66 research outputs found
Redefining B-twisted topological sigma models
A recently proposed variation on the usual procedure to perform the
topological B-twist in rigid models is applied to the case of the model on a K\"ahler manifold. This leads to an alternative description of
Witten's topological model, which allows for a proper BRST
interpretation and ghost number assignement. We also show that the auxiliary
fields, which are responsible for the off shell closure of the algebra,
play an important role in our construction.Comment: one reference adde
A study of the odes of John Keats
A number of critics have viewed the odes of Keats as fitting into a neat pattern of thought. One must bear in mind that the poet was young and admittedly quite changeable. Clearly these works are distinct from each other, Yet, just as clearly there are common threads in all of Keats\u27s odes
Order parameter fluctuations in the holographic superconductor
We investigate the effect of order parameter fluctuations in the holographic
superconductor. In particular, using a fully backreacted bulk geometry, the
intrinsic spectral functions of the order parameter in both the normal and the
superconducting phase are computed. We also present a vector-like large-
version of the Ginzburg-Landau model that accurately describes our
long-wavelength results in both phases. The large- limit of the latter model
explains why the Higgs mode and the second-sound mode are not present in the
spectral functions. Our results indicate that the holographic superconductor
describes a relativistic multi-component superfluid in the universal regime of
the BEC-BCS crossover.Comment: 21 pages, 15 figures; version accepted for publicatio
The regularized BRST Jacobian of pure Yang-Mills theory
The Jacobian for infinitesimal BRST transformations of path integrals for
pure Yang-Mills theory, viewed as a matrix \unity +\Delta J in the space of
Yang-Mills fields and (anti)ghosts, contains off-diagonal terms. Naively, the
trace of vanishes, being proportional to the trace of the structure
constants. However, the consistent regulator \cR, constructed from a general
method, also contains off-diagonal terms. An explicit computation demonstrates
that the regularized Jacobian Tr\ \Delta J\exp -\cR /M^2 for is the variation of a local counterterm, which we give. This is a
direct proof at the level of path integrals that there is no BRST anomaly.Comment: 12 pages, latex, CERN-TH.6541/92, KUL-TF-92/2
An alternative BRST operator for topological Landau-Ginzburg models
We propose a new BRST operator for the B-twist of N=2 Landau-Ginzburg (LG) models. It solves the problem of the fractional ghost numbers of Vafa's old BRST operator and shows how the model is obtained by gauge fixing a zero action. An essential role is played by the anti-BRST operator,which is given by one of the supersymmetries of the N=2 algebra. Its presence is needed in proving that the model is indeed a topological field theory. The space of physical observables, defined by taking the anti-BRST cohomology in the BRST cohomology groups, is unchanged
Four-dimensional black hole entropy from F-theory
We study the central charges and levels of a two-dimensional
superconformal field theory describing four-dimensional BPS black holes in
F-theory. These arise from D3-branes wrapping a curve in the base of an
elliptically fibered Calabi-Yau threefold times a circle, and probe a
transverse Taub-NUT space. The near horizon geometry of these D3-branes is
AdS, where is the NUT charge. Starting
from a six-dimensional supergravity effective action we compute
three-dimensional Chern-Simons terms to deduce the central charges and levels.
We find that it is crucial to integrate out an infinite tower of massive
Kaluza-Klein states on S to match the expected microscopic
results. The induced corrections turn out to contribute at leading order to the
central charges and levels, which in turn determine the black hole entropy.Comment: 44 pages; v2: minor typos correcte
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