Finite Temperature Field Theory
Mostrando 1-12 de 15 artigos, teses e dissertações.
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1. László Tisza, 110 anos: Origens da Física Térmica Moderna
Resumo A axiomática de László Tisza da termodinâmica é revisitada, identificada a partir de cinco elementos constitutivos, e incluída em uma perspectiva histórica. Através de uma definição de medida, uma análise detalhada da associação do formalismo de Tisza com o experimento é conduzida. A ênfase da apresentação é para a relação da axiom
Rev. Bras. Ensino Fís.. Publicado em: 10/01/2019
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2. Robust Optimal Control Applied to a Composite Laminated Beam
ABSTRACT: This paper proposes an active vibration control technique, which is based on linear matrix inequalities, that is applied to a piezoelectric actuator bonded to a composite structure, forming a so-called smart composite structure. Serendipity-type finite element, based on first-order shear deformation theory with rectangular shape, eight nodes, five
J. Aerosp. Technol. Manag.. Publicado em: 2015-03
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3. Effects of spontaneous symmetry breaking-CPT and Lorentz invariance of the phenomenon the Bose-Einstein / Efeitos da quebra espontânea da simetria-CPT e da invariância de Lorentz no fenômeno da condensação de Bose-Einstein
The Bose-Einstein condensate (BEC), also known as the fifth state of the matter, was predicted theoretically by Albert Einstein in 1925 and verified experimentally 70 years later in 1995. This dissertation addresses the effects of spontaneous broken of the CPT-symmetry and of the invariance Lorentz (also called simply the violation of Lorentz symmetry) in th
Publicado em: 2011
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4. Violação de Lorentz e teoria de gravitação modificada
In this thesis we study the Lorentz and CPT symmetries breaking in a 4D fourfermions model at zero and at finite temperature. At zero temperature we find that these symmetries can be violated, but at finite temperature we show that there is a critical temperature at which the Lorentz and CPT symmetries are restored. We show that it is possible obtain the Fri
Publicado em: 2010
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5. Estudo comparativo entre teoria construtal e entrânsia para casos de resfriamento de fontes de calor em cavidade / Comparactive study between constructal theory end the entransy treory for the cooling cases of heat sources in a cavity
In the present work the cooling was treated by natural convection of one, three and five sources localized in a vertical wall of a rectangular cavity. One has approximated numerically the temperature field in the stationary state at different positions for each case. The conductivity and the dissipation of entransy were evaluated in all these cases and their
Publicado em: 2009
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6. Topologia, Simetria e transições de fase em Modelos de Spin
We use a topological approach to describe the frustration- and field-induced phase transitions exhibited by the infinite-range XY model on the AB2 chain, including noncollinear spin structures. For this purpose, we have computed the Morse number and the Euler characteristic, as well as other topological invariants, which are found to behave similarly as func
Publicado em: 2009
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7. Thermodynamic properties of the field electromagnetic field in the CPT-odd standard extended / Propriedades termodinâmicas do campo eletromagnético no setor CPT-ımpar do modelo padrão estendido
In this work we study the effects of the spontaneous breaking of Lorentz symmetry on black body radiation phenomenon in the context of the Maxwell-Caroll-Field-Jackiw (MCFJ) model. The MCFJ model is the electromagnetic CPT-odd sector of the standard model extension and, it presents for a purely space-like background a positive-definite hamiltonian. Firstly,
Publicado em: 2009
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8. Different symmetry realizations in relativistic coupled bose systems at finite temperature and densities
We revisited the calculation of the effective potential for self-interacting scalar field with U (1) charge at one loop approximation. We show that high charge densities can induce important changes in the phase structure of the theory. A class of very interesting phenomena appear when we introduce finite density effects, e.g. symmetry nonrestoration, invers
Brazilian Journal of Physics. Publicado em: 2008-09
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9. An euclidean approach as a method to study the Unruh effect / Uma estratégia euclidiana para o estudo do efeito Unruh
This paper proposes a Euclidean strategy to understand the Unruh effect. On that ground we first study it for free massless scalar fields the way it is usually presented to pliysicists, which is closer to Unruhs original work [32]. Then we infer the effect from an algebraic perspective. We study the proprieties and definitions of KklS states in order to unde
Publicado em: 2007
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10. Remarks on Lorentz and CPT violation in field theory
In this brief review we explicitly calculate the radiative corrections to the Chern-Simons-like term in the cases of zero and finite temperature, and in the gravity theory. Our results are obtained under the general guidance of dimensional regularization.
Brazilian Journal of Physics. Publicado em: 2006-12
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11. Modelagem por elementos finitos de placas compostas dotadas de sensores e atuadores piezoelÃtricos : implementaÃÃo computacional e avaliaÃÃo numÃrica / Finite element modeling of composite plates incorporating piezoelectric sensors and actuators: implementation and numerical assessment
This Dissertation presents a methodology based on the Finite Element method for the modeling of laminated composite beams and plates containing piezoelectric sensors and actuators. The fundamental concepts and the theoretical developments are presented, followed by a number of numerical simulations performed in MATLABÂ environment. The finite element used i
Publicado em: 2006
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12. Efeitos de temperatura e de interação finita em sistemas desordenados correlacionados
The main goal of this work is to study the role of disorder in strongly correlated systems, where the electron-electron interaction is comparable to or dominates over the electron kinetic energy. Keeping this in mind, we solve the Hubbard model and the Anderson lattice model in the presence of disorder. The main theory in which our work is based is the Dynam
Publicado em: 2003