Cleverson Filgueiras

Nonrelativistic quantum dynamics on a cone with and without a constraining potential

In this paper we investigate the bound state problem of nonrelativistic quantum particles on a conical surface. This kind of surface appears as a topological defect in ordinary semiconductors as well as in graphene sheets. Specifically, we compare and discuss the results stemming from two different approaches. In the first one, it is assumed that the charge carriers are bound to the surface by a constraining potential, while the second one is based on the Klein-Gordon type equation on surfaces, without the constraining potential. The main difference between both theories is the presence/absence of a potential which contains the mean curvature of a given surface. This fact changes the dependence of the bound states on the angular momentum l. Moreover, there are bound states that are absent in the Klein-Gordon theory, which instead appear in the Schrodinger one.

Yet another position-dependent mass quantum model

The quantum dynamics of particles with mass dependent on the position is a problem of interest since the effective-mass approach to charge carriers in conductors and semiconductors began to be used. These problems have been solved using the Hamiltonian H=12mα(x)pmβ(x)pmα(x), where α and β are real parameters which satisfy the condition 2α + β = −1. It has been verified that the choice α = 0, β = −1 is compatible with Galilean invariance. In this work we propose a new Hamiltonian, H=16m(x)−1p2+pm(x)−1p+p2m(x)−1, to describe variable mass systems. We considered every permutation among the operators, taking into account that the mass is now an operator. We verified that this Hamiltonian is Hermitian and is compatible with Galilean invariance. For comparison, we used both Hamiltonians to calculate the band structure for a quantum particle with mass varying periodically. Although qualitatively equivalent, the results turn out to produce different numerical values.

Landau quantization, Aharonov–Bohm effect and two-dimensional pseudoharmonic quantum dot around a screw dislocation

Abstract We investigate the influence of a screw dislocation on the energy levels and the wavefunctions of an electron confined in a two-dimensional pseudoharmonic quantum dot under the influence of an external magnetic field inside a dot and Aharonov–Bohm field inside a pseudodot. The exact solutions for energy eigenvalues and wavefunctions are computed as functions of applied uniform magnetic field strength, Aharonov–Bohm flux, magnetic quantum number and the parameter characterizing the screw dislocation, the Burgers vector. We investigate the modifications due to the screw dislocation on the light interband absorption coefficient and absorption threshold frequency. Two scenarios are possible, depending on if singular effects either manifest or not. We found that as the Burgers vector increases, the curves of frequency are pushed up towards of the growth of it. One interesting aspect which we have observed is that the Aharonov–Bohm flux can be tuned in order to cancel the screw effect of the model.

Effects of quantum deformation on the integer quantum Hall effect

In this work an application of the

Torsion effects on condensed matter: like a magnetic field but not so much

kappa

Scattering and Bound States of a Spin-1/2 Neutral Particle in the Cosmic String Spacetime

--deformed algebra in condensed matter physics is presented. Starting by the

Topological and non inertial effects on the interband light absorption

kappa

A Curved Noninteracting 2D Electron Gas with Anisotropic Mass

--deformed Dirac equation we study the relativistic generalization of the

Inertial and topological effects on a 2D electron gas

kappa

Relativistic quantum dynamics on a double cone

--deformed Landau levels as well as the consequences of the deformation on the Hall conductivity. By comparing the