3,975 research outputs found
Thiemann transform for gravity with matter fields
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
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
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
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
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
The phase transition of the three--dimensional random field Ising model with
a discrete () 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
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 Sigma Model Has No Continuum Limit in Four Dimensions. I. Theoretical Framework
The nonlinear sigma model for which the field takes its values in the coset
space 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 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 model which preserves
these properties does not exist.Comment: 25 pages, no figure
Ultra-High Energy Neutrino Fluxes: New Constraints and Implications
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
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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