7,957 research outputs found

    Generalized Gaussian Process Regression Model for Non-Gaussian Functional Data

    Full text link
    In this paper we propose a generalized Gaussian process concurrent regression model for functional data where the functional response variable has a binomial, Poisson or other non-Gaussian distribution from an exponential family while the covariates are mixed functional and scalar variables. The proposed model offers a nonparametric generalized concurrent regression method for functional data with multi-dimensional covariates, and provides a natural framework on modeling common mean structure and covariance structure simultaneously for repeatedly observed functional data. The mean structure provides an overall information about the observations, while the covariance structure can be used to catch up the characteristic of each individual batch. The prior specification of covariance kernel enables us to accommodate a wide class of nonlinear models. The definition of the model, the inference and the implementation as well as its asymptotic properties are discussed. Several numerical examples with different non-Gaussian response variables are presented. Some technical details and more numerical examples as well as an extension of the model are provided as supplementary materials

    Limits on the Dark Matter from AMS-02 antiproton and positron fraction data

    Full text link
    We derive limits on the dark matter annihilation cross section and lifetime using measurements of the AMS-02 antiproton ratio and positron fraction data. In deriving the limits, we consider the scenario of secondary particles accelerated in supernova remnants (SNRs) which has been argued to be able to reasonably account for the AMS-02 high energy positron/antiproton fraction data. We parameterize the contribution of secondary particles accelerated in SNRs and then fit the observational data within the conventional cosmic ray propagation model by adopting the GALPROP code. We use the likelihood ratio test to determine the 95%\% confidence level upper limits of the possible dark matter (DM) contribution to the antiproton/positron fractions measured by AMS-02. Our limits are stronger than that set by the Fermi-LAT gamma-ray Pass 8 data of the dwarf spheroidal satellite galaxies. We also show that the solar modulation (cosmic ray propagation) parameters can play a non-negligible role in modifying the constraints on the dark matter annihilation cross section and lifetime for mχ100m_\chi100 GeV), where mχm_\chi is the rest mass of the dark matter particles. Using this results, we also put limits on the effective field theory of dark matter

    Exhaustion of isoperimetric regions in asymptotically hyperbolic manifolds with scalar curvature Rβ‰₯βˆ’6R\geq -6

    Full text link
    In this paper, aimed at exploring the fundamental properties of isoperimetric region in 33-manifold (M3,g)(M^3,g) which is asymptotic to Anti-de Sitter-Schwarzschild manifold with scalar curvature Rβ‰₯βˆ’6R\geq -6, we prove that connected isoperimetric region {Di}\{D_i\} with Hg3(Di)β‰₯Ξ΄0>0\mathcal{H}_g ^3(D_i)\geq \delta_0>0 cannot slide off to the infinity of (M3,g)(M^3,g) provided that (M3,g)(M^3,g) is not isometric to the hyperbolic space. Furthermore, we prove that isoperimetric region {Di}\{D_i\} with topological sphere {βˆ‚Di}\{\partial D_i\} as boundary is exhausting regions of MM if Hawking mass mH(βˆ‚Di)m_H(\partial D_i) has uniform bound. In the case of exhausting isoperimetric region, we obtain a formula on expansion of isoperimetric profile in terms of renormalized volume.Comment: To appear in CA

    A Pyramid Scheme Model Based on "Consumption Rebate" Frauds

    Full text link
    There are various types of pyramid schemes which have inflicted or are inflicting losses on many people in the world. We propose a pyramid scheme model which has the principal characters of many pyramid schemes appeared in recent years: promising high returns, rewarding the participants recruiting the next generation of participants, and the organizer will take all the money away when he finds the money from the new participants is not enough to pay the previous participants interest and rewards. We assume the pyramid scheme carries on in the tree network, ER random network, SW small-world network or BA scale-free network respectively, then give the analytical results of how many generations the pyramid scheme can last in these cases. We also use our model to analyse a pyramid scheme in the real world and we find the connections between participants in the pyramid scheme may constitute a SW small-world network.Comment: 17 pages, 10 figure

    Exact results of two-component Fermi gas in a hard wall trap

    Full text link
    We investigate the ground state properties of a one-dimensional two-component ultra-cold Fermi gas in an infinite potential well. Exact Bethe ansatz solution is used to calculate the many-body wave function of the system. Then we evaluate the single-particle reduced density matrix and two-particle density density correlations of the system for different interaction strengths. We find that the momentum density distributions of the strongly interacting two-component Fermi gas is distinct from that of free spinless Fermi gas although their position density distributions are similar. This interacting system may be experimentally accessible using ultra-cold atoms.Comment: 6 pages, 6 page

    D(βˆ—)ND^{(\ast)}N interaction and the structure of Ξ£c(2800)\Sigma_c(2800) and Ξ›c(2940)\Lambda_c(2940) in chiral effective field theory

    Full text link
    We study the DNDN and Dβˆ—ND^\ast N interactions to probe the inner structure of Ξ£c(2800)\Sigma_c(2800) and Ξ›c(2940)\Lambda_c(2940) with the chiral effective field theory to the next-to-leading order. We consider the contact term, one-pion-exchange and two-pion-exchange contributions to characterize the short-, long- and mid-range interactions of the D(βˆ—)ND^{(\ast)}N systems. The low energy constants of the D(βˆ—)ND^{(\ast)}N systems are related to those of the NNΛ‰N\bar{N} interaction with quark level Lagrangian that inspired by the resonance saturation model. The Ξ”(1232)\Delta(1232) degree of freedom is also included in the loop diagrams. The attractive potential in the [DN]J=1/2I=1[DN]_{J=1/2}^{I=1} channel is too weak to form bound state, which indicates the explanation of Ξ£c(2800)\Sigma_c(2800) as the compact charmed baryon is more reasonable. Meanwhile, the potentials of the isoscalar channels are deep enough to yield the molecular states. We obtain the masses of the [DN]J=1/2I=0[DN]_{J=1/2}^{I=0}, [Dβˆ—N]J=1/2I=0[D^\ast N]_{J=1/2}^{I=0} and [Dβˆ—N]J=3/2I=0[D^\ast N]_{J=3/2}^{I=0} systems to be 2792.02792.0 MeV, 2943.62943.6 MeV and 2938.42938.4 MeV, respectively. The Ξ›c(2940)\Lambda_c(2940) is probably the isoscalar Dβˆ—ND^\ast N molecule considering its low mass puzzle. Besides, the Ξ›c(2940)\Lambda_c(2940) signal might contain the spin-12\frac{1}{2} and spin-32\frac{3}{2} two structures, which can qualitatively explain the significant decay ratio to D0pD^0p and Ξ£cΟ€\Sigma_c\pi. We also study the BΛ‰(βˆ—)N\bar{B}^{(\ast)}N systems and predict the possible molecular states in the isoscalar channels. We hope experimentalists could hunt for the open charmed molecular pentaquarks in the Ξ›c+Ο€+Ο€βˆ’\Lambda_c^+\pi^+\pi^- final state.Comment: 11 pages, 4 figures and 4 table

    Clique Gossiping

    Full text link
    This paper proposes and investigates a framework for clique gossip protocols. As complete subnetworks, the existence of cliques is ubiquitous in various social, computer, and engineering networks. By clique gossiping, nodes interact with each other along a sequence of cliques. Clique-gossip protocols are defined as arbitrary linear node interactions where node states are vectors evolving as linear dynamical systems. Such protocols become clique-gossip averaging algorithms when node states are scalars under averaging rules. We generalize the classical notion of line graph to capture the essential node interaction structure induced by both the underlying network and the specific clique sequence. We prove a fundamental eigenvalue invariance principle for periodic clique-gossip protocols, which implies that any permutation of the clique sequence leads to the same spectrum for the overall state transition when the generalized line graph contains no cycle. We also prove that for a network with nn nodes, cliques with smaller sizes determined by factors of nn can always be constructed leading to finite-time convergent clique-gossip averaging algorithms, provided nn is not a prime number. Particularly, such finite-time convergence can be achieved with cliques of equal size mm if and only if nn is divisible by mm and they have exactly the same prime factors. A proven fastest finite-time convergent clique-gossip algorithm is constructed for clique-gossiping using size-mm cliques. Additionally, the acceleration effects of clique-gossiping are illustrated via numerical examples

    Constraining the anomalous Higgs boson coupling in HH+Ξ³\gamma production

    Full text link
    Higgs boson production in association with a photon (HH+Ξ³\gamma) offers a promising channel to test the Higgs boson to photon coupling at various energy scales. Its potential sensitivity to anomalous couplings of the Higgs boson has not been explored with the proton-proton collision data. In this paper, we reinterpret the latest ATLAS HH+Ξ³\gamma resonance search results within the Standard Model effective field theory (EFT) framework, using 36.1 fbβˆ’1^{-1} of proton-proton collision data recorded with the ATLAS detector at s=13\sqrt{s}=13 TeV. Constraints on the Wilson coefficients of dimension-six EFT operators related to the Higgs boson to photon coupling are provided for the first time in the HH+Ξ³\gamma final state at the LHC.Comment: 10 pages, 3 figure

    Hierarchicality of Trade Flow Networks Reveals Complexity of Products

    Full text link
    With globalization, countries are more connected than before by trading flows, which currently amount to at least 36 trillion dollars. Interestingly, approximately 30-60 percent of global exports consist of intermediate products. Therefore, the trade flow network of a particular product with high added values can be regarded as a value chain. The problem is weather we can discriminate between these products based on their unique flow network structure. This paper applies the flow analysis method developed in ecology to 638 trading flow networks of different products. We claim that the allometric scaling exponent Ξ·\eta can be used to characterize the degree of hierarchicality of a flow network, i.e., whether the trading products flow on long hierarchical chains. Then, the flow networks of products with higher added values and complexity, such as machinery&transport equipment with larger exponents, are highlighted. These higher values indicate that their trade flow networks are more hierarchical. As a result, without extra data such as global input-output table, we can identify the product categories with higher complexity and the relative importance of a country in the global value chain solely by the trading network.Comment: 14 pages,7 figure

    Flow Decomposition Reveals Dynamical Structure of Markov Process

    Full text link
    Markov process is widely applied in almost all aspects of literature, especially important for understanding non-equilibrium processes. We introduce a decomposition to general Markov process in this paper. This decomposition decomposes the process into 3 independent parts: stationary distribution, symmetric detailed-balance part and anti-symmetric breaking detailed-balance part. This complete decomposition captures the steady state as well as the dynamics of the process, providing an elegant perspective for construction or analyzing problems. In light of the decomposition, a unique definition of relative entropy is found to formally separate the effect of detailed-balance part and breaking detailed-balance part. We find that the relative Gini entropy production introduced in the paper is not affected by the non-detailed balance part of the process. This property do not holds for other entropy definition in general discrete case
    • …
    corecore