19,800 research outputs found

    Eguchi-Kawai model with dynamical adjoint fermions

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    It is believed that fermions in adjoint representation on single site lattice will restore the center symmetry, which is a crucial requirement for the volume independence of large-N lattice gauge theories. We present a perturbative analysis which supports the assumption for overlap fermions, but shows that center symmetry is broken for naive fermions.Comment: 7 pages, 4 figures, Contribution to The XXVII International Symposium on Lattice Field Theor

    Lacunary Fourier series and a qualitative uncertainty principle for compact Lie groups

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    We define lacunary Fourier series on a compact connected semisimple Lie group GG. If fL1(G)f \in L^1(G) has lacunary Fourier series, and vanishes on a non empty open set, then we prove that ff vanishes identically. This may be viewed as a qualitative uncertainty principle

    Truncated Overlap Fermions

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    In this talk I propose a new computational scheme with overlap fermions and a fast algorithm to invert the corresponding Dirac operator.Comment: LATTICE99(algorithms

    Asymptotics of Harish-Chandra expansions, bounded hypergeometric functions associated with root systems, and applications

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    A series expansion for Heckman-Opdam hypergeometric functions φλ\varphi_\lambda is obtained for all λaC.\lambda \in \mathfrak a^*_{\mathbb C}. As a consequence, estimates for φλ\varphi_\lambda away from the walls of a Weyl chamber are established. We also characterize the bounded hypergeometric functions and thus prove an analogue of the celebrated theorem of Helgason and Johnson on the bounded spherical functions on a Riemannian symmetric space of the noncompact type. The LpL^p-theory for the hypergeometric Fourier transform is developed for 0<p<20<p<2. In particular, an inversion formula is proved when 1p<21\leq p <2

    struc2vec: Learning Node Representations from Structural Identity

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    Structural identity is a concept of symmetry in which network nodes are identified according to the network structure and their relationship to other nodes. Structural identity has been studied in theory and practice over the past decades, but only recently has it been addressed with representational learning techniques. This work presents struc2vec, a novel and flexible framework for learning latent representations for the structural identity of nodes. struc2vec uses a hierarchy to measure node similarity at different scales, and constructs a multilayer graph to encode structural similarities and generate structural context for nodes. Numerical experiments indicate that state-of-the-art techniques for learning node representations fail in capturing stronger notions of structural identity, while struc2vec exhibits much superior performance in this task, as it overcomes limitations of prior approaches. As a consequence, numerical experiments indicate that struc2vec improves performance on classification tasks that depend more on structural identity.Comment: 10 pages, KDD2017, Research Trac

    Implementation and validation of a wake model for vortex-surface interactions in low speed forward flight

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    The wake model was implemented using a VAX 750 and a Microvax II workstation. Online graphics capability using a DISSPLA graphics package. The rotor model used by Beddoes was significantly extended to include azimuthal variations due to forward flight and a simplified scheme for locating critical points where vortex elements are placed. A test case was obtained for validation of the predictions of induced velocity. Comparison of the results indicates that the code requires some more features before satisfactory predictions can be made over the whole rotor disk. Specifically, shed vorticity due to the azimuthal variation of blade loading must be incorporated into the model. Interactions between vortices shed from the four blades of the model rotor must be included. The Scully code for calculating the velocity field is being modified in parallel with these efforts to enable comparison with experimental data. To date, some comparisons with flow visualization data obtained at Georgia Tech were performed and show good agreement for the isolated rotor case. Comparison of time-resolved velocity data obtained at Georgia Tech also shows good agreement. Modifications are being implemented to enable generation of time-averaged results for comparison with NASA data

    Disordered social media use and risky drinking in young adults:Differential associations with addiction-linked traits

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    Background Excessive or compulsive use of social media has been likened to an addiction, similar to other behavioural addictions such as pathological gambling or Internet addiction. This investigation sought to determine the degree to which personality traits associated with such disordered social media use overlap with those known to predict problematic substance use, with use of the most commonly abused legal substance alcohol as an example of the latter. Method Well‐known indices of disordered social media use, risky or problematic alcohol use, and the personality traits alexithymia, reward sensitivity, narcissism, and impulsivity were administered online to 143 men and women aged 18–35-years who were regular users of social media. The traits examined had previously been linked to substance misuse for a variety of substances, including alcohol, as presumed predisposing factors. Results After controlling for age, gender, and social desirability in hierarchical regressions, disordered social media use was predicted by narcissism, reward sensitivity, and impulsivity, whereas risky alcohol use was predicted by narcissism, alexithymia, and impulsivity. The ability of narcissism to predict disordered social media use was mediated by reward sensitivity, which was not the case for risky drinking. Conclusions Present results point to similarities and differences in addiction‐linked traits when comparing disordered social media use to risky or problematic substance use
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