19,654 research outputs found
Hawking temperature from scattering off the charged 2D black hole
The charged 2D black hole is visualized as presenting an potential barrier
to on-coming tachyon wave. Since this takes the complicated
form, an approximate form is used for scattering analysis. We
calculate the reflection and transmission coefficients for scattering of
tachyon off the charged 2D black hole. The Hawking temperature is also derived
from the reflection coefficient by Bogoliubov transformation. In the limit of
, we recover the Hawking temperature of the 2D dilaton black hole.Comment: 12 pages 3 figures, RevTeX, to obtain figures contact author
([email protected]
Quantization of spontaneously broken gauge theory based on the BFT-BFV Formalism
We quantize the spontaneously broken abelian U(1) Higgs model by using the
improved BFT and BFV formalisms. We have constructed the BFT physical fields,
and obtain the first class observables including the Hamiltonian in terms of
these fields. We have also explicitly shown that there are exact form
invariances between the second class and first class quantities. Then,
according to the BFV formalism, we have derived the corresponding Lagrangian
having U(1) gauge symmetry. We also discuss at the classical level how one
easily gets the first class Lagrangian from the symmetry-broken second class
Lagrangian.Comment: 16 pages, latex, final version published in Mod. Phys. Lett.
Holography of the Conformal Window
Inspired by the model of Jarvinen and Kiritsis, we present a simple
holographic model for the on set of chiral symmetry breaking at the edge of the
conformal window in QCD in the Veneziano limit. Our most naive model enforces
the QCD two loop running coupling on a D3/D7 holographic brane system. The mass
of the holographic field, describing the chiral condensate in the model, is
driven below the BF bound when the running is sufficiently strong, triggering
chiral symmetry breaking for N_f/N_c<2.9. This model though contains too great
a remnant of supersymmetry and does not correctly encode the perturbative
anomalous dimensions of QCD. In a second model we impose the QCD anomalous
dimension result and find chiral symmetry breaking sets in for N_f/N_c=4 at a
BKT-type phase transition. In this case the transition is triggered when the
anomalous dimension of the mass operator \gamma_m=1.Comment: 10 pages, 2 figures, v2: minor corrections, improved Figure
Propagating waves in an extremal black string
We investigate the black string in the context of the string theories. It is
shown that the graviton is the only propagating mode in the (2+1)--dimensional
extremal black string background. Both the dilation and axion turn out to be
non-propagating modes.Comment: Minor corrections, 11 pages in ReVTeX, no figure
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