On Matrix Superpotential and Three-Component Normal Modes

We consider the supersymmetric quantum mechanics (SUSY QM) with three- component normal modes for the Bogomol'nyi-Prasad-Sommerfield (BPS) states. An explicit form of the SUSY QM matrix superpotential is presented and the corresponding three-component bosonic zero-mode eigenfunction is investigated.Comment: 17 pages, no figure. Paper accepted for publication in Journal of Physics A: Mathematical and Theoretica

Nonrelativistic Quantum Analysis of the Charged Particle-Dyon System on a Conical Spacetime

In this paper we develop the nonrelativistic quantum analysis of the charged particle-dyon system in the spacetime produced by an idealized cosmic string. In order to do that, we assume that the dyon is superposed to the cosmic string. Considering this peculiar configuration {\it conical} monopole harmonics are constructed, which are a generalizations of previous monopole harmonics obtained by Wu and Yang(1976 {\it Nucl. Phys. B} {\bf 107} 365) defined on a conical three-geometry. Bound and scattering wave functions are explicitly derived. As to bound states, we present the energy spectrum of the system, and analyze how the presence of the topological defect modifies obtained result. We also analyze this system admitting the presence of an extra isotropic harmonic potential acting on the particle. We show that the presence of this potential produces significant changes in the energy spectrum of the system.Comment: Paper accepted for publication in Classical and Quantum Gravit

Influence of açai fruits (Euterpe oleracea Mart.) conservation on the acceptance of açai drink.

The açai drink is consumed habitually by populations of northern Brazil, but one of the major bottlenecks in the production of this drink is the seasonality of fruit production. Hence the needs to study the influence of cold storage on the transport of fruits from distant locations, such as the archipelago of Bailique (AP, Brazil) until the consumer centers. In this context, fruits collected and packaged under refrigeration and room temperatures were transported by boat for twelve hours and were subsequently processed in a mixer. Sensory analysis was performed in two consecutive days and the samples were stored under refrigeration. This analysis was performed by affective method with global acceptance (n=54) and the samples presented in a balanced way. It was used a hedonic scale with 9 points, ranging from like extremely (9) to dislike extremely (1). The results show that cold storage of the fruits affected significantly (p=0.002467) the acceptance of beverages in both two days of sensory evaluation. On the first day, the drink originated from fruits transported at cold storage received note 8 (liked a lot), while the drink from fruits at room temperature reached grade 7 (like moderately). On the second day of evaluation, the drink from refrigerated fruits received note 7 (like moderately) and drink from fruits stored at room temperature obtained note 5 (indifferent). Considering the type of preservation of fruits, no sensory difference was detected between the drinks from refrigerated fruits served on the two consecutive days, as well as no significant difference in drink of fruits transported at room temperature in this same period. It was concluded that açai fruits collected in regions distant from the consumer center, but kept under refrigeration, produce a drink with a considerable acceptance level, and they could be an alternative for supply of raw material during the off season.Resumo P1.5.010

Nonrelativistic Scattering Analysis of Charged Particle by a Magnetic Monopole in the Global Monopole Background

We analyze the nonrelativistic quantum scattering problem of a charged particle by an Abelian magnetic monopole in the background of a global monopole. In addition to the magnetic and geometric effects, we consider the influence of the electrostatic self-interaction on the charged particle. Moreover, for the specific case where the electrostatic self-interaction becomes attractive, charged particle-monopole bound system can be formed and the respective energy spectrum is hydrogen-like one.Comment: 10 pages. Contribution to the Proceedings of "2nd International Londrina Winter School Mathematical Methods in Physics". August 26-30, 2002, Londrina, PR, Brazi

Some boundary effects in quantum field theory

We have constructed a quantum field theory in a finite box, with periodic boundary conditions, using the hypothesis that particles living in a finite box are created and/or annihilated by the creation and/or annihilation operators, respectively, of a quantum harmonic oscillator on a circle. An expression for the effective coupling constant is obtained showing explicitly its dependence on the dimension of the box.Comment: 12 pages, Late

Present status of controversies regarding the thermal Casimir force

It is well known that, beginning in 2000, the behavior of the thermal correction to the Casimir force between real metals has been hotly debated. As was shown by several research groups, the Lifshitz theory, which provides the theoretical foundation for the calculation of both the van der Waals and Casimir forces, leads to different results depending on the model of metal conductivity used. To resolve these controversies, the theoretical considerations based on the principles of thermodynamics and new experimental tests were invoked. We analyze the present status of the problem (in particular, the advantages and disadvantages of the approaches based on the surface impedance and on the Drude model dielectric function) using rigorous analytical calculations of the entropy of a fluctuating field. We also discuss the results of a new precise experiment on the determination of the Casimir pressure between two parallel plates by means of a micromechanical torsional oscillator.Comment: 14 pages, 1 figure, iopart.cls is used, to appear in J. Phys. A (special issue: Proceedings of QFEXT05, Barcelona, Sept. 5-9, 2005