String Theory
Mostrando 1-12 de 32 artigos, teses e dissertações.
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1. Estudo das frequências quasinormais das p-branas negras / Study of quasinormal frequency of black p-branas
Esta tese visa realizar um estudo acerca das freqüências quasinormais das p-branas negras utilizando um campo escalar de teste. No contexto da correspondência AdS/CFT estudamos alguns aspectos da formação de estados supercondutores na teoria de campos definida na borda do espaço-tempo de Gauss-Bonnet AdS d-dimensional. Apresentamos a derivação das so
Publicado em: 2010
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2. Low-energy parabosonic membrane: new critical dimensions and deformed noncommutativity
We study a classical perturbative membrane based on the string-limit model and we discuss the consistency of the theory where the closure of the classical constraints algebra is verified. We paraquantize the model (extended string) both in the covariant and the transverse approaches. From the generalized Poincaré algebra, the so-called Poincaré (para) alge
Brazilian Journal of Physics. Publicado em: 2009-12
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3. Cordas em espaços deformados / Strings in deformed space
In this thesis we studied rotating and oscillating strings under the AdS/CFT correspondence. These strings move in the AdS5 × S5, Lunin and Maldacena, R1, 9 and deformed R1, 9 spaces. In the case of the rotating string, the giant magnon and the spiky string were determined. In the case of the oscillating string, we found the solutions fo the classical equat
Publicado em: 2009
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4. O chiste em Tutaméia: riso que (des)vela
The aim of this paper is to present the study of the laughter in Tutaméia, by João Guimarães Rosa, throughtout the four forewords and ten novels selected from the authors literary work. It is based on the psychoanalytical theory of Sigmund Freud and Jacques Lacan about the laughter (and delight in the humorous nuances) and the unconscious mind. By taking
Publicado em: 2009
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5. Linear pertubations of black roles: stability, quasi-normal modes and tails / Perturbações lineares de buracos negros: estabilidade, modos quase-normais e caudas
Black holes have their proper oscillations, which are called the quasi-normal modes. The proper oscillations of astrophysical black holes can be observed in the nearest future with the help of gravitational wave detectors. Quasi-normal modes are also very important in the context of testing of the stability of black objects, the anti-de Sitter/ Conformal Fie
Publicado em: 2009
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6. Integrable inhomogeneous spin chains in generalized Lunin-Maldacena backgrounds
We obtain through a Matrix Product Ansatz the exact solution of the most general inhomogeneous spin chain with nearest neighbor interaction and with U(1)² and U(1)³ symmetries. These models are related to the one loop mixing matrix of the Leigh-Strassler deformed N = 4 SYM theory, dual to type IIB string theory in the generalized Lunin-Maldacena background
Brazilian Journal of Physics. Publicado em: 2008-09
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7. The Matrix Product Ansatz for integrable U(1)N models in Lunin-Maldacena backgrounds
We obtain through a Matrix Product Ansatz (MPA) the exact solution of the most general N-state spin chain with U(1)N symmetry and nearest neighbour interaction. In the case N = 6 this model contain as a special case the integrable SO(6) spin chain related to the one loop mixing matrix for anomalous dimensions in N = 4 SYM, dual to type IIB string theory in t
Brazilian Journal of Physics. Publicado em: 2008-06
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8. Análogos de gravitação semi-clássica em física da matéria condensada / Analogue models of semi-classical gravity in condensate matter physics
This dissertation has as object of study systems of condensate-matter physics which can simulate gravitational systems like black holes and expanding universes where quantum processes take place. In this study we lay attention mainly on the fluid model and on Bose-Einstein-condensate-based models. In the fluid model we explore the features of the emergent ge
Publicado em: 2008
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9. Born-Infeld corrections to the entropy function of heterotic black holes
We use the black hole entropy function to study the effect of Born-Infeld terms on the entropy of extremal black holes in heterotic string theory in four dimensions. We find that after adding a set of higher curvature terms to the effective action, attractor mechanism works and Born-Infeld terms contribute to the stretching of near horizon geometry. In the a
Brazilian Journal of Physics. Publicado em: 2007-06
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10. Confinement by design?
The configuration space of SU(N) gauge theory is restricted to orbits with vanishing Polyakov loops of non-trivial N-ality. A practical method of constraining to this orbit space C0 is found by implementing a certain axial-type gauge. It is shown that the representative of an orbit in C0 is unique in this gauge up to time independent Abelian gauge transforma
Brazilian Journal of Physics. Publicado em: 2007-03
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11. Mechanism of Muscle Vibrations During Stimulated and Voluntary Isometric Contractions of Mammalian Skeletal Muscle
When a muscle contracts it produces vibrations. The origin of these vibrations is not known in detail. The purpose of this study was to determine the mechanism associated with muscle vibrations. Mechanisms which have been proposed in the literature were described as theories (cross-bridge cycling, vibrating string and unfused motor unit theories). Specific p
Publicado em: 2007
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12. Non-Riemannian geometry of twisted flux tubes
New examples of the theory recently proposed by Ricca [PRA(1991)] on the generalization of Da Rios-Betchov intrinsic equations on curvature and torsion of classical non-Riemannian vortex higher-dimensional string are given. In particular we consider applications to 3-dimesional fluid dynamics, including the case of a twisted flux tube and the fluid rotation.
Brazilian Journal of Physics. Publicado em: 2006-12