58,775 research outputs found

    Recent progress in random metric theory and its applications to conditional risk measures

    Full text link
    The purpose of this paper is to give a selective survey on recent progress in random metric theory and its applications to conditional risk measures. This paper includes eight sections. Section 1 is a longer introduction, which gives a brief introduction to random metric theory, risk measures and conditional risk measures. Section 2 gives the central framework in random metric theory, topological structures, important examples, the notions of a random conjugate space and the Hahn-Banach theorems for random linear functionals. Section 3 gives several important representation theorems for random conjugate spaces. Section 4 gives characterizations for a complete random normed module to be random reflexive. Section 5 gives hyperplane separation theorems currently available in random locally convex modules. Section 6 gives the theory of random duality with respect to the locally L0L^{0}-convex topology and in particular a characterization for a locally L0L^{0}-convex module to be L0L^{0}-pre-barreled. Section 7 gives some basic results on L0L^{0}-convex analysis together with some applications to conditional risk measures. Finally, Section 8 is devoted to extensions of conditional convex risk measures, which shows that every representable LL^{\infty}-type of conditional convex risk measure and every continuous LpL^{p}-type of convex conditional risk measure (1p<+1\leq p<+\infty) can be extended to an LF(E)L^{\infty}_{\cal F}({\cal E})-type of σϵ,λ(LF(E),LF1(E))\sigma_{\epsilon,\lambda}(L^{\infty}_{\cal F}({\cal E}), L^{1}_{\cal F}({\cal E}))-lower semicontinuous conditional convex risk measure and an LFp(E)L^{p}_{\cal F}({\cal E})-type of Tϵ,λ{\cal T}_{\epsilon,\lambda}-continuous conditional convex risk measure (1p<+1\leq p<+\infty), respectively.Comment: 37 page

    \Lambda_b \to \Lambda_c P(V) Nonleptonic Weak Decays

    Full text link
    The two-body nonleptonic weak decays of \Lambda_b \to \Lambda_c P(V) (P and V represent pseudoscalar and vector mesons respectively) are analyzed in two models, one is the Bethe-Salpeter (B-S) model and the other is the hadronic wave function model. The calculations are carried out in the factorization approach. The obtained results are compared with other model calculations.Comment: 18 pages, Late

    Spectra of Baryons Containing Two Heavy Quarks in Potential Model

    Get PDF
    In this work, we employ the effective vertices for interaction between diquarks (scalar or axial-vector) and gluon where the form factors are derived in terms of the B-S equation, to obtain the potential for baryons including a light quark and a heavy diquark. The concerned phenomenological parameters are obtained by fitting data of B()B^{(*)}-mesons instead of the heavy quarkonia. The operator ordering problem in quantum mechanics is discussed. Our numerical results indicate that the mass splitting between B3/2(V),B1/2(V)B_{3/2}(V), B_{1/2}(V) and B1/2(S)B_{1/2}(S) is very small and it is consistent with the heavy quark effective theory (HQET).Comment: 16 page

    Quantitative test of a quantum theory for the resistive transition in a superconducting single-walled carbon nanotube bundle

    Full text link
    The phenomenon of superconductivity depends on the coherence of the phase of the superconducting order parameter. The resistive transition in quasi-one-dimensional (quasi-1D) superconductors is broad because of a large phase fluctuation. We show that the resistive transition of a superconducting single-walled carbon nanotube bundle is in quantitative agreement with the Langer-Ambegaokar-McCumber-Halperin (LAMH) theory. We also demonstrate that the resistive transition below T^*_c = 0.89T_c0 is simply proportional to exp [-(3\beta T^*_c/T)(1-T/T^*_c)^3/2], where the barrier height has the same form as that predicted by the LAMH theory and T_c0 is the mean field superconducting transition temperature.Comment: 4 pages, 3 figure

    Why not Merge the International Monetary Fund (IMF) with the International Bank for Reconstruction and Development (World Bank)

    Get PDF
    Motivation: Cellular Electron CryoTomography (CECT) is an emerging 3D imaging technique that visualizes subcellular organization of single cells at sub-molecular resolution and in near-native state. CECT captures large numbers of macromolecular complexes of highly diverse structures and abundances. However, the structural complexity and imaging limits complicate the systematic de novo structural recovery and recognition of these macromolecular complexes. Efficient and accurate reference-free subtomogram averaging and classification represent the most critical tasks for such analysis. Existing subtomogram alignment based methods are prone to the missing wedge effects and low signal-to-noise ratio (SNR). Moreover, existing maximum-likelihood based methods rely on integration operations, which are in principle computationally infeasible for accurate calculation. Results: Built on existing works, we propose an integrated method, Fast Alignment Maximum Likelihood method (FAML), which uses fast subtomogram alignment to sample sub-optimal rigid transformations. The transformations are then used to approximate integrals for maximum-likelihood update of subtomogram averages through expectation-maximization algorithm. Our tests on simulated and experimental subtomograms showed that, compared to our previously developed fast alignment method (FA), FAML is significantly more robust to noise and missing wedge effects with moderate increases of computation cost. Besides, FAML performs well with significantly fewer input subtomograms when the FA method fails. Therefore, FAML can serve as a key component for improved construction of initial structuralmodels frommacromolecules captured by CECT

    A large-scale one-way quantum computer in an array of coupled cavities

    Full text link
    We propose an efficient method to realize a large-scale one-way quantum computer in a two-dimensional (2D) array of coupled cavities, based on coherent displacements of an arbitrary state of cavity fields in a closed phase space. Due to the nontrivial geometric phase shifts accumulating only between the qubits in nearest-neighbor cavities, a large-scale 2D cluster state can be created within a short time. We discuss the feasibility of our method for scale solid-state quantum computationComment: 5 pages, 3 figure
    corecore