Epsilon(b) constrainsts on self-couplings of vector bosons

We analyze the constraints on possible anomalous contributions to the W+W-Z vertex coming from non-universal radiative corrections to the Z → bb̄ width. We parametrize these corrections in terms of ∈b and use the LEP data to establish the allowed values for the anomalous triple couplings. We examine all CP conserving effective operators that exhibit SU(2)L × U(1)Y gauge invariance and do not give any tree level contribution to the present experimental observables. For some of these operators our constraints are comparable with the bounds coming from a global fit of the oblique parameters, which evidences the increasing relevance of the precise measurement of the b-quark parameters at LEP for the search of new physics.

Conjuntos minimais e caóticos em campos de vetores planares suaves por partes

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

O espaço-tempo não comutativo em Teoria Quântica de Campos, Matéria Condensada Mole e Física Biológica

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Existência e concentração de soluções para uma equação de schrödinger estacionária

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Quantização de partículas com spin

Pós-graduação em Física - IFT

Construção exata de sólitons de Hopf

Pós-graduação em Física - IFT

Oscilador harmônico unidimensional via transformada unilateral de Fourier e mapeamento do potencial de morse unidimensional nos potenciais pseudo-harmônico e de kratzer tridimensionais

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Estudo de sistemas não-lineares em mecânica quântica

The main goal of this work is to investigate the effects of a nonlinear cubic term inserted in the Schrödinger equation for one-dimensional potentials studied in Quantum Mechanics textbooks. Being the main tool the numerical analysis in a large number of works, the analysis of this effect by this term in the potential itself, in order to work with an analytical solution, can be considered something new. For the harmonic oscillator potential, the analysis was made from a numerical method, comparing the result with the known results in the literature. In the case of the infinite well potential and the step potential, hoping to work with an analytical solution, by construction we started with the known wavefunction for the linear case noting the effects in the other physical quantities. The coupling of the physical quantities involved in this work has yielded, besides many complications in the calculations, a series of conditions on the existence and validity of the solutions in regard to the system possible configurations

MOLECULAR DYNAMICS STUDIES OF SIMPLE MODEL FLUIDS AND WATER CONFINED IN CARBON NANOTUBE

Molecular Dynamics (MD) simulation is one of the most important computational techniques with broad applications in physics, chemistry, chemical engineering, materials design and biological science. Traditional computational chemistry refers to quantum calculations based on solving Schrodinger equations. Later developed Density Functional Theory (DFT) based on solving Kohn-Sham equations became the more popular ab initio calculation technique which could deal with ~1000 atoms by explicitly considering electron interactions. In contrast, MD simulation based on solving classical mechanics equations of motion is a totally different technique in the field of computational chemistry. Electron interactions were implicitly included in the empirical atom-based potential functions and the system size to be investigated can be extended to ~106 atoms. The thermodynamic properties of model fluids are mainly determined by macroscopic quantities, like temperature, pressure, density. The quantum effects on thermodynamic properties like melting point, surface tension are not dominant. In this work, we mainly investigated the melting point, surface tension (liquid-vapor and liquid-solid) of model fluids including Lennard-Jones model, Stockmayer model and a couple of water models (TIP4P/Ew, TIP5P/Ew) by means of MD simulation. In addition, some new structures of water confined in carbon nanotube were discovered and transport behaviors of water and ions through nano-channels were also revealed.

THE INFLUENCE OF CHILDHOOD ABUSE ON LONGITUDINAL COURSE OF RECOVERY IN PSYCHIATRIC REHABILITATION

Background: Empirical outcome studies have identified specific symptomatic, cognitive, emotional and functional sequelae of childhood abuse in people with severe mental illness (SMI). These findings illuminate the need for an integrated understanding of biological, psychological, environmental, and developmental aspects of SMI. Purpose: The purpose of the present study includes the following: 1) to examine reliability and validity of the comprehensive child abuse rating system in a sample of individuals with SMI, 2) to examine the influence of childhood abuse severity on recovery of psychotic symptoms, neurocognition and social-cognition, and social functioning in people with SMI during 12 months of inpatient psychiatric rehabilitation, and 3) to examine moderating effects of social cognition on the relationship between severity of different types of child abuse history and social functioning. Results: In Study I (N=171), the child abuse rating system produced reliable ratings and some subtypes of child abuse history were related to poorer premorbid functioning and cognition, higher overall psychiatric symptoms, and lower social functioning. In Study II (N=161), the longitudinal factor pattern invariance of the measures of social functioning, externality, and psychiatric symptoms were confirmed across 3 time points (e.g., at admission, at 6 months, and at 12 months). In addition, significant but varied linear relationships between subtypes of child abuse and each level of assessment of functioning were identified. In Study III (N=143), the results showed that higher baseline social inference, independent of history of child physical abuse (CPA), played a protective role in improvements in social functioning. High externality appeared to be counter-therapeutic for individuals with no history of CPA but protective for individuals with a more severe history of CPA. Conclusion: The child abuse rating system appears to provide reliable and valid assessment of subtypes of child abuse history of individuals with SMI. Considering the extreme heterogeneity in both SMI and child maltreatment, the current finding sheds light on providing individualized treatment and assessment planning for individuals with SMI and a history of childhood abuse.

Oscilador harmônico unidimensional via transformada unilateral de Fourier e mapeamento do potencial de morse unidimensional nos potenciais pseudo-harmônico e de kratzer tridimensionais

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Estudo de sistemas não-lineares em mecânica quântica

The main goal of this work is to investigate the effects of a nonlinear cubic term inserted in the Schrödinger equation for one-dimensional potentials studied in Quantum Mechanics textbooks. Being the main tool the numerical analysis in a large number of works, the analysis of this effect by this term in the potential itself, in order to work with an analytical solution, can be considered something new. For the harmonic oscillator potential, the analysis was made from a numerical method, comparing the result with the known results in the literature. In the case of the infinite well potential and the step potential, hoping to work with an analytical solution, by construction we started with the known wavefunction for the linear case noting the effects in the other physical quantities. The coupling of the physical quantities involved in this work has yielded, besides many complications in the calculations, a series of conditions on the existence and validity of the solutions in regard to the system possible configurations

Effects of a CPT-even and Lorentz-violating nonminimal coupling on electron-positron scattering

We propose a new CPT-even and Lorentz-violating nonminimal coupling between fermions and Abelian gauge fields involving the CPT-even tensor (K-F)(mu nu alpha beta) of the standard model extension. We thus investigate its effects on the cross section of the electron-positron scattering by analyzing the process e(+) + e(-) -> mu(+) + mu(-). Such a study was performed for the parity-odd and parity-even nonbirefringent components of the Lorentz-violating (K-F)(mu nu alpha beta) tensor. Finally, by using experimental data available in the literature, we have imposed upper bounds as tight as 10(-12) (eV)(-1) on the magnitude of the CPT-even and Lorentz-violating parameters while nonminimally coupled. DOI: 10.1103/PhysRevD.86.125033

Anderson-like Transition for a Class of Random Sparse Models in d >= 2 Dimensions

We show that the Kronecker sum of d >= 2 copies of a random one-dimensional sparse model displays a spectral transition of the type predicted by Anderson, from absolutely continuous around the center of the band to pure point around the boundaries. Possible applications to physics and open problems are discussed briefly.