16,358 research outputs found
Superspace Formulation for the BRST Quantization of the Chiral Schwinger Model
It has recently been shown that the Field Antifield quantization of anomalous
irreducible gauge theories with closed algebra can be represented in a BRST
superspace where the quantum action at one loop order, including the Wess
Zumino term, and the anomalies show up as components of the same superfield. We
show here how the Chiral Schwinger model can be represented in this
formulation.Comment: 11 pages, Late
Noncommutativity and Duality through the Symplectic Embedding Formalism
This work is devoted to review the gauge embedding of either commutative and
noncommutative (NC) theories using the symplectic formalism framework. To sum
up the main features of the method, during the process of embedding, the
infinitesimal gauge generators of the gauge embedded theory are easily and
directly chosen. Among other advantages, this enables a greater control over
the final Lagrangian and brings some light on the so-called "arbitrariness
problem". This alternative embedding formalism also presents a way to obtain a
set of dynamically dual equivalent embedded Lagrangian densities which is
obtained after a finite number of steps in the iterative symplectic process,
oppositely to the result proposed using the BFFT formalism. On the other hand,
we will see precisely that the symplectic embedding formalism can be seen as an
alternative and an efficient procedure to the standard introduction of the
Moyal product in order to produce in a natural way a NC theory. In order to
construct a pedagogical explanation of the method to the nonspecialist we
exemplify the formalism showing that the massive NC U(1) theory is embedded in
a gauge theory using this alternative systematic path based on the symplectic
framework. Further, as other applications of the method, we describe exactly
how to obtain a Lagrangian description for the NC version of some systems
reproducing well known theories. Naming some of them, we use the procedure in
the Proca model, the irrotational fluid model and the noncommutative self-dual
model in order to obtain dual equivalent actions for these theories. To
illustrate the process of noncommutativity introduction we use the chiral
oscillator and the nondegenerate mechanics
Axial Anomaly from the BPHZ regularized BV master equation
A BPHZ renormalized form for the master equation of the field antifiled (or
BV) quantization has recently been proposed by De Jonghe, Paris and Troost.
This framework was shown to be very powerful in calculating gauge anomalies. We
show here that this equation can also be applied in order to calculate a global
anomaly (anomalous divergence of a classically conserved Noether current),
considering the case of QED. This way, the fundamental result about the
anomalous contribution to the Axial Ward identity in standard QED (where there
is no gauge anomaly) is reproduced in this BPHZ regularized BV framework.Comment: 10 pages, Latex, minor changes in the reference
A photometric analysis of Abell 1689: two-dimensional multi-structure decomposition, morphological classification, and the Fundamental Plane
We present a photometric analysis of 65 galaxies in the rich cluster Abell
1689 at , using the Hubble Space Telescope Advanced Camera for Surveys
archive images in the rest-frame -band. We perform two-dimensional
multi-component photometric decomposition of each galaxy adopting different
models of the surface-brightness distribution. We present an accurate
morphological classification for each of the sample galaxies. For 50 early-type
galaxies, we fit both a de Vaucouleurs and S\'ersic law; S0s are modelled by
also including a disc component described by an exponential law. Bars of SB0s
are described by the profile of a Ferrers ellipsoid. For the 15 spirals, we
model a S\'ersic bulge, exponential disc, and, when required, a Ferrers bar
component. We derive the Fundamental Plane by fitting 40 early-type galaxies in
the sample, using different surface-brightness distributions. We find that the
tightest plane is that derived by S\'ersic bulges. We find that bulges of
spirals lie on the same relation. The Fundamental Plane is better defined by
the bulges alone rather than the entire galaxies. Comparison with local samples
shows both an offset and rotation in the Fundamental Plane of Abell 1689.Comment: 53 pages, 71 figures, MNRAS in pres
Tsallis and Kaniadakis statistics from a point of view of the holographic equipartition law
In this work, we have illustrated the difference between both Tsallis and
Kaniadakis entropies through cosmological models obtained from the formalism
proposed by Padmanabhan, which is called holographic equipartition law.
Similarly to the formalism proposed by Komatsu, we have obtained an extra
driving constant term in the Friedmann equation if we deform the Tsallis
entropy by Kaniadakis' formalism. We have considered initially Tsallis entropy
as the Black Hole (BH) area entropy. This constant term may lead the universe
to be in an accelerated mode. On the other hand, if we start with the
Kaniadakis entropy as the BH area entropy and then by modifying the Kappa
expression by Tsallis' formalism, the same constant, which shows that the
universe have an acceleration is obtained. In an opposite limit, no driving
inflation term of the early universe was derived from both deformations.Comment: 8 pages, preprint format. Final version to appear in Europhysics
Letter
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