3,975 research outputs found

    Thiemann transform for gravity with matter fields

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    The generalised Wick transform discovered by Thiemann provides a well-established relation between the Euclidean and Lorentzian theories of general relativity. We extend this Thiemann transform to the Ashtekar formulation for gravity coupled with spin-1/2 fermions, a non-Abelian Yang-Mills field, and a scalar field. It is proved that, on functions of the gravitational and matter phase space variables, the Thiemann transform is equivalent to the composition of an inverse Wick rotation and a constant complex scale transformation of all fields. This result holds as well for functions that depend on the shift vector, the lapse function, and the Lagrange multipliers of the Yang-Mills and gravitational Gauss constraints, provided that the Wick rotation is implemented by means of an analytic continuation of the lapse. In this way, the Thiemann transform is furnished with a geometric interpretation. Finally, we confirm the expectation that the generator of the Thiemann transform can be determined just from the spin of the fields and give a simple explanation for this fact.Comment: LaTeX 2.09, 14 pages, no figure

    Understanding of the Renormalization Program in a mathematically Rigorous Framework and an Intrinsic Mass Scale

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    we show there exists a mathematically consistent framework in which the Renormalization Program can be understood in a natural manner. The framework does not require any violations of mathematical rigor usually associated with the Renormalization program. We use the framework of the non-local field theories [these carry a finite mass scale (\Lambda)]and set up a finite perturbative program. We show how this program leads to the perturbation series of the usual renormalization program [except one difference] if the series is restructured .We further show that the comparison becomes possible if there exists a finite mass scale (\Lambda), with certain properties, in the Quantum Field theory [which we take to be the scale present in the nonlocal theory]. We give a way to estimate the scale (\Lambda). We also show that the finite perturbation program differs from the usual renormalization program by a term; which we propose can also be used to put a bound on (\Lambda).Comment: 19 pages, a missing equation added,a reference added and a few typos correcte

    Retrieving fin-de-siècle women poets: the transformative myths, fragments and voices of Webster, Blind and Levy

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    The critical recuperation of late nineteenth-century women poets, most still waiting in the margins of the literary canon, has owed significantly to the renovated interest and study of the poetical works of Augusta Webster, Mathilde Blind and Amy Levy (1860-90) by the postmodern reader. One of the reasons for this ‘salvage’ may be that they represent and embody the profound and extraordinary changes encompassing the British fin-de-siècle, in which the transition from the Victorians to the Moderns implied the transformation or reconfiguration of certain myths or (hi)stories and the critical re-use or ‘recycling’ of major literary forms. If, for Webster and Blind, involvement in radical politics (namely, feminism and socialism) certainly implied a stance as outsiders, Blind and Levy were even more set apart by their foreignness, with Levy’s different religion and sexuality increasing the distance even further. With recourse to close reading and cultural critique, this paper will analyse how these three women poets re-use fragments (‘verbal ruins’) of national and international history, as well as classic myth, in order to question and transform the images and representations of man and woman in their respective connections with the world. It will demonstrate that while Webster’s poetry (Dramatic Studies of 1866 and Portraits of 1870) is firmly grounded on social demands and the exploration and dramatization of the nature of female experience, Blind’s epic and dramatic verse (The Ascent of Man of 1889 and Dramas in Miniature of 1891) creates new myths of human destiny, reclaiming the Poet’s role as the singer of the age’s scientific deeds, and Levy’s lyrics (Xantippe of 1881 and A Minor Poet of 1884) signal the New Woman poet’s role as victim of the pressures of emancipation. With the support of critics as Isobel Armstrong, Helen Groth and Angela Leighton, the paper will furthermore discuss the way in which these poets explore the selves that women inherit and create and the languages that re-define them, often through the expansive, public forms of dramatic and narrative verse; through these hybrid and fragmentary forms, Webster, Blind and Levy literally give voice to unspeakable feelings and situations, in which the anomalous and marginal are made central.info:eu-repo/semantics/acceptedVersio

    Diffeomorphism on Horizon as an Asymptotic Isometry of Schwarzschild Black Hole

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    It is argued that the diffeomorphism on the horizontal sphere can be regarded as a nontrivial asymptotic isometry of the Schwarzschild black hole. We propose a new boundary condition of asymptotic metrics near the horizon and show that the condition admits the local time-shift and diffeomorphism on the horizon as the asymptotic symmetry.Comment: 18 pages, no figures, corrected some typo

    Numerical study of a non-equilibrium interface model

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    We have carried out extensive computer simulations of one-dimensional models related to the low noise (solid-on-solid) non-equilibrium interface of a two dimensional anchored Toom model with unbiased and biased noise. For the unbiased case the computed fluctuations of the interface in this limit provide new numerical evidence for the logarithmic correction to the subnormal L^(1/2) variance which was predicted by the dynamic renormalization group calculations on the modified Edwards-Wilkinson equation. In the biased case the simulations are in close quantitative agreement with the predictions of the Collective Variable Approximation (CVA), which gives the same L^(2/3) behavior of the variance as the KPZ equation.Comment: 15 pages revtex, 4 Postscript Figure

    Critical Exponents of the Three Dimensional Random Field Ising Model

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    The phase transition of the three--dimensional random field Ising model with a discrete (±h\pm h) field distribution is investigated by extensive Monte Carlo simulations. Values of the critical exponents for the correlation length, specific heat, susceptibility, disconnected susceptibility and magnetization are determined simultaneously via finite size scaling. While the exponents for the magnetization and disconnected susceptibility are consistent with a first order transition, the specific heat appears to saturate indicating no latent heat. Sample to sample fluctuations of the susceptibilty are consistent with the droplet picture for the transition.Comment: Revtex, 10 pages + 4 figures included as Latex files and 1 in Postscrip

    Smoothed Particle Hydrodynamics for Relativistic Heavy Ion Collisions

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    The method of smoothed particle hydrodynamics (SPH) is developped appropriately for the study of relativistic heavy ion collision processes. In order to describe the flow of a high energy but low baryon number density fluid, the entropy is taken as the SPH base. We formulate the method in terms of the variational principle. Several examples show that the method is very promising for the study of hadronic flow in RHIC physics.Comment: 14 pages, 8figure

    The Quantized O(1,2)/O(2)×Z2O(1,2)/O(2)\times Z_2 Sigma Model Has No Continuum Limit in Four Dimensions. I. Theoretical Framework

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    The nonlinear sigma model for which the field takes its values in the coset space O(1,2)/O(2)×Z2O(1,2)/O(2)\times Z_2 is similar to quantum gravity in being perturbatively nonrenormalizable and having a noncompact curved configuration space. It is therefore a good model for testing nonperturbative methods that may be useful in quantum gravity, especially methods based on lattice field theory. In this paper we develop the theoretical framework necessary for recognizing and studying a consistent nonperturbative quantum field theory of the O(1,2)/O(2)×Z2O(1,2)/O(2)\times Z_2 model. We describe the action, the geometry of the configuration space, the conserved Noether currents, and the current algebra, and we construct a version of the Ward-Slavnov identity that makes it easy to switch from a given field to a nonlinearly related one. Renormalization of the model is defined via the effective action and via current algebra. The two definitions are shown to be equivalent. In a companion paper we develop a lattice formulation of the theory that is particularly well suited to the sigma model, and we report the results of Monte Carlo simulations of this lattice model. These simulations indicate that as the lattice cutoff is removed the theory becomes that of a pair of massless free fields. Because the geometry and symmetries of these fields differ from those of the original model we conclude that a continuum limit of the O(1,2)/O(2)×Z2O(1,2)/O(2)\times Z_2 model which preserves these properties does not exist.Comment: 25 pages, no figure

    Ultra-High Energy Neutrino Fluxes: New Constraints and Implications

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    We apply new upper limits on neutrino fluxes and the diffuse extragalactic component of the GeV gamma-ray flux to various scenarios for ultra high energy cosmic rays and neutrinos. As a result we find that extra-galactic top-down sources can not contribute significantly to the observed flux of highest energy cosmic rays. The Z-burst mechanism where ultra-high energy neutrinos produce cosmic rays via interactions with relic neutrinos is practically ruled out if cosmological limits on neutrino mass and clustering apply.Comment: 10 revtex pages, 9 postscript figure

    Challenging SO(10) SUSY GUTs with family symmetries through FCNC processes

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    We perform a detailed analysis of the SO(10) SUSY GUT model with D3 family symmetry of Dermisek and Raby (DR). The model is specified in terms of 24 parameters and predicts, as a function of them, the whole MSSM set of parameters at low energy scales. Concerning the SM subset of such parameters, the model is able to give a satisfactory description of the quark and lepton masses, of the PMNS matrix and of the CKM matrix. We perform a global fit to the model, including flavour changing neutral current (FCNC) processes Bs --> mu+ mu-, B --> Xs gamma, B --> Xs l+ l- and the B(d,s) - bar B(d,s) mass differences Delta M(d,s) as well as the flavour changing (FC) process B+ --> tau+ nu. These observables provide at present the most sensitive probe of the SUSY mass spectrum and couplings predicted by the model. Our analysis demonstrates that the simultaneous description of the FC observables in question represents a serious challenge for the DR model, unless the masses of the scalars are moved to regions which are problematic from the point of view of naturalness and probably beyond the reach of the LHC. We emphasize that this problem could be a general feature of SUSY GUT models with third generation Yukawa unification and weak-scale minimal flavour violation.Comment: 1 + 37 pages, 5 figures, 11 tables. v3: minor typos fixed. Matches JHEP published versio
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