The Experts below are selected from a list of 228 Experts worldwide ranked by ideXlab platform

Stefano Spirito - One of the best experts on this subject based on the ideXlab platform.

Paolo Antonelli - One of the best experts on this subject based on the ideXlab platform.

T. G. Steele - One of the best experts on this subject based on the ideXlab platform.

  • Direct single-instanton contributions to Finite-Energy sum rules
    Physics Letters B, 1998
    Co-Authors: A. S. Deakin, Victor Elias, Norman H. Fuchs, T. G. Steele
    Abstract:

    Instanton contributions to pseudoscalar Finite-Energy sum rules are extracted from the explicit single-instanton contribution to the pseudoscalar Laplace sum rule in the instanton liquid model.Comment: 10 pages, LaTeX, 2 postscript figure

  • Broad sub-continuum resonances and the case for Finite-Energy sum-rules
    European Physical Journal C, 1998
    Co-Authors: A. S. Deakin, Victor Elias, Amir H. Fariborz, T. G. Steele
    Abstract:

    There is a need to go beyond the narrow resonance approximation for QCD sum-rule channels which are likely to exhibit sensitivity to broad resonance structures. We discuss how the first two Laplace sum rules are altered when one goes beyond the narrow resonance approximation to include possible subcontinuum resonances with nonzero widths. We show that the corresponding first two Finite Energy sum rules are insensitive to the widths of such resonances, provided their peaks are symmetric and entirely below the continuum threshold. We also discuss the reduced sensitivity of the first two Finite Energy sum rules to higher dimensional condensates, and show these sum rules to be insensitive to dimension \(> 6\) condensates containing at least one \(\bar{q}q\) pair. We extract the direct single-instanton contribution to the \(F_1\) sum rule for the longitudinal component of the axial-vector correlation function from the known single-instanton contribution to the lowest Laplace sum rule for the pseudoscalar channel. Finally, we demonstrate how inclusion of this instanton contribution to the Finite-Energy sum rule leads to both a lighter quark mass and to more phenomenologically reasonable higher-mass-resonance contributions within the pseudoscalar channel.

  • Direct single-instanton contributions to Finite-Energy sum rules
    Physics Letters B, 1998
    Co-Authors: A. S. Deakin, Victor Elias, Norman H. Fuchs, T. G. Steele
    Abstract:

    Abstract Instanton contributions to pseudoscalar Finite-Energy sum rules are extracted from the explicit single-instanton contribution to the pseudoscalar Laplace sum rule in the instanton liquid model.

  • Finite Energy sum rules and instantons in the instanton liquid model
    Journal of Physics G, 1998
    Co-Authors: Victor Elias, T. G. Steele
    Abstract:

    We obtain the imaginary part of the direct single-instanton contribution to the pseudoscalar correlator, as defined by the appropriate dispersion relation, in order to derive an explicit integral representation for the instanton contribution to Finite Energy sum rules in the instanton liquid model.

  • Broad Sub-Continuum Resonances and the Case for Finite-Energy Sum-Rules
    arXiv: High Energy Physics - Phenomenology, 1997
    Co-Authors: A. S. Deakin, Victor Elias, Amir H. Fariborz, T. G. Steele
    Abstract:

    There is a need to go beyond the narrow resonance approximation for QCD sum-rule channels which are likely to exhibit sensitivity to broad resonance structures. We first discuss how the first two Laplace sum rules are altered when one goes beyond the narrow resonance approximation to include possible subcontinuum resonances with nonzero widths. We then show that the corresponding first two Finite Energy sum rules are insensitive to the widths of such resonances, provided their peaks are symmetric and entirely below the continuum threshold. We also discuss the reduced sensitivity of the first two Finite Energy sum rules to higher dimensional condensates, and show these sum rules to be insensitive to dimension > 6 condensates containing at least one q-bar q pair. We extract the direct single-instanton contribution to the F_1 sum rule for the longitudinal component of the axial-vector correlation function from the known single-instanton contribution to the lowest Laplace sum rule for the pseudoscalar channel. Finally, we demonstrate how inclusion of this instanton contribution to the Finite-Energy sum rule leads to both a lighter quark mass and to more phenomenologically reasonable higher-mass resonance contributions within the pseudoscalar channel.

O.v. Pavlovskiı̆ - One of the best experts on this subject based on the ideXlab platform.

Jean-luc Sauvageot - One of the best experts on this subject based on the ideXlab platform.

  • Variations in noncommutative potential theory: Finite Energy states, potentials and multipliers
    Transactions of the American Mathematical Society, 2015
    Co-Authors: Fabio Cipriani, Jean-luc Sauvageot
    Abstract:

    In this work we undertake an extension of various aspects of the potential theory of Dirichlet forms from locally compact spaces to noncommu- tative C � -algebras with trace. In particular we introduce Finite-Energy states, potentials and multipliers of Dirichlet spaces. We prove several results among which the celebrated Deny's embedding theorem and the Deny's inequality, the fact that the carre du champ of bounded potentials are Finite-Energy func- tionals and the relative supply of multipliers. 1. Introduction and description of the results. In the present work we develop further the potential theory of Dirichlet forms on noncommutative C ∗ -algebras with trace. We introduce and investigate Finite- Energy states, potentials and multipliers, objects naturally associated to Dirichlet spaces and which are meant to encode or reveal the geometric nature of the latter. In a companion work the results here obtained will be crucial to construct on C ∗ - algebras endowed with a Dirichlet form, the building blocks of a metric differential geometry (Dirac operators and Spectral Triples) and topological invariants (sum- mable Fredholm modules in K-homology) in the framework of the Noncommutative Geometry developed by A. Connes (Co). Classical potential theory, studying harmonic functions on Euclidean spaces R n , Finite-Energy measures and their potentials, was based on the properties of kernel |x − y| −1 , the so called Green function, to understood as the integral kernel of the

  • Variations in noncommutative potential theory: Finite Energy states, potentials and multipliers
    arXiv: Operator Algebras, 2012
    Co-Authors: Fabio Cipriani, Jean-luc Sauvageot
    Abstract:

    In this work we undertake an extension of various aspects of the potential theory of Dirichlet forms from locally compact spaces to noncommutative C*-algebras with trace. In particular we introduce Finite-Energy states, potentials and multipliers of Dirichlet spaces. We prove several results among which the celebrated Deny's embedding theorem and the Deny's inequality, the fact that the carre' du champ of bounded potentials are Finite-Energy functionals and the relative supply of multipliers.