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Posters (from Monday, 04/24, to Friday, 04/28):
Alberto Saa (IMECC - UNICAMP, Brazil), in collaboration with
Luciana A. Elias
Non-Minimally
Coupled Cosmology as Geodesic Motion
Abstract:
Townsend and co-workers have recently shown that the equations of motion of
homogeneous and isotropic cosmologies involving $N$ minimally coupled
scalar fields, with arbitrary potential, are equivalent to the geodesic
equations of an extended space. For homogeneous and isotropic cosmologies
with flat spatial sections ($\kappa=0$), the extend space is
($N+1$)-dimensional and has $(1,N)$ signature, while for non-flat
($\kappa=\pm 1$) cosmologies, the extend space is ($N+2$)-dimensional and
has signature ($1,N+1$) for $\kappa=-1$ and ($2,N$) for $\kappa=1$. For all
the cases, the
geodesic are timelike if $V>0$, null if $V=0$
and spacelike if $V<0$. This analysis is
generalized here to include also non-minimally coupled scalar fields. These
results can be useful to classify the asymptotic behavior of homogeneous
and isotropic cosmological models, leading, for instance, to some
geometrical criteria for the existence of accelerated expansion phases.
Alexandre Carlos Tort (Instituto de Física, Universidade
Federal do Rio de Janeiro, Brazil),
in collaboration with
F. C. Santos (UFRJ) and E. Elizalde (IEEC/UB/UAB)
Analytical Regularisation and Confined Quantum Fields
Abstract: A
technique for evaluating the regularised vacuum
energy stemming from non-trivial boundary conditions is reviewed and
results for the Casimir energy of a massive fermionic field confined by a $d+1$ dimensional
slab-bag and the effect of a uniform magnetic field on the vacuum energy of
a confined massive bosonic and fermionic fields are presented. Results concerning the Casimir energy and the evaluation of the rate of quanta
creation in $\kappa$-deformed theories are also discussed.
Álvaro Gomes dos Santos Neto (Instituto de Física, Universidade de
Brasília, Brazil), in collaboration
with A. G. Santos Neto and
M. E. X. Guimaraes (UnB)
Type-Like
Vortices Solutions in Scalar-Tensor Gravities
Abstract: We analyze a vortex line model in the contexte of a class of scalar-tensor theories of
gravity. We obtain exact solutions for the gravitational field of the
vortex in the particular case of Brans-Dicke
theory.
Andre Luiz Naves de Oliveira (Instituto de Física, Universidade de
Brasília, Brazil), in collaboration
with M. Leineker Costa and M.E.X. Guimaraes (UnB)
On the
Contributions from Dilatonic Strings to the Flat Behaviour of the Rotational Curves in Galaxies
Abstract: We analyse the
flat behaviour of the rotational curves in same
galaxies in the framework of a dilatonic,
current-carrying string. We determine the expression of the tangential
velocity of test objects following a stable circular equatorial orbit in
this spacetime.
Celso Melchiades
Doria (Universidade Federal de Santa Catarina, Brazil)
Morse
Theory Framework for the Seiberg-Witten Equations
Abstract: It is shown that the Seiberg-Witten
equations are obtained from a variational
formulation and that the functional satisfies the Palais-Smale
condition. Consequently, the equations admit a solution for all spin^{c}
structure. However, the solution may not be a Seiberg-Witten
monopole but just a cohomology class in H^{1}(X,R).
Chrystian de Assis Siqueira (Instituto de Física, Universidade de
Brasília, Brazil),
in collaboration with A. E. Santana (UnB)
Thermofield
Dynamics and Path-Integral Formalism
Abstract: Thermofield
dynamics (TFD), a real-time formalism for thermal quantum field theory, is
formulated in terms of a path-integral approach following the Weinberg
procedure. In order to assure precise rules for the development, we use a
representation for Lie-algebras such that the TFD algebraic ingredients are
derived, including the tilde conjugation rules. The association with the
canonical formalism is obtained, and for the case of bosons, we introduce
the Feynman diagrams and derive the n-point functions.
Cresus Godinho (LAFEX-CBPF, Brazil),
in collaboration with
Martim Lourenço (Pontifícia Universidade Católica - RJ)
Constraints
on the Non-commutative Quantum Hall Effect
Abstract: We analyse the
Classical and Quantum Hall Effect, based on the Noncommutative
Schrödinger - Chern-Simons Action. The
constraints are obtained by means of the Fadeev-Jackiw
quantization Scheme and guide us to an interesting new corrected Hall
conductivity expression.
Cristine Nunes Ferreira (CEFET-Campos, Brazil), in collaboration with
José A. Helayël-Neto (LAFEX-CBPF)
Supersymmetric
Superfluid in a Lorentz-Violating Background
Abstract: This work presents a supersymmetric
scenario for a global vortex with the superfluid behaviour. In our formulation, the duality relation
between the vortex configuration and a 2-form gauge field is the
key-element. The Lorentz-breaking background is also suitably accomodated in a superfield
and the duality between the vortex and the Kalb-Ramond
field is duely formulated in the N=1-superspace.
We then find that the embedding of the superfluid
vortices in a supersymmetry model dictate the
introduction of terms that softly break supersymmetry
in an explicit way and an interpretation of the parameters that govern
these SUSY breaking terms is found out in terms of the energy scales for
the vortex formation.
Daniel Heber Theodoro Franco (Centro de Estudos de Física Teórica, Brazil), in collaboration with Luiz H. Renoldi
Paley-Wiener-Schwartz
Theorem and Microlocal Analysis of Singularities
in Theory of Tempered Ultrahyperfunctions
Abstract: We study the Fourier-Laplace transform of
tempered ultrahyperfunctions introduced by Sebastião e Silva and Hasumi.
We establish a generalization of Paley-Wiener-Schwartz theorem for this
setting. This theorem is interesting in connection with the microlocal analysis of singularities of tempered ultrahyperfunctions.
Davi Cabral Rodrigues (Instituto de Física, Universidade
Federal do Rio de Janeiro, Brazil),
in collaboration with
Clóvis Wotzasek (
IF-UFRJ , Brazil
)
Issues on
3D Noncommutative Electromagnetic Duality
Abstract: We extend the ordinary 3D electromagnetic
duality to the noncommutative (NC) space-time
through a Seiberg-Witten map to second order in
the noncommutativity parameter $\theta$, defining
a new scalar field model. There are similarities with the 4D NC duality,
these are exploited to clarify properties of both cases. Up to second order
in $\theta$, we find duality interchanges the 2-form $\theta$ with its
1-form Hodge dual ${^\star} \theta $ times the gauge coupling constant,
i.e., $ \theta\rightarrow {^\star} \theta \; g^2$
(similar to the 4D NC electromagnetic duality). We prove that this property
is false in the third order expansion in both 3D and 4D space-times. Starting
from the third order expansion, $\theta$ cannot be rescaled to attain an
S-duality; on the other hand, to any order in $\theta$, it is possible to
rescale the fields to obtain the same coupling constants in both dual
descriptions. In addition to possible applications on effective models, the
3D space-time is useful for studying general properties of NC theories. In
particular we show that many terms of the Seiberg-Witten
mapped action in this dimension can be significantly simplified.
Fábio Macêdo
Mendes (Instituto de
Física, Universidade de Brasília, Brazil), in collaboration with Anníbal Dias Figueiredo Neto (UnB)
Generalized
Entropies in the Statistical Foundations of Thermodynamics
Abstract: We offer an alternative account for the
so called generalized entropies which follows naturally from the ubiquitous
Boltzmann's formula "S = k ln W".
Non-exponential laws would appear naturally in a unified framework where
generalized entropies might follow either from ab
initio counting procedures or as effective entropies that fits some unknown
parameters of a physical process. We consider the implication of
non-standard entropic forms to thermodynamics. Additionally, the relation
between our formalism and Jaynes/Gibbs (MAXENT)
inference procedure is explored. A generalization of the usual Darwin
Fowler method to account non-standard entropic forms is thus employed.
Fábio Pascoal dos Reis (Instituto de Física, Universidade
Federal do Rio de Janeiro, Brazil), in collaboration with C. Farina
(IF-UFRJ, Brazil)
On the
Particle Creation in a Robertson-Walker Universe
Abstract: It's well know
that nonstatic curved space-time can lead to the
phenomenon of particle creation. The fist one to discuss this kind of
problem was Schr\"odinger in 1939 [1]. In a
recent work [2], the problem of particle creation in $3+1$ a spatially
closed Robertson-Walker space-time is investigated. However we have found a
little mistake in the total number of particles produced and in the total
energy calculated by the author. In our work, we correct this mistake and
also, analyze graphically how the parameters of the metric affect the total
number of particles produced. $[1]$ E. Schr\"odinger, Physica (
Utrecht
), {\bf 6}, 899, (1939). $[2]$ M.R. Setare, Int.J.Theor.Phys.
{\bf 43} 2237 (2004).
Fabricio
Augusto Barone Rangel (DFQ-UNESP, Guaratinguetá,
Brazil)
Casimir
Energy for Point-like Objects
Abstract: In this paper it is presented the
calculus of the Casimir energy for point-like
objects. Specifically, it is studied the Casimir
energy of the scalar field interacting with two delta potentials localized
at two distinct points. The limit of strong coupling between the field and
the potentials is equivalent to the situation where the field satisfies Dirichlet boundary condition on the points where the
potentials are localized. For this case, the Casimir
energy is inversely proportional to the distance between the points.
Franciscus Jozef Vanhecke (Instituto de Física, Universidade Federal do Rio de Janeiro,
Brazil), in collaboration
with A. R. da Silva and
C. Sigaud
Symmetries
in Non Commutative Configuration Space
Abstract:
A group $G$ acting on a symplectic manifold $M$
is a Symmetry Group if there is a group homomorphism :
\[\phi :G \rightarrow {\cal S}p(M)\] where ${\cal
S}p(M)$ is the group of diffeomorphisms
conserving the symplectic two-form $\omega$ of M.
The vector fields, generators of these transformations are {\it locally
Hamiltonian} i.e. there is a Lie algebra homomorphism from the Lie algebra
${\cal G}$ to the locally Hamiltonian vector fields $Ham_0(M)$:
\[\phi_*:{\cal G}\rightarrow Ham_0(M):{\bf u}\rightarrow{\bf X}({\bf u})\;;\; \;d(\imath_{{\bf X}({\bf u})}\,\omega)=0\] The action is
called almost Hamiltonian if each generator ${\bf X}({\bf u})$ is
Hamiltonian ($\in Ham(M)$). This means that, for each ${\bf u}\in{\cal G}$,
there exists a linear map ${\bf f}:{\cal G}\rightarrow
{\cal F}(M):{\bf u}\rightarrow f({\bf u})$ on $M$
such that $d f({\bf u})=\imath_{{\bf X}({\bf
u})}\,\omega $.\\ Let ${\cal F}(M)$ denote the Lie algebra of functions on
$M$ endowed with the Lie algebra of the Poisson structure associated to
$\omega$.\\ There is an horizontal exact sequence of Lie algebra homomorphisms \begin{eqnarray*}&&\{0\}\rightarrow{\bf R}\rightarrow{\cal
F}(M)\rightarrow Ham(M)\rightarrow\{0\}\\
&& \phantom{\{0\}\rightarrow{\bf R}\rightarrow{\cal F}(M)}\nwarrow{\bf
f}\,\quad\uparrow \phi_*\\ &&
\phantom{\{0\}\rightarrow{\bf R}\rightarrow{\cal F}(M)\rightarrow}\quad\quad{\cal
G} \end{eqnarray*} When ${\bf f}$ is also a Lie
algebra homomorphism, the action is said to be {\it strictly Hamiltonan} and allows a momentum map.\\ The group
action on configuration space $Q$ induces an action on a cotangent bundle
$T*(Q)$, which is strictly Hamiltonian on $T^*(Q)$ with its canonical symplectic structure $\omega_0=dq^i\wedge
dp_i$.\\ In this note, we examine what happens
when $T*(Q)$ is endowed with a more general symplectic
structure: \[\omega=\omega_0+1/2\,F_{ij}\,dq^i\wedge dq^j+1/2\,G^{kl}\,dp_k\wedge dp_l\] with
$d\omega=0$, which generates a non commutative configuration space.
Gabriel Santos Menezes (ICRA-CBPF,
Brazil),
in collaboration with N. F. Svaiter (ICRA-CBPF, Brazil)
Stochastic
Quantization of Topological Field Theory: Generalized Langevin
Equation with Memory Kernel
Abstract: We use the method of stochastic
quantization in a topological field theory defined in an
Euclidean space, assuming a Langevin equation
with a memory kernel. We show that our procedure for the Abelian Chern-Simons theory
converges regardless of the nature of the Chern-Simons
coefficient.
Humberto Belich
Júnior (Universidade
Federal do Espírito Santo, Brazil), in collaboration with T.
Costa-Soares, M.M. Ferreira Jr., M.T.D. Orlando
Bose-Einstein
Condensates in a Lorentz Breaking Background
Abstract: This type of Lorentz and CPT symmetries
breaking has appeared in the context of high energy physics. The well known
Anderson-Higgs mechanism is generalized to a context of string theory in
such way that we obtain a four vector background field. Recently, the
proposal of the reminiscent effects of Lorentz and CPT breaking in non-relativistic
quantum mechanics was investigated with the non-minimal coupling recipe.
Such coupling presents a new type of phase generation and we can
investigate the influences of this background in a variety of phase
transitions. In the present work, we shall propose to reasses
the Bose-Einstein Condensates (BEC) going from a Relativistic theory with
this non-minimal coupling to a Lorentz and CPT breaking background to
computing its non-relativistic limit and study the contribution of the
background in the Gross-Pitevskii equation for
the BEC. The non-minimal coupling was chosen to be the one that generates
an Aharonov-Casher phase, in the sense that we
would like to study circular states in this system.
Jean Paulo Spinelly
da Silva (Universidade Estadual da Paraíba, Brazil),
in collaboration with
E. R. Bezerra de Mello
Vacuum
Polarization in the Presence of Magnetic Flux at Finite Temperature in the
Cosmic String Background
Abstract: In
this paper we analyse the vacuum polarization
effect associated with the charged massless
scalar field, in the presence of magnetic flux at finite temperature, in
the cosmic string background. We consider a spacetime
of an idealized cosmic string which presents a magnetic field confined in a
cylindrical tube of finite radius. Two situations are taken into account in
our analysis: (i) a homogeneous field inside the
tube and (ii) a magnetic field proportional to $1/r$. In these two cases,
the axis of the infinitely long tube of radius $R$ coincides with the
cosmic string. Specifically, we calculate the effects produced by the
temperature in the renormalized vacuum expectation value of the square of
the charged massless scalar field, $\langle\hat{\phi}^{\ast}(x)\hat{\phi}(x)\rangle$.
Therefore, in order to realize these analysis, we
calculate the Euclidean Green function associated with this field in this
background.
Josefa Surek
de Souza de Oliveira
(Departamento de Física, Universidade Estadual de Londrina, Brazil), in collaboration with Veríssimo Manoel de Aquino
Approximate
Solution of the Evolution Operator of the Neutrino System
Abstract: Neutrino flavor osccilations
have been supposed as an explanation for neutrino discrepancies in varied
contexts. One of them is the atmospheric neutrino problem. As a consequence
of the spherical geometry of the neutrino source volume it’s
predicted that atmospheric neutrino flux is up-down symmetric. If this
symmetry is not observed then a possible explanation is neutrino
oscillation. In this work the evolution operator of the neutrino system at
variable eletron density is computed as the
product of infinitesimal operators in the context of existence of two
neutrino flavors with extension for three flavors. The relations between
survival probability and energy and mixing angles at vacuum are analysed. The up and down fluxs
are calculated considering neutrino oscillation to energy 5 GeV for down neutrinos that cross the upper mantle.
Julio Marny Hoff da Silva (Instituto de Física Teórica-UNESP, Brazil), in collaboration with
M.C.B. Abdalla and M.E.X. Guimarães
Vortices
Solutions in Chern-Simons-Maxwell-Higgs System.
Abstract: In this work we analyse
some characteristcs of Bogomol'nyis
equations for abelian gauge theories with Chern-Simons-Maxwell-Higgs terms. We don't obtain the
complete solution for the model, but we analyse
the equations in a kind of weak field approximation instead of using a
computational analysis. Our main idea is to get some intuition on the
subject. Working with the equations in such approach we reproduce the
accurate behavior next to the origin.
Leonardo Paulo Guimarães de Assis
(LAFEX-CBPF, Brazil), in collaboration with J. A. Helayël-Neto
(LAFEX/CBPF, Rio de Janeiro & GFT-JLL, Petrópolis)
and F. Haas (UNISINOS, Sao Leopoldo) and Álvaro Luis Martins de Almeida Nogueira
(DEPBG/DEPES/CEFET/RJ and GFT-JLL, Petrópolis)
On the Stabiliser Rôle of the
Critical Coupling of an N=2 Maxwell-Chern-Simons-Higgs
Mechanical Model
Abstract: We apply different integrability
analysis procedures to a reduced (spatially homogeneous) mechanical system
derived from an off-shell non-minimally coupled N=2 Maxwell-Chern-Simons-Higgs model that presents BPS topological
vortex excitations, numerically obtained with an ansatz
adopted in a special - critical coupling - parametric regime. As a counterpart
of the regularity associated to the static soliton-like
solution, we investigate the possibility of chaotic dynamics in the
evolution of the spatially homogeneous reduced system, descendant from the
full N=2 model under consideration. The originally rich content of
symmetries and interactions, N=2 susy and
non-minimal coupling, singles out the proposed model as an interesting
framework for the investigation of the role played by (super-)symmetries
and parametric domains in the triggering/control of chaotic behavior in
gauge systems. After writing down effective Lagrangian
and Hamiltonian functions, and establishing the corresponding canonical Hamilton
equations, we apply global integrability
Noether point symmetries and Painleveproperty
criteria to both the general and the critical coupling regimes. As a non-integrable character is detected by the pair of
analytical criteria applied, we perform suitable numerical simulations, as
we seek for chaotic patterns in the system evolution. Finally, we present
some Comments on the results and perspectives for further investigations
and forthcoming communications.
Marcelo Botta Cantcheff (Instituto de Física Teórica-UNESP, Brazil)
Lorentz Symetry Breaking in Gravity and Dimensional Reduction.
Abstract: This is a work in progress where we
propose a modification of the standard Einstein Theory in four dimensions.
A new topological term is introduced in the sector of coupling with matter
and a Lorentz symmetry breakingis induced through
a mechanism proposed in a recent paper (hep-th/0411254). An effective
"planarity" may be observed in the resulting theory which
resembles some aspects of holography.
Marcelo Leineker
Costa (Instituto de
Física, Universidade de Brasília, Brazil), in collaboration with A. L.
Naves de Oliveira e M. E. X. Guimaraes
On the
Generalized Rainich Algebra in Scalar-Tensor
Gravities
Abstract: We obtain exact solutions for a static
and charged cosmic string in a Einstein-Maxwell-Dilaton theory of a scalar-tensor type in
(3+1)-Dimensions. This theory is specified by the dilaton
field $\phi$, the graviton field $g_{\mu\nu}$ and the electromagnetic field $F_{\mu\nu}$, and one post-Newtonian parameter
$\alpha(\phi)$. It contains three different cases, each of them
corresponding to a particular solution of the Rainich
algebra for the Ricci tensor.
Rafael de Lima Rodrigues (Universidade
Federal de Campina Grande, Brazil),
in collaboration with A. F. de Lima, E. R. Bezerra
de Mello and V. B. Bezerra
SUSY QM
from Three Domain Walls in a Scalar Potential
Abstract: The soliton
solutions have been investigated for field equations defined in a
space-time of dimension equal or bigger than 1+1. The kink solution of a
field theory is an example of a soliton in 1+1
dimensions. From field theoretic superpotential
evaluated on the domain states the algebraic framework of supersymmetry in quantum mechanics (SUSY QM), as
formulated by Witten
may be elaborated. The SUSY QM generalization of the harmonic
oscillator raising and lowering operators has several applications. The
generalization of SUSY QM for the case of matrix superpotential, is well
known in the literature for a long time, for one-dimension systems about on
non-relativistic quantum systems. In this work we construct a matrix general
superpotential on a three-field potential model
in 1+1 dimentions. The classical configurations
with domain wall solutions are bidimensional
structures in 3+1 dimensions. They are static, non-singular, classically
stable Bogomol'nyi \cite{Bogo}
and Prasad-Sommerfield \cite{PS} (BPS) soliton (defect) configurations, with finite localized
energy associated with a real scalar field potential model. Domain walls
have several applications in condensed matter and cosmology. The BPS states
are classical configurations that satisfy the first order differential
equations and the second order differential equations (equations of
motion). Domain walls have been recently exploited in a context that
stresses their connection with BPS-bound states. While Rajaraman
has applied the trial orbit method for the equation of motion, here one
uses the trial orbit method for the first order differential equations
associated to three real scalar fields. However, for solitons
of three coupled scalar fields there are no general rules for finding
analytic solutions since the nonlinearity in potential leads to enlarging
of difficulties to solve the BPS equations and field equations.
Rafael A. Vera
(Universidad de Concepcion,
Chile)
A Short-Cut
to Non-Local Relativity, a General Theory Based on Dual Properties of Light
Abstract: This theory is based on another form of
the equivalence principle found from fundamental experiments according to
which uncharged particles and radiation in stationary state obey the same
inertial and gravitational laws [1]. Effectively, the theoretical
properties of a particle model (PM) made up of radiation in stationary
state, derived from just dual properties of light, correspond with all of them:
the Einstein’s equivalence principle (EEP),
special relativity, quantum mechanics, all of the traditional G tests, and
recent astronomical observations [1][2][3]. Therefore this theory can be
used to test the current hypotheses in physics. In the short cut done here
it is proved that gravitation is an optical phenomenon produced by a
gradient of the relative refraction index of the space with respect to any
observer at rest in the field. During the free propagation of a body, to
the contrary of current physics, its “relative” frequencies and mass-energy
with respect to any observer at rest in the field are conserved. When the
body stops in the field, the change of its relative mass-energy is just
equal to the energy released. Thus, the G energy comes not from the G field
but from a fraction of the mass-energy of the body. This result is in
opposition with: a) the Einstein’s G field energy
hypothesis (GFEH) in that the G field gives up the energy for the G work
and b) the classical hypothesis in that the relative rest-mass of a body
with respect to the observer is independent on the difference of G
potential between them. Thus the right predictions of GR for the
conventional G tests would come from cancellations of errors of the same
absolute value and opposite signs of wrong hypotheses. Such errors stand
out in more critical tests that are independent of such hypotheses. The
relative changes occurring after changes of velocity, G potential and
universe expansion, cannot be found from local measurements because
everything changes in a common proportion and, therefore, every local ratio
remains unchanged. The lack of energy of the G field is most important in
universe evolution because the new kind of “linear” black hole without
singularity, after a long period of radiation absorption, decays into
primeval gas that can regenerate dead galaxies in relatively short periods.
Thus galaxies should evolve in rather closed cycles with luminous and dark
periods so that, in the average, the entropy in the universe can remain
constant, indefinitely. This is consistent with all of them: the rather
uniform distribution of elliptical galaxies, near us and in the deep field
universe, the increasing proportion of dark matter in galaxies of smaller
luminous sizes, the high proportion of dark matter between them, and the
low temperature CMB[4]. References [1]. R. A.
Vera. Proceedings of the Einstein Centennial Symposium on Fundamental
Physics. eds. S. M.
Moore et al, Universidad de Los Andes
. Bogotá, G. Violíni, Universitá di Roma, p. 597-625 (1981).
http://www2.udec.cl/~rvera [2]. R. A. Vera. International
Journal of Theoretical Physics. 20 p. 19-50 (1981) [3]. R. A. Vera. “The
New Universe Fixed by the Equivalence Principle and Properties of Light:” (ed. R. Vera. Universidad de
Concepción. Concepción. Chile. (1997). [4]. R. A. Vera. The
Dark Matter and Radiation Backgrounds Predicted from a New Principle and a
New Gravitational Theory. in Progress in Dark
Matter Research Ed. Blain, J. Val.( Nova Science Publishers,
2005), p 241-252.
Renato Doria
(AprendaNet, Brazil)
Ubiquous Lux
Abstract: Based on an Antireductionist Gauge Theory
applied to U(l) group one develops new properties
for light. They are a new dispersion relation yielding a group velocity
bigger than c, self interacting photons, non-linear wave equations, photon
quanta composed by fields. These new light properties are derived from an
extension to Maxwell equations. This means that Maxwell is preserved as Newton
to Einstein mechanics. This physics of light goes beyond the
principle that light is derived from electric charges. It says that light anteceeds electric charge. Being the only one absolute
that physics detects in Nature, light should be considered something
special. Besides turning the others physical entities as relative, it
should also to become ubiquous. Thus one
interprets that light should interact simultaneously with a set of fields.
In terms of gauge theory be a genuine gauge field
while others are potential fields. New aspects are derived from this
physics of light. Maxwell equations are extended and a new expression for
force just depending on fields is obtained.
Ricardo M. Bentin
(Universidade Estadual de Santa Cruz, Brazil)
An Attempt
of Construction for the Grassmann Numbers.
Abstract: We will pursue a way of building up an
algebraic structure that involves, in a mathematical abstract way, the well
known Grassmann variables. The problem arises
when we tried to understand the grassmannian
polynomial expansion on the scope of ring theory. The formalization of this
kind of variables and its properties will help us to have a better idea of
some algebraic structures and the way they are implemented in models
concerning theoretical physics .
Roldão da Rocha (Instituto de Física, UNICAMP, Brazil), in collaboration with Carlos H. Coimbra-Araújo
Physical
Effects of Extra Dimension and Concomitant Map between Photons and
Gravitons in RS Brane-World Scenario
Abstract: We show how the existence of an extra
dimension in Randall-Sundrum brane-world
model can estimate the correction in the horizon of Schwarzschild, Reissner-Nordström and Kerr black holes, and
consequently the measurability of physical effects due to extra dimensions
endowing the geometry of a brane-world scenario
in an AdS5 bulk. We also investigate the mutual transformation of photons
and gravitons in the field of a charged black hole in a brane-world
Randall-Sundrum scenario. Also, we show the
number of gravitons and photons are not conserved on the brane due to a source term coming from Mawell-Einstein field equations on the brane. It can be explained in terms of the leaking of
gravitons out of the brane into the AdS bulk
Sergio de
Oliveira Vellozo (Centro Tecnológico do Exército (CTEx) and LAFEX-CBPF, Brazil), in collaboration with
José Abdala Helayël Neto, Alexander William Smith and Leonardo Paulo Guimarães de Assis
Born-Infeld Magnetostatic Field
from Electrical Point-like Charge at Rest in an Inertial Frame
Abstract:
Born-Infeld non-linear Abelian
classical electrodynamics has a non-polynomial Lagrangian
with no derivative and interative terms.
Therefore the canonical equations have the same features. In this work we
employed this non-linear Lagrangian to
investigate the static electric and magnetic fields generated by a
point-like charge at rest in an inertial frame. Associated with usual
Maxwell differential equations we arrived on an
system of equations and the solution are real and non singular. Speculative remarks on a semiclassical model are proposed.
Thiago Gilberto do Prado (Universidade Estadual de Londrina, Brazil), in collaboration with A. E. Gonçalves
The Aplication of the Cardy-Verlinde
Formula in BTZ Black Hole
Abstract: The fascinating properties of the
classical, and especially quantum, black holes,
have long made it desirable to have avaliable a
lower dimensional analog which could exhibit the key features without the
usual complications. M. Bañados, C. Teitelboim and J. Zanelli
have proposed a interesting lower dimensional
black hole with a negative cosmological constant, known as BTZ black hole.
Starting from the holografic principle in the
context of closed $(n+1)$-dimensional Friedman-Robertson-Walker universe in
the radiation dominated era, E. Verlinde had
proposed an interesting formula that expresses the entropy of a Conformal
Field Theory (CFT) in terms of the Casimir energy
via a universal Cardy formula that is valid for
space with an arbitrary number of dimensions. The main objective of the
present work is the aplication of the Cardy-Verlinde formula in order to study the AdS/CFT correspondence, where AdS,for BTZ black holes.
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