Studying Double Charm Decays of B_{u,d} and B_{s} Mesons in the MSSM with R-parity Violation

Motivated by the possible large direct CP asymmetry of \bar{B}^0_d \to D^+ D^- decay measured by Belle collaboration, we investigate double charm B_{u,d} and B_s decays in the minimal supersymmetric standard model with R-parity violation. We derive the bounds on relevant R-parity violating couplings from the current experimental data, which show quite consistent measurements among relative collaborations. Using the constrained parameter spaces, we explore R-parity violating effects on other observables in these decays, which have not been measured or have not been well measured yet. We find that the R-parity violating effects on the mixing-induced CP asymmetries of \bar{B}^0_d \to D^{(*)+} D^{(*)-} and \bar{B}^0_s \to D^{(*)+}_s D^{(*)-}_s decays could be very large, nevertheless the R-parity violating effects on the direct CP asymmetries could not be large enough to explain the large direct CP violation of \bar{B}^0_d \to D^{+} D^{-} from Belle. Our results could be used to probe R-parity violating effects and will correlate with searches for direct R-parity violating signals in future experiments.Comment: 28 pages and 6 figures, matches published versio

Controlled and combined remote implementations of partially unknown quantum operations of multiqubits using GHZ states

We propose and prove protocols of controlled and combined remote implementations of partially unknown quantum operations belonging to the restricted sets [An Min Wang: PRA, \textbf{74}, 032317(2006)] using GHZ states. We detailedly describe the protocols in the cases of one qubit, respectively, with one controller and with two senders. Then we extend the protocols to the cases of multiqubits with many controllers and two senders. Because our protocols have to demand the controller(s)'s startup and authorization or two senders together working and cooperations, the controlled and combined remote implementations of quantum operations definitely can enhance the security of remote quantum information processing and potentially have more applications. Moreover, our protocol with two senders is helpful to farthest arrive at the power of remote implementations of quantum operations in theory since the different senders perhaps have different operational resources and different operational rights in practice.Comment: 26 pages, the submitted versio

Scheme for remote implementation of partially unknown quantum operation of two qubits in cavity QED

By constructing the recovery operations of the protocol of remote implementation of partially unknown quantum operation of two qubits [An Min Wang: PRA, \textbf{74}, 032317(2006)], we present a scheme to implement it in cavity QED. Long-lived Rydberg atoms are used as qubits, and the interaction between the atoms and the field of cavity is a nonresonant one. Finally, we analyze the experimental feasibility of this scheme.Comment: 7 pages, 2 figure

Quantum Criticality from in-situ Density Imaging

We perform large-scale Quantum Monte Carlo (QMC) simulations for strongly interacting bosons in a 2D optical lattice trap, and confirm an excellent agreement with the benchmarking in-situ density measurements by the Chicago group [1]. We further present a general finite temperature phase diagram both for the uniform and the trapped systems, and demonstrate how the universal scaling properties near the superfluid(SF)-to-Mott insulator(MI) transition can be observed by analysing the in-situ density profile. The characteristic temperature to find such quantum criticality is estimated to be of the order of the single-particle bandwidth, which should be achievable in the present or near future experiments. Finally, we examine the validity regime of the local fluctuation-dissipation theorem (FDT), which can be a used as a thermometry in the strongly interacting regime.Comment: 4 page

Spins of the supermassive black hole in M87: new constraints from TeV observations

The rapid TeV $\gamma-$ray variability detected in the well-known nearby radio galaxy M87 implies an extremely compact emission region (5-10 Schwarzschild radii) near the horizon of the supermassive black hole in the galactic center. TeV photons are affected by dilution due to interaction with the radiation field of the advection-dominated accretion flow (ADAF) around the black hole, and can thus be used to probe the innermost regions around the black hole. We calculate the optical depth of the ADAF radiation field to the TeV photons and find it strongly depends on the spin of the black hole. We find that transparent radii of 10 TeV photons are of $5R_{\rm S}$ and $13R_{\rm S}$ for the maximally rotating and non-rotating black holes, respectively. With the observations, the calculated transparent radii strongly suggest the black hole is spinning fast in the galaxy. TeV photons could be used as a powerful diagnostic for estimating black hole spins in galaxies in the future.Comment: 4 pages, 4 figures. to appear in ApJ

Modeling relation paths for knowledge base completion via joint adversarial training

Knowledge Base Completion (KBC), which aims at determining the missing relations between entity pairs, has received increasing attention in recent years. Most existing KBC methods focus on either embedding the Knowledge Base (KB) into a specific semantic space or leveraging the joint probability of Random Walks (RWs) on multi-hop paths. Only a few unified models take both semantic and path-related features into consideration with adequacy. In this paper, we propose a novel method to explore the intrinsic relationship between the single relation (i.e. 1-hop path) and multi-hop paths between paired entities. We use Hierarchical Attention Networks (HANs) to select important relations in multi-hop paths and encode them into low-dimensional vectors. By treating relations and multi-hop paths as two different input sources, we use a feature extractor, which is shared by two downstream components (i.e. relation classifier and source discriminator), to capture shared/similar information between them. By joint adversarial training, we encourage our model to extract features from the multi-hop paths which are representative for relation completion. We apply the trained model (except for the source discriminator) to several large-scale KBs for relation completion. Experimental results show that our method outperforms existing path information-based approaches. Since each sub-module of our model can be well interpreted, our model can be applied to a large number of relation learning tasks.Comment: Accepted by Knowledge-Based System

Magnetic field dependence of antiferromagnetic resonance in NiO

We report on measurements of magnetic field and temperature dependence of antiferromagnetic resonances in the prototypical antiferromagnet NiO. The frequencies of the magnetic resonances in the vicinity of 1 THz have been determined in the time-domain via time-resolved Faraday measurements after selective excitation by narrow-band superradiant terahertz (THz) pulses at temperatures down to 3 K and in magnetic fields up to 10 T. The measurements reveal two antiferromagnetic resonance modes, which can be distinguished by their characteristic magnetic field dependencies. The nature of the two modes is discussed by comparison to an eight-sublattice antiferromagnetic model, which includes superexchange between the next-nearest-neighbor Ni spins, magnetic dipolar interactions, cubic magneto-crystalline anisotropy, and Zeeman interaction with the external magnetic field. Our study indicates that a two-sublattice model is insufficient for the description of spin dynamics in NiO, while the magnetic-dipolar interactions and magneto-crystalline anisotropy play important roles

A Limit Relation between Black Hole Mass and Hβ\beta Width: Testing Super-Eddington Accretion in Active Galactic Nuclei

(abbreviated) We show that there is a limit relation between the black hole mass and the width at the half maximum of H$\beta$ for active galactic nuclei (AGNs) with super-Eddington accretion rates. When a black hole has a super-Eddington accretion rate, the empirical relation of reverberation mapping has two possible ways. First, it reduces to a relation between the black hole mass and the size of the broad line region due to the photon trapping effects inside the accretion disk. For the Kaspi et al.'s empirical reverberation relation, we get the limit relation as $M_{\rm BH}=(2.9 - 12.6)\times 10^6M_{\odot} (\upsilon_{\rm FWHM}/10^3{\rm km s^{-1}})^{6.67}$, called as the Eddington limit. Second, the Eddington limit luminosity will be relaxed if the trapped photons can escape from the magnetized super-Eddington accretion disk via the photon bubble instability, and the size of the broad line region will be enlarged according to the empirical reverberation relation, leading to a relatively narrow width of H$\beta$. We call this the Begelman limit. Super-Eddington accretions in a sample composed of 164 AGNs have been searched by this limit relation. We find there are a handful of objects locate between the Eddington and Begelman limit lines, they may be candidates of super-Eddington accretors in a hybrid structure of photon trapping and photon bubble instability. The maximum width of H$\beta$ is in the reange of $(3.0 - 3.8)\times 10^3$ km s$^{-1}$ for the maximum mass black holes with super-Eddington accretion rates among AGNs. We suggest that this limit relation is more reliable and convenient to test whether a source is super-Eddington and useful to probe the structure of the super-Eddington accretion process.Comment: 5 pages (emulateapj5.sty), 1 figure. Astronomical Journal, 125 (June Issue 2003) in pres