260 research outputs found

    Coset Constructions in Chern-Simons Gauge Theory

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    Coset constructions in the framework of Chern-Simons topological gauge theories are studied. Two examples are considered: models of the types U(1)p×U(1)qU(1)p+qU(1)pq(p+q){U(1)_p\times U(1)_q\over U(1)_{p+q}}\cong U(1)_{pq(p+q)} with pp and qq coprime integers, and SU(2)m×SU(2)1SU(2)m+1{SU(2)_m\times SU(2)_1\over SU(2)_{m+1}}. In the latter case it is shown that the Chern-Simons wave functionals can be identified with t he characters of the minimal unitary models, and an explicit representation of the knot (Verlinde) operators acting on the space of c<1c<1 characters is obtained.Comment: 15 page

    Polynomials for Torus Links from Chern-Simons Gauge Theories

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    Invariant polynomials for torus links are obtained in the framework of the Chern-Simons topological gauge theory. The polynomials are computed as vacuum expectation values on the three-sphere of Wilson line operators representing the Verlinde algebra of the corresponding rational conformal field theory. In the case of the SU(2)SU(2) gauge theory our results provide explicit expressions for the Jones polynomial as well as for the polynomials associated to the NN-state (N>2N>2) vertex models (Akutsu-Wadati polynomials). By means of the Chern-Simons coset construction, the minimal unitary models are analyzed, showing that the corresponding link invariants factorize into two SU(2)SU(2) polynomials. A method to obtain skein rules from the Chern-Simons knot operators is developed. This procedure yields the eigenvalues of the braiding matrix of the corresponding conformal field theory.Comment: 50 page

    Higgs Boson Production in Association with Three Jets

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    The scattering amplitudes for Higgs + 5 partons are computed, with the Higgs boson produced via gluon fusion in the large top-quark mass limit. A parton-level analysis of Higgs + 3 jet production via gluon fusion and via weak-boson fusion is presented, and the effectiveness of a central-jet veto is analysed.Comment: 26 pages, 4 Postscript figures, uses JHEP3.cl

    A Survey of Finite Algebraic Geometrical Structures Underlying Mutually Unbiased Quantum Measurements

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    The basic methods of constructing the sets of mutually unbiased bases in the Hilbert space of an arbitrary finite dimension are discussed and an emerging link between them is outlined. It is shown that these methods employ a wide range of important mathematical concepts like, e.g., Fourier transforms, Galois fields and rings, finite and related projective geometries, and entanglement, to mention a few. Some applications of the theory to quantum information tasks are also mentioned.Comment: 20 pages, 1 figure to appear in Foundations of Physics, Nov. 2006 two more references adde

    Jet angular correlation in vector-boson fusion processes at hadron colliders

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    Higgs boson and massive-graviton productions in association with two jets via vector-boson fusion (VBF) processes and their decays into a vector-boson pair at hadron colliders are studied. They include scalar and tensor boson production processes via weak-boson fusion in quark-quark collisions, gluon fusion in quark-quark, quark-gluon and gluon-gluon collisions, as well as their decays into a pair of weak bosons or virtual gluons which subsequently decay into ˉ\ell\bar\ell, qqˉq\bar q or gggg. We give the helicity amplitudes explicitly for all the VBF subprocesses, and show that the VBF amplitudes dominate the exact matrix elements not only for the weak-boson fusion processes but also for all the gluon fusion processes when appropriate selection cuts are applied, such as a large rapidity separation between two jets and a slicing cut for the transverse momenta of the jets. We also show that our off-shell vector-boson current amplitudes reduce to the standard quark and gluon splitting amplitudes with appropriate gluon-polarization phases in the collinear limit. Nontrivial azimuthal angle correlations of the jets in the production and in the decay of massive spin-0 and -2 bosons are manifestly expressed as the quantum interference among different helicity states of the intermediate vector-bosons. Those correlations reflect the spin and the CP nature of the Higgs bosons and the massive gravitons.Comment: 47 pages, 7 figures, 10 tables; references added, version to appear in JHE

    Self-organized criticality in deterministic systems with disorder

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    Using the Bak-Sneppen model of biological evolution as our paradigm, we investigate in which cases noise can be substituted with a deterministic signal without destroying Self-Organized Criticality (SOC). If the deterministic signal is chaotic the universality class is preserved; some non-universal features, such as the threshold, depend on the time correlation of the signal. We also show that, if the signal introduced is periodic, SOC is preserved but in a different universality class, as long as the spectrum of frequencies is broad enough.Comment: RevTex, 8 pages, 8 figure

    A VALUE PLATFORM ANALYSIS PERSPECTIVE ON CUSTOMER ACCESS INFORMATION TECHNOLOGY

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    Customer access information technologies (CAITs) provide a link between a firm and its customers. Firms invest in CAITs to reduce costs, increase revenues and market share, lock in existing customers and capture new ones. These benefits, however, are notoriously difficult to measure. This paper proposes an evaluative method for CAlT deployment called value platform analysis, that is based on a conceptual model drawn from the theory of retail outlet deployment in marketing science. The model focuses on the impact of CAIT features and environmental features on transactions generated by the CAIT. Specific econometric models are developed for deployment. Hypotheses regarding the likely impact of automated teller machine (ATM) location design choices and environmental features on ATM transactions are evaluated. The results indicate that there are a number of key features influencing ATM performance. Two distinct ATM deployment scenarios emerge: one for servicing a bank's own customers, and another for providing transaction services for customers for a fee.Information Systems Working Papers Serie

    Red Queen Coevolution on Fitness Landscapes

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    Species do not merely evolve, they also coevolve with other organisms. Coevolution is a major force driving interacting species to continuously evolve ex- ploring their fitness landscapes. Coevolution involves the coupling of species fit- ness landscapes, linking species genetic changes with their inter-specific ecological interactions. Here we first introduce the Red Queen hypothesis of evolution com- menting on some theoretical aspects and empirical evidences. As an introduction to the fitness landscape concept, we review key issues on evolution on simple and rugged fitness landscapes. Then we present key modeling examples of coevolution on different fitness landscapes at different scales, from RNA viruses to complex ecosystems and macroevolution.Comment: 40 pages, 12 figures. To appear in "Recent Advances in the Theory and Application of Fitness Landscapes" (H. Richter and A. Engelbrecht, eds.). Springer Series in Emergence, Complexity, and Computation, 201

    Distributed flow optimization and cascading effects in weighted complex networks

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    We investigate the effect of a specific edge weighting scheme (kikj)β\sim (k_i k_j)^{\beta} on distributed flow efficiency and robustness to cascading failures in scale-free networks. In particular, we analyze a simple, yet fundamental distributed flow model: current flow in random resistor networks. By the tuning of control parameter β\beta and by considering two general cases of relative node processing capabilities as well as the effect of bandwidth, we show the dependence of transport efficiency upon the correlations between the topology and weights. By studying the severity of cascades for different control parameter β\beta, we find that network resilience to cascading overloads and network throughput is optimal for the same value of β\beta over the range of node capacities and available bandwidth

    Flavor changing single top quark production channels at e^+e^- colliders in the effective Lagrangian description

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    We perform a global analysis of the sensitivity of LEP2 and e^+e^- colliders with a c.m. energy in the range 500 - 2000 GeV to new flavor-changing single top quark production in the effective Lagrangian approach. The processes considered are sensitive to new flavor-changing effective vertices such as Ztc, htc, four-Fermi tcee contact terms as well as a right-handed Wtb coupling. We show that e^+ e^- colliders are most sensitive to the physics responsible for the contact tcee vertices. For example, it is found that the recent data from the 189 GeV LEP2 run can be used to rule out any new flavor physics that can generate these four-Fermi operators up to energy scales of \Lambda > 0.7 - 1.4 TeV, depending on the type of the four-Fermi interaction. We also show that a corresponding limit of \Lambda > 1.3 - 2.5 and \Lambda > 17 - 27 TeV can be reached at the future 200 GeV LEP2 run and a 1000 GeV e^+e^- collider, respectively. We note that these limits are much stronger than the typical limits which can be placed on flavor diagonal four-Fermi couplings. Similar results hold for \mu^+\mu^- colliders and for tu(bar) associated production. Finally we briefly comment on the necessity of measuring all flavor-changing effective vertices as they can be produced by different types of heavy physics.Comment: 34 pages, plain latex, 7 figures embadded in the text using epsfig. Added new references and discussions regarding their relevance to the paper. Added more comments on the comparison between flavor-changing and flavor-diagonal contact terms and on the importance of measuring the Ztc verte
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