419 research outputs found

    Boundary Bound States in Affine Toda Field Theory

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    We demonstrate that the generalization of the Coleman-Thun mechanism may be applied to the situation, when considering scattering processes in 1+1-dimensions in the presence of reflecting boundaries. For affine Toda field theories we find that the binding energies of the bound states are always half the sum over a set of masses having the same colour with respect to the bicolouration of the Dynkin diagram. For the case of E6E_6-affine Toda field theory we compute explicitly the spectrum of all higher boundary bound states. The complete set of states constitutes a closed bootstrap.Comment: 16 p., Late

    Evaluating Sustainable Aspects of Hazardous Waste Remediation

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    The main objective of the research presented herein is to be a major contributor to the current international initiative to advance sustainability assessments for remediation projects by integrating methodologies from the environmental economics and social science disciplines. More specifically, the study aims to address some of the knowledge gaps related to conducting a comprehensive sustainability assessment for a remediation project. These knowledge gaps include: (1) there are few studies that include sustainability assessments of the variety of techniques and technologies implemented during site characterization; (2) the majority of sustainable remediation publications and assessment tools focus on evaluating the environmental impact of a contaminated site’s life cycle and minimally, if at all, on related socio-economic impacts; and (3) the role of risk perception in stakeholder engagement has not been explored in existing sustainable remediation frameworks. Chapters 2 through 4 presents a societal cost analysis methodology to quantify global socio-economic impacts arising from cleanup activity by monetizing the emissions and energy consumption through the integration of the social cost of environmental metrics. The results of environmental footprint and life cycle assessment evaluations conducted at various stages throughout the project life cycle were used as the basis for the societal cost analysis. Chapter 5 presents a survey developed and implemented to identify risk perception factors that influenced residents’ level of participation in risk management activities conducted by the local health department. Based on the case study evaluations presented herein, it can be concluded that the integration of methodologies from the environmental economics and social science disciplines into existing sustainable remediation frameworks results in a more comprehensive evaluation of triple bottom line impacts, a reduction in emissions and resources consumed during site activities, efficient use of financial resources, and a maximization of benefits to stakeholders, in particular the community

    The Gross-Neveu Model from String Theory

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    We study an intersecting D-brane model which at low energies describes (1+1)-dimensional chiral fermions localized at defects on a stack of N_c D4-branes. Fermions at different defects interact via exchange of massless (4+1)-dimensional fields. At weak coupling this interaction gives rise to the Gross-Neveu (GN) model and can be studied using field theoretic techniques. At strong coupling one can describe the system in terms of probe branes propagating in a curved background in string theory. The chiral symmetry is dynamically broken at zero temperature and is restored above a critical temperature T_c which depends on the coupling. The phase transition at T_c is first order at strong coupling and second order at weak coupling.Comment: 32 pages, harvmac (b

    Mass generation without phase coherence in the Chiral Gross-Neveu Model at finite temperature and small N in 2+1 dimensions

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    The chiral Gross-Neveu model is one of the most popular toy models for QCD. In the past, it has been studied in detail in the large-N limit. In this paper we study its small-N behavior at finite temperature in 2+1 dimensions. We show that at small N the phase diagram of this model is {\it principally} different from its behavior at NN\to \infty. We show that for a small number NN of fermions the model possesses two characteristic temperatures TKTT_{KT} and TT^*. That is, at small N, along with a quasiordered phase 0<T<TKT0<T<T_{KT} the system possesses a very large region of precursor fluctuations TKT<T<TT_{KT}<T<T^* which disappear only at a temperature TT^*, substantially higher than the temperature TKTT_{KT} of Kosterlitz-Thouless transition.Comment: a factor 2 corrected. An extended discussion of similarities and differences of low-N behavior of the chiral GN model and various models of superconductivity is currently in preparation and will be presented in additional articl

    Dynamical correlations and quantum phase transition in the quantum Potts model

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    We present a detailed study of the finite temperature dynamical properties of the quantum Potts model in one dimension.Quasiparticle excitations in this model have internal quantum numbers, and their scattering matrix {\gf deep} in the gapped phases is shown to take a simple {\gf exchange} form in the perturbative regimes. The finite temperature correlation functions in the quantum critical regime are determined using conformal invariance, while {\gf far from the quantum critical point} we compute the decay functions analytically within a semiclassical approach of Sachdev and Damle [K. Damle and S. Sachdev, Phys. Rev. B \textbf{57}, 8307 (1998)]. As a consequence, decay functions exhibit a {\em diffusive character}. {\gf We also provide robust arguments that our semiclassical analysis carries over to very low temperatures even in the vicinity of the quantum phase transition.} Our results are also relevant for quantum rotor models, antiferromagnetic chains, and some spin ladder systems.Comment: 18 PRB pages added correction

    Bethe ansatz solution of the anisotropic correlated electron model associated with the Temperley-Lieb algebra

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    A recently proposed strongly correlated electron system associated with the Temperley-Lieb algebra is solved by means of the coordinate Bethe ansatz for periodic and closed boundary conditions.Comment: 21 page

    Haldane limits via Lagrangian embeddings

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    In the present paper we revisit the so-called Haldane limit, i.e. a particular continuum limit, which leads from a spin chain to a sigma model. We use the coherent state formulation of the path integral to reduce the problem to a semiclassical one, which leads us to the observation that the Haldane limit is closely related to a Lagrangian embedding into the classical phase space of the spin chain. Using this property, we find a spin chain whose limit produces a relativistic sigma model with target space the manifold of complete flags U(N)/U(1)^N. We discuss possible other future applications of Lagrangian/isotropic embeddings in this context.Comment: 29 pages, 2 figure
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