435 research outputs found

    Exact multilocal renormalization on the effective action : application to the random sine Gordon model statics and non-equilibrium dynamics

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    We extend the exact multilocal renormalization group (RG) method to study the flow of the effective action functional. This important physical quantity satisfies an exact RG equation which is then expanded in multilocal components. Integrating the nonlocal parts yields a closed exact RG equation for the local part, to a given order in the local part. The method is illustrated on the O(N) model by straightforwardly recovering the η\eta exponent and scaling functions. Then it is applied to study the glass phase of the Cardy-Ostlund, random phase sine Gordon model near the glass transition temperature. The static correlations and equilibrium dynamical exponent zz are recovered and several new results are obtained. The equilibrium two-point scaling functions are obtained. The nonequilibrium, finite momentum, two-time t,tt,t' response and correlations are computed. They are shown to exhibit scaling forms, characterized by novel exponents λRλC\lambda_R \neq \lambda_C, as well as universal scaling functions that we compute. The fluctuation dissipation ratio is found to be non trivial and of the form X(qz(tt),t/t)X(q^z (t-t'), t/t'). Analogies and differences with pure critical models are discussed.Comment: 33 pages, RevTe

    Velocity-force characteristics of an interface driven through a periodic potential

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    We study the creep dynamics of a two-dimensional interface driven through a periodic potential using dynamical renormalization group methods. We find that the nature of weak-drive transport depends qualitatively on whether the temperature TT is above or below the equilibrium roughening transition temperature TcT_c. Above TcT_c, the velocity-force characteristics is Ohmic, with linear mobility exhibiting a jump discontinuity across the transition. For TTcT \le T_c, the transport is highly nonlinear, exhibiting an interesting crossover in temperature and weak external force FF. For intermediate drive, F>FF>F_*, we find near TcT_c^{-} a power-law velocity-force characteristics v(F)Fσv(F)\sim F^\sigma, with σ1t~\sigma-1\propto \tilde{t}, and well-below TcT_c, v(F)e(F/F)2t~v(F)\sim e^{-(F_*/F)^{2\tilde{t}}}, with t~=(1T/Tc)\tilde{t}=(1-T/T_c). In the limit of vanishing drive (FFF\ll F_*) the velocity-force characteristics crosses over to v(F)e(F0/F)v(F)\sim e^{-(F_0/F)}, and is controlled by soliton nucleation.Comment: 18 pages, submitted to Phys. Rev.

    A New Fuzzy Additive Noise Reduction Method

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    In this paper we present a new alternative noise reduction method for color images that were corrupted with additive Gaussian noise. We illustrate that color images have to be processed in a different way than most of the state-of-the-art methods. The proposed method consists of two sub-filters. The main concern of the first subfilter is to distinguish between local variations due to noise and local variations due to image structures such as edges. This is realized by using the color component distances instead of component differences as done by most current filters. The second subfilter is used as a complementary filter which especially preserves differences between the color components. This is realized by calculating the local differences in the red, green and blue environment separately. These differences are then combined to calculate the local estimation of the central pixel. Experimental results show the feasibility of the proposed approach

    Customer emotions in service failure and recovery encounters

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    Emotions play a significant role in the workplace, and considerable attention has been given to the study of employee emotions. Customers also play a central function in organizations, but much less is known about customer emotions. This chapter reviews the growing literature on customer emotions in employee–customer interfaces with a focus on service failure and recovery encounters, where emotions are heightened. It highlights emerging themes and key findings, addresses the measurement, modeling, and management of customer emotions, and identifies future research streams. Attention is given to emotional contagion, relationships between affective and cognitive processes, customer anger, customer rage, and individual differences

    Search for leptophobic Z ' bosons decaying into four-lepton final states in proton-proton collisions at root s=8 TeV

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    Search for black holes and other new phenomena in high-multiplicity final states in proton-proton collisions at root s=13 TeV

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    Search for high-mass diphoton resonances in proton-proton collisions at 13 TeV and combination with 8 TeV search

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    Search for heavy resonances decaying into a vector boson and a Higgs boson in final states with charged leptons, neutrinos, and b quarks

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    Search for Gravitational Waves Associated with Gamma-Ray Bursts Detected by Fermi and Swift during the LIGO-Virgo Run O3b

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    We search for gravitational-wave signals associated with gamma-ray bursts (GRBs) detected by the Fermi and Swift satellites during the second half of the third observing run of Advanced LIGO and Advanced Virgo (2019 November 1 15:00 UTC-2020 March 27 17:00 UTC). We conduct two independent searches: A generic gravitational-wave transients search to analyze 86 GRBs and an analysis to target binary mergers with at least one neutron star as short GRB progenitors for 17 events. We find no significant evidence for gravitational-wave signals associated with any of these GRBs. A weighted binomial test of the combined results finds no evidence for subthreshold gravitational-wave signals associated with this GRB ensemble either. We use several source types and signal morphologies during the searches, resulting in lower bounds on the estimated distance to each GRB. Finally, we constrain the population of low-luminosity short GRBs using results from the first to the third observing runs of Advanced LIGO and Advanced Virgo. The resulting population is in accordance with the local binary neutron star merger rate. © 2022. The Author(s). Published by the American Astronomical Society
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