored and exact analytical solutions of this system are obtained. It is shown that for such a system, the environment can produce entanglement in contrast to its commonly believed role of destroying entanglement. In addition, the collective zero-mode eigen solutions of the system are found to be free of decoherence against the dissipation of the environment. These decoherence-free states may be useful in quantum information and quantum computation.Comment: 10 pages, 7 figures, Revtex

Reconsideration of Second Harmonic Generation from neat Air/Water Interface: Broken of Kleinman Symmetry from Dipolar Contribution

It has been generally accepted that there are significant quadrupolar and bulk contributions to the second harmonic generation (SHG) reflected from the neat air/water interface, as well as common liquid interfaces. Because there has been no general methodology to determine the quadrupolar and bulk contributions to the SHG signal from a liquid interface, this conclusion was reached based on the following two experimental phenomena. Namely, the broken of the macroscopic Kleinman symmetry, and the significant temperature dependence of the SHG signal from the neat air/water interface. However, because sum frequency generation vibrational spectroscopy (SFG-VS) measurement of the neat air/water interface observed no apparent temperature dependence, the temperature dependence in the SHG measurement has been reexamined and proven to be an experimental artifact. Here we present a complete microscopic analysis of the susceptibility tensors of the air/water interface, and show that dipolar contribution alone can be used to address the issue of broken of the macroscopic Kleinman symmetry at the neat air/water interface. Using this analysis, the orientation of the water molecules at the interface can be obtained, and it is consistent with the measurement from SFG-VS. Therefore, the key rationales to conclude significantly quadrupolar and bulk contributions to the SHG signal of the neat air/water interface can no longer be considered as valid as before. This new understanding of the air/water interface can shed light on our understanding of the nonlinear optical responses from other molecular interfaces as well