98 research outputs found
Radiatively Induced Breaking of Conformal Symmetry in a Superpotential
Radiatively induced symmetry breaking is considered for a toy model with one
scalar and one fermion field unified in a superfield. It is shown that the
classical quartic self-interaction of the superfield possesses a quantum
infrared singularity. Application of the Coleman-Weinberg mechanism for
effective potential leads to the appearance of condensates and masses for both
scalar and fermion components. That induces a spontaneous breaking of the
initial classical symmetries: the supersymmetry and the conformal one. The
energy scales for the scalar and fermion condensates appear to be of the same
order, while the renormalization scale is many orders of magnitude higher. A
possibility to relate the considered toy model to conformal symmetry breaking
in the Standard Model is discussed.Comment: Improved final version with new references and misprints corrected, 9
pages , no figure
New spherically symmetric monopole and regular solutions in Einstein-Born-Infeld theories
In this work a new asymptotically flat solution of the coupled
Einstein-Born-Infeld equations for a static spherically symmetric space-time is
obtained. When the intrinsic mass is zero the resulting spacetime is regular
everywhere, in the sense given by B. Hoffmann and L. Infeld in 1937, and the
Einstein-Born-Infeld theory leads to the identification of the gravitational
with the electromagnetic mass. This means that the metric, the electromagnetic
field and their derivatives have not discontinuities in all the manifold. In
particular, there are not conical singularities at the origin, in contrast to
well known monopole solution studied by B. Hoffmann in 1935. The lack of
uniqueness of the action function in Non-Linear-Electrodynamics is discussed.Comment: Final version in journal. Amplied version with new results that
previous talk in Protvino worksho
The Newman-Janis Algorithm, Rotating Solutions and Einstein-Born-Infeld Black Holes
A new metric is obtained by applying a complex coordinate trans- formation to
the static metric of the self-gravitating Born-Infeld monopole. The behaviour
of the new metric is typical of a rotating charged source, but this source is
not a spherically symmetric Born-Infeld monopole with rotation. We show that
the structure of the energy-momentum tensor obtained with this new metric does
not correspond to the typical structure of the energy momentum tensor of
Einstein-Born-Infeld theory induced by a rotating spherically symmetric source.
This also show, that the complex coordinate transformations have the
interpretation given by Newman and Janis only in space-time solutions with
linear sources
Von Neumann's Quantization of General Relativity
Von Neumann's procedure is applied for quantization of General Relativity. We
quantize the initial data of dynamical variables at the Planck epoch, where the
Hubble parameter coincides with the Planck mass. These initial data are defined
via the Fock simplex in the tangent Minkowskian space-time and the Dirac
conformal interval. The Einstein cosmological principle is applied for the
average of the spatial metric determinant logarithm over the spatial volume of
the visible Universe. We derive the splitting of the general coordinate
transformations into the diffeomorphisms (as the object of the second N\"other
theorem) and the initial data transformations (as objects of the first N\"other
theorem). Following von Neumann, we suppose that the vacuum state is a quantum
ensemble. The vacuum state is degenerated with respect to quantum numbers of
non-vacuum states with the distribution function that yields the Casimir effect
in gravidynamics in analogy to the one in electrodynamics. The generation
functional of the perturbation theory in gravidynamics is given as a solution
of the quantum energy constraint. We discuss the region of applicability of
gravidynamics and its possible predictions for explanation of the modern
observational and experimental data.Comment: 14 pages, updated version with extended discussio
Emanation Study of Gas Radon on the Ancient Cuexcomate Geyser in Puebla City, Mexico
Radon measurements were collected over a period of nine months in the area of the ancient Cuexcomate geyser, in Puebla City. For measuring radon, the passive method of nuclear tracks in solids was used, using polycarbonate CR-39 as radiation sensitive material. Radon concentrations varied in strong anti-correlation with the rainfall intensity. And are lower compared to other locations, in concordance with the stratigraphic composition, as travertine and deposits of volcanic origin, corresponding to the geyser chemical composition and the active environment in the north part of the Trans-Mexican Volcanic Belt with an andesitic and basalt composition
Rotation and twist regular modes for trapped ghosts
A parameter-independent notion of stationary slow motion is formulated then
applied to the case of stationary rotation of massless trapped ghosts. The
excitations correspond to a rotation mode with angular momentum and
twist modes. It is found that the rotation mode, which has no parity, causes
excess in the angular velocity of dragged distant coordinate frames in one
sheet of the wormhole while in the other sheet the angular velocity of the
ghosts is that of rotating stars: . As to the twist modes, which all
have parity, they cause excess in the angular velocity of one of the throat's
poles with respect to the other.Comment: 11 pages, 3 figures; General Relativity and Gravitation - 201
Electrified BPS Giants: BPS configurations on Giant Gravitons with Static Electric Field
We consider D3-brane action in the maximally supersymmetric type IIB
plane-wave background. Upon fixing the light-cone gauge, we obtain the
light-cone Hamiltonian which is manifestly supersymmetric. The 1/2 BPS
solutions of this theory (solutions which preserve 16 supercharges) are either
of the form of spherical three branes, the giant gravitons, or zero size point
like branes. We then construct specific classes of 1/4 BPS solutions of this
theory in which static electric field on the brane is turned on. These
solutions are deformations about either of the two 1/2 BPS solutions. In
particular, we study in some detail 1/4 BPS configurations with electric dipole
on the three sphere giant, i.e. BIons on the giant gravitons, which we hence
call BIGGons. We also study BPS configurations corresponding to turning on a
background uniform constant electric field. As a result of this background
electric field the three sphere giant is deformed to squashed sphere, while the
zero size point like branes turn into circular or straight fundamental strings
in the plane-wave background, with their tension equal to the background
electric field.Comment: 32 pages, 1 eps figure; v2: Presentation of derivation of light-cone
Hamiltonian improved, Refs adde
Generalizations of Nonlinear and Supersymmetric Classical Electrodynamics
We first write down a very general description of nonlinear classical
electrodynamics, making use of generalized constitutive equations and
constitutive tensors. Our approach includes non-Lagrangian as well as
Lagrangian theories, allows for electromagnetic fields in the widest possible
variety of media (anisotropic, piroelectric, chiral and ferromagnetic), and
accommodates the incorporation of nonlocal effects. We formulate
electric-magnetic duality in terms of the constitutive tensors. We then propose
a supersymmetric version of the general constitutive equations, in a superfield
approach.Comment: 15 pages, based on the presentation by G. A. Goldin at QTS
Irreducible holonomy algebras of Riemannian supermanifolds
Possible irreducible holonomy algebras \g\subset\osp(p,q|2m) of Riemannian
supermanifolds under the assumption that \g is a direct sum of simple Lie
superalgebras of classical type and possibly of a one-dimensional center are
classified. This generalizes the classical result of Marcel Berger about the
classification of irreducible holonomy algebras of pseudo-Riemannian manifolds.Comment: 27 pages, the final versio
Seletividade e controle de grama-seda em aplicações sequenciais de herbicidas em cana-planta.
A grama-seda (Cynodon dactylon) infesta os canaviais, tem suas plantas perenizadas em curto espaço de tempo e consequentemente tornam-se tolerantes aos herbicidas. Para elucidar estratégias de controle objetivou-se avaliar aplicações sequenciais de herbicidas sobre a eficácia de controle da grama-seda e a seletividade sobre a cana-de-açúcar. O experimento de eficácia de controle foi conduzido em vasos de plástico (18 L) preenchidos com solo de textura arenosa e plantados com ramos de C. dactylon. As parcelas foram distribuídas em delineamento inteiramente casualizado e em sala de crescimento, regulada para atender as condições de verão do clima Cwa (Koppen). O experimento de seletividade foi conduzido em cana-planta com parcelas de 7,5 m x 25m e delineamento em blocos casualizados. Ambos os experimentos foram constituídos por 9 tratamentos em cinco repetições, sendo compostos pela aplicação de clomazone + sulfentrazone ou clomazone + indaziflam, cada um precedidos da ausência de herbicidas, imazapyr (aplicado 75 dias antes), clomazone ou indaziflam (aplicados 38 dias antes) e o tratamento testemunha. No experimento de eficácia avaliou-se a porcentagem de controle e a matéria seca das plantas aos 60 dias após a última aplicação e no experimento de seletividade a altura, estande, produtividade dos colmos e perfil isoenzimático da ?-esterase aos 315 dias após plantio da cultura. A aplicação de clomazone + sulfentrazone após 38 dias de pousio do clomazone diminuíram a matéria seca de Cynodon dactylon e não prejudicaram a altura, estande e produtividade dos colmos aos 315 dias após plantio
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