194 research outputs found
Electric-magnetic duality in linearized Ho\v{r}ava-Lifshitz gravity
Known as a symmetry of vacuum Maxwell equations, the electric-magnetic
duality can be lifted actually to a symmetry of an action. The Lagrangian of
this action is written in terms of two vector potentials, one electric and one
magnetic, and while it is manifestly invariant under duality rotations, it is
not manifestly Lorentz covariant. This duality symmetry exists also in
linearized gravity in four dimensions, and can be lifted off shell too. In
dimensions, the link between linearized gravity and its dual can also be seen
from the point of view of a parental action. This is defined by a first order
Lagrangian (with the help of some auxiliary variables) that delivers both
Fierz-Pauli theory and its dual. In this work we use this formalism to
implement the electric-magnetic duality in the nonrelativistic deviation of
Fierz-Pauli theory arising from Ho\v{r}ava-Lifshitz gravity. Because this
theory breaks diffeomorphism invariance, one finds that such implementation
includes some peculiarities.Comment: v1: 23 pages, 4 figures, edited with LaTeXila 2.4.0 and wxMaxima
12.04.0 for the graphics (Maxima version: 5.27.0). arXiv admin note: text
overlap with arXiv:1306.1092 by other authors; v2: 24 pages, 4 figures,
references added, negligence (leading to poor version management and
miscommunication) rectified; v3: typos and grammar corrected, minor changes
to uniformize convention
Consistent Non-Minimal Couplings of Massive Higher-Spin Particles
The mutual compatibility of the dynamical equations and constraints
describing a massive particle of arbitrary spin, though essential for
consistency, is generically lost in the presence of interactions. The
conventional Lagrangian approach avoids this difficulty, but fails to ensure
light-cone propagation and becomes very cumbersome. In this paper, we take an
alternative route--the involutive form of the equations and constraints--to
guarantee their algebraic consistency. This approach enormously simplifies the
search for consistent interactions, now seen as deformations of the involutive
system, by keeping manifest the causal propagation of the correct number of
degrees of freedom. We consider massive particles of arbitrary integer spin in
electromagnetic and gravitational backgrounds to find their possible
non-minimal local couplings. Apart from easily reproducing some well-known
results, we find restrictions on the backgrounds for consistent propagation of
such a particle in isolation. The results can be altered by non-local
interactions that may arise from additional massive states in the interacting
theory.Comment: 26 pages; to appear in Nuclear Physics B; analyses of consistent
backgrounds improve
Emergent Noncommutative gravity from a consistent deformation of gauge theory
Starting from a standard noncommutative gauge theory and using the
Seiberg-Witten map we propose a new version of a noncommutative gravity. We use
consistent deformation theory starting from a free gauge action and gauging a
killing symmetry of the background metric to construct a deformation of the
gauge theory that we can relate with gravity. The result of this consistent
deformation of the gauge theory is nonpolynomial in A_\mu. From here we can
construct a version of noncommutative gravity that is simpler than previous
attempts. Our proposal is consistent and is not plagued with the problems of
other approaches like twist symmetries or gauging other groups.Comment: 18 pages, references added, typos fixed, some concepts clarified.
Paragraph added below Eq. (77). Match published PRD version
La formación económico-social provincial : hacia una agenda de investigación del desarrollo desigual del capitalismo en Mendoza
Partiendo de un extenso recorrido en investigación y docencia ligadas a la realidad social mendocina, surgió en nuestro equipo la posibilidad de encarar una sistematización más amplia sobre la provincia: su estructura demográfica, productiva, económico- social, la identificación de regiones donde el desarrollo capitalista desigual ha plasmado diferencias notables, las condiciones de trabajo y la conflictividad social. Nos preguntamos: ¿Cuáles son los temas que se constituyen en núcleos problemáticos o ejes de investigación centrales para una comprensión global de la formación económico-social provincial, como totalidad social específica “compleja en el espacio y cambiante en el tiempo"? ¿Cuáles son las grandes contradicciones, tensiones y conflictos entre las principales clases, sectores, sujetos y actores sociales, que originan el movimiento de la sociedad mendocina? Tal tipo de estudio es necesario como diagnóstico de base para la elaboración de políticas públicas dirigidas al desarrollo social (no al mero crecimiento económico) y a la eliminación de las profundas desigualdades existentes.
En síntesis el proyecto se plantea la necesidad de comprender en clave sociológica, tanto el proceso histórico de los últimos treinta años, como resultado del mismo: la configuración actual de Mendoza. Partimos de los siguientes supuestos: a) Existen nudos problemáticos estructurales, que articulan y determinan el funcionamiento general de la sociedad mendocina; los que adecuadamente identificados, descubiertas sus múltiples relaciones, y expuestos organizadamente, permitirían una comprensión de la provincia como totalidad social. b) El desarrollo capitalista acelerado en los últimos 30 años ha invadido regiones geográficas y actividades económicas relativamente “atrasadas", imponiendo junto a la modernización productiva y las innovaciones tecnológicas, mayores niveles de concentración y extranjerización, en forma contradictoria con las condiciones materiales y subjetivas de amplios sectores explotados, expulsados, marginados, precarizados, etc. c) La totalidad social resultante de este proceso histórico muestra grandes disparidades regionales, heterogeneidad estructural y aguda polarización social.Fil: Cortese, Carmelo.
Universidad Nacional de Cuyo. Facultad de Ciencias Políticas y SocialesFil: Bauzá, Javier Ignacio.
Universidad Nacional de Cuyo. Facultad de Ciencias Políticas y Sociale
Dual actions for massless, partially-massless and massive gravitons in (A)dS
We provide a unified treatment of electric-magnetic duality, at the action
level and with manifest Lorentz invariance, for massive, massless as well as
partially-massless gravitons propagating in maximally symmetric spacetimes of
any dimension n>3. For massive and massless fields, we complete previous
analyses that use parent-action techniques by giving dual descriptions that
enable direct counting of physical degrees of freedom in the flat and massless
limit. The same treatment is extended to the partially-massless case, where the
duality has been previously discussed in covariant form only at the level of
the equations of motion. The nature of the dual graviton is therefore clarified
for all values of the mass and of the cosmological constant.Comment: 6 pages. A reference adde
A Variational Formulation of Symplectic Noncommutative Mechanics
The standard lore in noncommutative physics is the use of first order
variational description of a dynamical system to probe the space
noncommutativity and its consequences in the dynamics in phase space. As the
ultimate goal is to understand the inherent space noncommutativity we propose a
variational principle for noncommutative dynamical systems in configuration
space, based on results of our previous work [14]. We hope that this
variational formulation in configuration space can be of help to elucidate the
definition of some global and dynamical properties of classical and quantum
noncommutative space.Comment: 17 pages, Latex. Accepted for publication in IJGMM
Spin-2 twisted duality in (A)dS
Starting from the dual Lagrangians recently obtained for (partially) massless
spin-2 fields in the Stueckelberg formulation, we write the equations of motion
for (partially) massless gravitons in (A)dS in the form of twisted-duality
relations. In both cases, the latter admit a smooth flat limit. In the massless
case, this limit reproduces the gravitational twisted-duality relations
previously known for Minkowski spacetime. In the partially-massless case, our
twisted-duality relations preserve the number of degrees of freedom in the flat
limit, in the sense that they split into a decoupled pair of dualities for
spin-1 and spin-2 fields. Our results apply to spacetimes of any dimension
greater than three. In four dimensions, the twisted-duality relations for
partially massless fields that appeared in the literature are recovered by
gauging away the Stueckelberg field.Comment: 15 pages. Introductory remarks, clarifications and references adde
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