Posters (in alphabetical order):

1)Alexandre Leite Gadelha (IFT/UNESP, São Paulo, Brazil, with M. C. B. Abdalla and D. L. Nedel)

General Unitary TFD Formulation for Superstrings

Abstract: a generalization of the Thermo Field Dynamics (TFD) for fermionic degrees of freedom is proposed. Such generalization follows a previous one where the SU(1,1) thermal group was used to obtain the closed bosonic string at finite temperature. The SU(2) thermal group is introduced to construct a general thermal Bogoliubov transformation generator to get the fermionic sector of the superstring at finite temperature. The question about supersymmetry breaking is analyzed in the light of TFD approach.

2)Alexandre C. Tort (UFRJ, Rio de Janeiro, Brazil, with E. Elizalde,  D. P. Palma and F. C. Santos)

On the Casimir Energy of $\kappa$-Deformed Quantum Fields

The Casimir energy of $\kappa$-deformed scalar and electromagnetic fields under suitable boundary conditions is approached from the point of view of some complex analysis techniques that allow for the evaluation of non-trivial frequency spectra in a simple and effective way.

3)André Luiz Naves de Oliveira (UnB, Distrito Federal, Brazil)

Cosmological Implications of a Scalar-Tensor Chiral String

Abstract: in this work we derive the metric of a chiral cosmic string in the weak field approximation and study the mechanism of wake formation. With this, some cosmological implications are investigated. Work supported by FINATEC.

4)Antônio Edson Gonçalves (UEL, Paraná, Brazil, with Andrey Bytsenko and I. Alves Junior)

The Entropy/Energy Ratios for Scalar Fields on Noncommutative Flat Manifolds

Abstract: we consider  massless scalar fields in (S^1)X(R^3)X(M^2), where M^2 is a compact (noncompact) noncommutative space and calculate relevant thermodynamical functions and entropy/energy bounds in high temperature limits.


5)Clóvis Wotzacek (UFRJ, Rio de Janeiro, Brazil, with Patricio A. Gaete Duran)

Brane Condensation and Confinement

Abstract: we study the interplay between screening and confinement using the Julia-Toulousse mechanism in p-form electrodynamics coupled to eletric and magnetic branes that eventually condense. An example involving a Maxwell-Kalb-Ramond system in D=4 is presented.

6)Cristine Nunes Ferreira (UFRJ, Rio de Janeiro, Brazil, with José Abdalla Helayël Neto and Helder Chavez Sanchez)

A Discussion on Supersymmetric Potentials with Gauge-Field Mixing

Abstract: in this paper, following a stream of investigation on supersymmetric gauge theories with vortex solutions, we contemplate the possibility of building up a D-and-F term cosmic string by means of a gauge-field mixing in connection with a U(1)xU(1)` -symmetry. The spontaneous break of both gauge symmetry and supersymmetry are thoroughly analysed and the fermion zero-modes are worked out. The role of the gauge-field mixing parameter is elucidated in connection with the vortex configuration that comes out. We study a vortex solution of a N=1 supersymmetric extension of the Maxwell-Chern-Symons model. In this model the Lorentz symmetry is breaking. We also analyse the charged behaviour with U(1) supersymmetric model where we hope the the Chern Simons coupling to give us the possibility to obtain a charge inside of the vortex motivated by Lorentz breaking. As an application of the model presented here, we propose the possibility that the supersimetric cosmic string yield production of fermionic charge carriers that may eject, at their late stages, particles that subsequently decay to produce cosmic rays of ultra-high energy. In our work, it turns out that massive supersymmetric fermionic partners may be produced for a susy breaking scale in the range $10^{11}$ to 10^{13} GeV, which is compatible with the phenomenology of a gravitino mass at the TeV scale. We also determine the range of the gauge-field mixing parameter, \alpha , in connection with the mass scales of the present model. 

7)Daniel Luiz Nedel (IFT/UNESP, São Paulo, Brazil)

Superspace Type II 4D Supergravity from Type II Superstring

Abstract: we derive the torsion constraints and the of equations of motion of four-dimensional Type II supergravity in superspace. This is achieved by coupling the four-dimensional compactified Type II Berkovits' superstring to an N=2 curved background and requiring that the sigma-model has superconformal invariance at one loop. We compute this in a manifestly 4D N=2 supersymmetric way. The constraints break the target conformal and SU(2) invariances and the dilaton will be a conformal, $SU(2)\times U(1)$ compensator. For N=2 supergravity there are various possible types of compensators. However, worldsheet supersymmetry uniquely determines the correct type. For Type II superstring in four dimensions, worldsheet supersymmetry requires two different compensators. One type is described by chiral and anti-chiral superfields. This compensator can be identified with a vector multiplet. The other Type II compensator is described by twist-chiral and twist-anti-chiral superfields and can be identified with a tensor hypermultiplet. Also, the superconformal invariance selects a particular gauge, where the matter is fixed, but not the compensators.

8)Fabricio A. Barone (CBPF, Rio de Janeiro, Brazil, with J.A. Helayël Neto)

A Remark on the Aharonov-Bohm Potential and a Discussion on the Electric Charge Quantization 

Abstract: The purpose of this work is to stress on a mathematical requirement of the Stokes’ theorem that, naturally, yields a reassessment of the electric charge quantization condition, which is, here, explicitly carried out in the context of the Aharonov-Bohm set-up. We argue that, by virtue of an ambiguity in the definition of the circulation of the vector potential, a modified quantization condition comes out for the electric charge that opens the way for understanding fundamental fractional charges. One does not, any longer, need to rely on the existence of a magnetic monopole to justify electric charge quantization. 

9)Felipe Siqueira de Souza da Rosa (UFRJ, Rio de Janeiro, Brazil, with M. V. Cougo Pinto and C. Farina)

On the Casimir Effect for N-Dimensional Spheres

Abstract: in this work we compute the Casimir energy density for N-dimensional spheres using two distinct regularization prescriptions and show that some discrepancies may arise. It is shown that by introducing an exponencial cut-off one is driven into some expressions which are not very easy to handle with, in sharp contradiction with the well behaved results produced by the zeta function regularization. Regularization dependent results present a challenge for interpretations which are addressed in this work.

10)Jayme Felipe Martins Mendes (IME, Rio de Janeiro, Brazil, with M. V. Cougo-Pinto and C. Farina)

The Real and Imaginary Parts of Kappa-Deformed Effective Actions

Abstract: the effective action of a kappa-deformed scalar field has real and imaginary parts, being the former proportional to the half-sum of the field frequencies and the latter proportional to the sum of the squares of the frequencies. By imposing Dirichlet boundary conditions on the field the real part gives the Casimir energy while the imaginary part gives a creation rate of field excitations. A crossing of a cut in complex momentum plane gives rise to both Casimir energy and creation rate from the sole expression of the half sum of frequencies.


11)Moises Porfirio Rojas Leyva (CBPF, Rio de Janeiro, Brazil, with H. L. Carrion and F. Toppan)

Residual Symmetries in the Presence of an EM Background

Abstract: the symmetry algebra of a QFT in the presence of an external EM background (named ``residual symmetry") is investigated within a Lie-algebraic, model independent scheme. Some results previously encountered in the literature are here extended. In particular we compute the symmetry algebra for a constant EM background in D=3 and D=4 dimensions. In D= 3 dimensions the residual symmetry algebra, for generic values of the constant EM background, is isomorphic to $u(1)\oplus {\cal P}_c(2)$, with ${\cal P}_c(2)$ the centrally extended 2-dimensional Poincar\'e algebra. In D=4 dimension the generic residual symmetry algebra is given by a seven-dimensional solvable Lie algebra which is explicitly computed. Residual symmetry algebras are also computed for specific non-constant EM backgrounds and in the supersymmetric case for a constant EM background. The supersymmetry generators are given by the ``square roots" of the deformed translations.

12)Rafael Monteiro Fernandes (UNICAMP, São Paulo, Brazil, with Patricio S. Letelier)

Motion of a Classical Particle in a Soliton Field Configuration of the O(3) Non-Linear Model

Abstract: we analyse the motion of a particle whose internal space is the SU(2) symmetry group in the presence of a scalar field multiplete, namely, an unitary topological charge soliton of the Non-Linear O(3) Model. The equations of motion are derived from two expressions consistently proposed: a quadri-force referring to the external Minkowskian spacetime and an evolution equation describing the precession of the particle's isospin in the internal space. Analytical studies regarding stability and asymptotic behaviour of the dynamical system are presented and confirmed by numerical solutions of the equations of motion, revealing that all the equilibrium points are unstable and that there are no bounded orbits of such a system.

13)Regina Fonseca Ávila (IMECC-UNICAMP, São Paulo, Brazil, with Márcio José Menon)

Derivative Dispersion Relations

Abstract: we discuss some analytical and numerical aspects related with the replacement of Integral Dispersion Relations by Derivative Relations in the investigation of high-energy elastic hadron-hadron scattering. In particular we show that, in practice, once one subtraction constant is used as a free fit parameter the derivative approach is equivalent to the integral approach.

14)Renato M. Dória (FUNPAT, Rio de Janeiro, Brazil, with Flávia Agostini)

Electromagnetic Synapses

Abstract: electromagnetic synapses are derived from a Physics of Light based on an antireductionist gauge theory. A wholeness is built up in classical terms. New electromagnetic fields are calculated.

15)Thiago Gilberto do Prado (UEL, Paraná, Brazil, with Antonio Edson Gonçalves)

The BTZ Black Hole and the Cardy-Verlinde Formula

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. Bañados, Teitelboim and 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, 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 which is valid for spaces with an arbitrary number of dimensions. The main objective of the present work is the aplication of the Cardy-Verlinde formula from the study of the AdS/CFT correspondence, where AdS means anti-de Sitter space, and the field theory inside the BTZ black hole corresponds to the same quantities calculated in its boundary.

16)Vanderlei dos Santos Mendes (UEL, Paraná, Brazil, with Andrei A. Bytsenko and Alexandre C. Tort)

Thermodynamics of Abelian Gauge Fields in Real Hyperbolic Spaces

Abstract: we study gauge theories based on abelian p-forms on the compact real hyperbolic manifold. The spectral zeta function related to the laplacian, considering only the co-exact part of the p-forms, and corresponding to the physical degrees of freedom, can be represented by the inverse Mellin transform of the heat kernel, given in terms of the Freed formula. The explicit thermodynamic functions related to skew-symmetric tensor fields are obtained by using the zeta function regularization and the trace tensor kernel formula. Thermodynamic quantities in the high and low temperature expansions has been calculated and new entropy/energy ratios established.

17)Wander Gomes Ney (CBPF, Rio de Janeiro, Brazil, with Wesley Spalenza and José Abdalla Helayël Neto)

N=2 SUSY Formulation of Lorentz- and CPT-Breaking Gauge Theories

Abstract: the formulation of physical models for fundamental particles in the framework of quantum field theories is based on Lorentz and gauge symmetries. However, mechanisms of breaking of these symmetries have been proposed and discussed in view of some phenomenological and experimental evidences. Astrophysical observations indicate that Lorentz symmetry may be slightly violated in order to account for anisotropies. Then, one may consider a gauge theory where Lorentz symmetry breaking may be realized by means of a term in the action. A Chern-Simmons-type term may be considered that exhibits a constant background four-vector that maintains the gauge invariance but breaks down the Lorentz space-time symmetry. In the context of supersymmetry and, more particularly, considering the importance of extended supersymmetries in connection with gauge theories, we propose in this work an N=2 extended supersymmetric generalization of the Lorentz-breaking Chern-Simoms term in a 4-dimensional Minkowski background. We start with the Chern-Simons term in (1+5) space-time and adopt the dimensional reduction method to obtain the bosonic sector of the N=2,D=4 supersymmetry. This is possible because in D=6,N=1-supersymmetry the bosonic sector has the same number of degree of freedom as the bosonic sector of an $N=2-D=4$ SUSY model. Then, we obtain that bosonic sector for N=2 Lorentz broken Lagrangian has two complex scalar and a complex rank-2 anti-symmetric tensor field as background fields. Once the bosonic sector is identified, we adopt an N=1-superfield formalism to write down the gauge and the background supermultiplets and then we set up their coupling in terms of an N=2 action realised in N=1-superspace. The result is projected out in component fields and we discuss the role of the background partners for the central charge of the N=2 Lorentz broken action.