An alternative factorization of the quantum harmonic oscillator and two-parameter family of self-adjoint operators

We introduce an alternative factorization of the Hamiltonian of the quantum harmonic oscillator which leads to a two-parameter self-adjoint operator from which the standard harmonic oscillator, the one-parameter oscillators introduced by Mielnik, and the Hermite operator are obtained in certain limits of the parameters. In addition, a single Bernoulli-type parameter factorization which is different of the one introduced by M. A. Reyes, H. C. Rosu, and M. R. Gutierrez, Phys. Lett. A 375 (2011) 2145 is briefly discussed in the final part of this workComment: 18 pages, 7 figures, last 2 figures are not included in the version to be published, accepted by Phys. Lett.

Piezoelectric vs. Capacitive Based Force Sensing in Capacitive Touch Panels

High sensitivity force sensing is a desirable function of capacitance touch screen panels. In this paper, we report on a dynamic force detection technique by utilizing piezoelectric materials. The force-voltage responsivities are investigated for four widely used stack-ups, with various panel thicknesses and touch locations. Based on the theoretical analysis and simulation results, the maximum responsivity and the signal-to-noise ratio are achieved at 0.42 V/N and 59.1 dB, respectively. The proposed technique implements force sensing successfully, enhancing the human-machine interactivity experience

Vibrating soap films: An analog for quantum chaos on billiards

We present an experimental setup based on the normal modes of vibrating soap films which shows quantum features of integrable and chaotic billiards. In particular, we obtain the so-called scars -narrow linear regions with high probability along classical periodic orbits- for the classically chaotic billiards. We show that these scars are also visible at low frequencies. Finally, we suggest some applications of our experimental setup in other related two-dimensional wave phenomena.Comment: 5 pages, 7 figures. Better Postscript figures available on reques

Torsion and Gravitation: A new view

According to the teleparallel equivalent of general relativity, curvature and torsion are two equivalent ways of describing the same gravitational field. Despite equivalent, however, they act differently: whereas curvature yields a geometric description, in which the concept of gravitational force is absent, torsion acts as a true gravitational force, quite similar to the Lorentz force of electrodynamics. As a consequence, the right-hand side of a spinless-particle equation of motion (which would represent a gravitational force) is always zero in the geometric description, but not in the teleparallel case. This means essentially that the gravitational coupling prescription can be minimal only in the geometric case. Relying on this property, a new gravitational coupling prescription in the presence of curvature and torsion is proposed. It is constructed in such a way to preserve the equivalence between curvature and torsion, and its basic property is to be equivalent with the usual coupling prescription of general relativity. According to this view, no new physics is connected with torsion, which appears as a mere alternative to curvature in the description of gravitation. An application of this formulation to the equations of motion of both a spinless and a spinning particle is madeComment: To appear on IJMP

Manual de laboratorio Calosa como herramienta de selecci�n para tolerancia del ma�z al aluminio

Zea mays, calosa, herencia, dialelo, heterosis, m�todos de selecci�n, suelos �cidos, germoplasma, Colombia, Crop Production/Industries, F30,