7,262 research outputs found

    New critical frontiers for the Potts and percolation models

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    We obtain the critical threshold for a host of Potts and percolation models on lattices having a structure which permits a duality consideration. The consideration generalizes the recently obtained thresholds of Scullard and Ziff for bond and site percolation on the martini and related lattices to the Potts model and to other lattices.Comment: 9 pages, 5 figure

    Selfduality for coupled Potts models on the triangular lattice

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    We present selfdual manifolds for coupled Potts models on the triangular lattice. We exploit two different techniques: duality followed by decimation, and mapping to a related loop model. The latter technique is found to be superior, and it allows to include three-spin couplings. Starting from three coupled models, such couplings are necessary for generating selfdual solutions. A numerical study of the case of two coupled models leads to the identification of novel critical points

    Tax evasion dynamics and Zaklan model on Opinion-dependent Network

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    Within the context of agent-based Monte-Carlo simulations, we study the well-known majority-vote model (MVM) with noise applied to tax evasion on Stauffer-Hohnisch-Pittnauer (SHP) networks. To control the fluctuations for tax evasion in the economics model proposed by Zaklan, MVM is applied in the neighborhood of the critical noise qcq_{c} to evolve the Zaklan model. The Zaklan model had been studied recently using the equilibrium Ising model. Here we show that the Zaklan model is robust because this can be studied besides using equilibrium dynamics of Ising model also through the nonequilibrium MVM and on various topologies giving the same behavior regardless of dynamic or topology used here.Comment: 14 page, 4 figure

    Non-nequilibrium model on Apollonian networks

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    We investigate the Majority-Vote Model with two states (−1,+1-1,+1) and a noise qq on Apollonian networks. The main result found here is the presence of the phase transition as a function of the noise parameter qq. We also studies de effect of redirecting a fraction pp of the links of the network. By means of Monte Carlo simulations, we obtained the exponent ratio γ/ν\gamma/\nu, β/ν\beta/\nu, and 1/ν1/\nu for several values of rewiring probability pp. The critical noise was determined qcq_{c} and U∗U^{*} also was calculated. The effective dimensionality of the system was observed to be independent on pp, and the value Deff≈1.0D_{eff} \approx1.0 is observed for these networks. Previous results on the Ising model in Apollonian Networks have reported no presence of a phase transition. Therefore, the results present here demonstrate that the Majority-Vote Model belongs to a different universality class as the equilibrium Ising Model on Apollonian Network.Comment: 5 pages, 5 figure

    Extended surface disorder in the quantum Ising chain

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    We consider random extended surface perturbations in the transverse field Ising model decaying as a power of the distance from the surface towards a pure bulk system. The decay may be linked either to the evolution of the couplings or to their probabilities. Using scaling arguments, we develop a relevance-irrelevance criterion for such perturbations. We study the probability distribution of the surface magnetization, its average and typical critical behaviour for marginal and relevant perturbations. According to analytical results, the surface magnetization follows a log-normal distribution and both the average and typical critical behaviours are characterized by power-law singularities with continuously varying exponents in the marginal case and essential singularities in the relevant case. For enhanced average local couplings, the transition becomes first order with a nonvanishing critical surface magnetization. This occurs above a positive threshold value of the perturbation amplitude in the marginal case.Comment: 15 pages, 10 figures, Plain TeX. J. Phys. A (accepted

    Critical and Tricritical Hard Objects on Bicolorable Random Lattices: Exact Solutions

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    We address the general problem of hard objects on random lattices, and emphasize the crucial role played by the colorability of the lattices to ensure the existence of a crystallization transition. We first solve explicitly the naive (colorless) random-lattice version of the hard-square model and find that the only matter critical point is the non-unitary Lee-Yang edge singularity. We then show how to restore the crystallization transition of the hard-square model by considering the same model on bicolored random lattices. Solving this model exactly, we show moreover that the crystallization transition point lies in the universality class of the Ising model coupled to 2D quantum gravity. We finally extend our analysis to a new two-particle exclusion model, whose regular lattice version involves hard squares of two different sizes. The exact solution of this model on bicolorable random lattices displays a phase diagram with two (continuous and discontinuous) crystallization transition lines meeting at a higher order critical point, in the universality class of the tricritical Ising model coupled to 2D quantum gravity.Comment: 48 pages, 13 figures, tex, harvmac, eps

    Negotiation, bargaining, and discounts:generating WoM and local tourism development at the Tabriz bazaar, Iran

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    This paper examines the effects of negotiation intention, bargaining propensity, and discount satisfaction on word-of-mouth (WoM) behaviours for tourists visiting Tabriz bazaar, Iran. Data from 615-survey respondents highlight that tourists are motivated to conduct WoM behaviour when they are experientially satisfied with the opportunity to negotiate and bargain, and when they are satisfied with the discount they receive. This paper makes theoretical contributions to social exchange theory and presents managerial implications for policy-makers to generate tourism development

    Screening and Breeding for Bermudagrass Stem Maggot (BSM) Resistance Using U.S. Bermudagrass Germplasm

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    Bermudagrass (Cynodon sp.) is an important perennial forage grass grown in many parts of the world. Bermudagrass Stem Maggot (BSM) (Atherigona reversura Villeneuve) is an insect pest that reduces forage yield and nutritive value if it is not controlled. The pest, native to SE Asia, was first documented in North America in 2009 and is now considered invasive. A collection of over 300 forage bermudagrass accessions was evaluated in the field for susceptibility to BSM in 2014 and 2015. Tolerant lines and susceptible checks were then evaluated for yield loss due to BSM in a replicated field study by comparing insecticide-sprayed plots to unsprayed plots in Tifton, GA starting in 2016 continuing through the summer of 2019. For mid to late summer harvests during 2017, BSM reduced yield of Alicia and Russell by over 40% and Tifton 85 by up to 35%. However, tolerant accessions exhibited less than 10% yield loss and had dry matter yields comparable to Tifton 85. Nutritive value will also be assessed. These accessions will be further evaluated and used in plant breeding

    Perfection of materials technology for producing improved Gunn-effect devices

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    Chemical vapor deposition system for improved Gunn effect devices using arsenic chloride 3 metho

    Conformal invariance studies of the Baxter-Wu model and a related site-colouring problem

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    The partition function of the Baxter-Wu model is exactly related to the generating function of a site-colouring problem on a hexagonal lattice. We extend the original Bethe ansatz solution of these models in order to obtain the eigenspectra of their transfer matrices in finite geometries and general toroidal boundary conditions. The operator content of these models are studied by solving numerically the Bethe-ansatz equations and by exploring conformal invariance. Since the eigenspectra are calculated for large lattices, the corrections to finite-size scaling are also calculated.Comment: 12 pages, latex, to appear in J. Phys. A: Gen. Mat
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