Effects of spin on the dynamics of the 2D Dirac oscillator in the magnetic cosmic string background

In this work the dynamics of a 2D Dirac oscillator in the spacetime of a magnetic cosmic string is considered. It is shown that earlier approaches to this problem have neglected a $\delta$ function contribution to the full Hamiltonian, which comes from the Zeeman interaction. The inclusion of spin effects leads to results which confirm a modified dynamics. Based on the self-adjoint extension method, we determined the most relevant physical quantities, such as energy spectrum, wave functions and the self-adjoint extension parameter by applying boundary conditions allowed by the system.Comment: 9 pages, 2 figures, published versio

The 2D κ\kappa-Dirac oscillator

In this Letter, 2D Dirac oscillator in the quantum deformed framework generated by the $\kappa$-Poincar\'{e}-Hopf algebra is considered. The problem is formulated using the $\kappa$-deformed Dirac equation. The resulting theory reveals that the energies and wave functions of the oscillator are modified by the deformation parameter.Comment: 4 pages, 2 figures, Accepted for publication in Physics Letters

Remarks on the Dirac oscillator in (2+1)(2+1) dimensions

In this work the Dirac oscillator in $(2+1)$ dimensions is considered. We solve the problem in polar coordinates and discuss the dependence of the energy spectrum on the spin parameter $s$ and angular momentum quantum number $m$. Contrary to earlier attempts, we show that the degeneracy of the energy spectrum can occur for all possible values of $sm$. In an additional analysis, we also show that an isolated bound state solution, excluded from Sturm-Liouville problem, exists.Comment: 5 pages, 2 figures, minor corrections, published versio

Quantum motion of a spinless particle in curved space: A viewpoint of scattering theory

In this work, we study the scattering of a spinless charged particle constrained to move on a curved surface in the presence of the Aharonov-Bohm potential. We begin with the equations of motion for the surface and transverse dynamics previously obtained in the literature (Ferrari G. and Cuoghi G., Phys. Rev. Lett. \textbf{100}, 230403 (2008)) and describe the surface with non-trivial curvature in terms of linear defects such as dislocations and disclinations. Expressions for the modified phase shift, S--matrix and scattering amplitude are determined by applying a suitable boundary condition at the origin, which comes from the self-adjoint extension theory. We also discuss the presence of a bound state obtained from the pole of the S--matrix. Finally, we claim that the bound state, the additional scattering and the dependence of the scattering amplitude with energy are solely due to the curvature effects.Comment: 9 pages, 1 figur

Government, Market and Development: Brazilian Economic Development in Historical Perspective

In the last 30 years the World has been swept by neoliberal doctrine. Under neoliberal conceptions, freedom of the market mechanism has precedence in the process of development. Neoliberalism has had a major impact on the mindset of policymakers, on government strategies for development and on economic performance. This thesis is about the economic consequences of neoliberalism in Brazil. It approaches the problem from a historical perspective. By examining government economic strategies in Brazil from the 1930s through the 1970s it undermines a central neoliberal argument that government interventions in the economy are either inimical or irrelevant to economic development. While government failures did occur indeed, in the Brazilian case it is shown that the government performed a crucial role in this period in building key institutions that guided market forces towards industrial transformation. Since the mid-1970s, Brazil has been a laboratory for neoliberal economic policymaking. Restrictive macroeconomic policies alongside liberalised markets have been the cornerstones of policymaking. The second line of argument developed here is that neoliberalism has since constrained economic development in Brazil. During this period the country has been through several financial crises and has experienced low economic growth and unprecedented unemployment. Compared with the previous period of government-led development, neoliberal policies and institutions fall far behind in terms of overall economic performance. Thirdly, it is argued that under neoliberalism government policy and institutions in Brazil have been directed to satisfy rentiers’ interests at the expense of a socially acceptable economic development. Finally, this thesis calls for the reinstatement of discussion over the government’s role as an agent of a democratic, economic and social ransformation. This is a discussion that has been obstructed by neoliberal doctrine for too long