Effects of quantum deformation on the spin-1/2 Aharonov-Bohm problem

In this letter we study the Aharonov-Bohm problem for a spin-1/2 particle in the quantum deformed framework generated by the $\kappa$-Poincar\'{e}-Hopf algebra. We consider the nonrelativistic limit of the $\kappa$-deformed Dirac equation and use the spin-dependent term to impose an upper bound on the magnitude of the deformation parameter $\varepsilon$. By using the self-adjoint extension approach, we examine the scattering and bound state scenarios. After obtaining the scattering phase shift and the $S$-matrix, the bound states energies are obtained by analyzing the pole structure of the latter. Using a recently developed general regularization prescription [Phys. Rev. D. \textbf{85}, 041701(R) (2012)], the self-adjoint extension parameter is determined in terms of the physics of the problem. For last, we analyze the problem of helicity conservation.Comment: 12 pages, no figures, submitted for publicatio

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

Remarks on the Aharonov-Casher dynamics in a CPT-odd Lorentz-violating background

The Aharonov-Casher problem in the presence of a Lorentz-violating background nonminimally coupled to a spinor and a gauge field is examined. Using an approach based on the self-adjoint extension method, an expression for the bound state energies is obtained in terms of the physics of the problem by determining the self-adjoint extension parameter.Comment: Matches published versio

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

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

Intergovernmental grant rules, the "golden rule" of public finance and local expenditures

The Stability and Growth Pact and the process of fiscal consolidation in several European countries have enhanced the role of fiscal rules at sub-national level. This paper analyzes the combined effect of a rule to allocate capital and current block grants to local governments and the “golden rule” of public finance (surplus of current balance). We argue that the two fiscal rules introduce significant rigidities and distortions in local governments’ expenditures structure since these mimic the structure of revenues. This effect is particularly relevant in municipalities that are more dependent of intergovernmental grants, mainly rural. On the other hand, urban municipalities with greater tax revenues (current revenues) are constrained in their ability to make capital investments because they receive per capita capital grants below what economies of scale would suggest. An empirical analysis of Portuguese local governments shows that it is no longer the median voter, but fiscal rules, that command the broad pattern of expenditure (current versus capital) at a local level. This paper is a contribution to the literature on the perverse effects of fiscal rules.Intergovernmental block grants; Fiscal Rules; Local Government Expenditure; “Golden Rule”

Citizens’ Freedom to Choose Representatives: Ballot Structure, Proportionality and “Fragmented” Parliaments

The analysis of the political consequences of electoral laws has emphasized how individual characteristics of the electoral system (electoral formulas, district magnitude, ballot structure) affect the degree of parliament “fragmentation” and proportionality. This paper argues that the personal attributes of representatives are also an important consequence of electoral laws, and that they are in part determined by citizens’ freedom to choose representatives. We clarify this concept and develop an index of citizens’ freedom to choose members of parliament as a function of the ballot structure, district size and electoral formulae. Using data from twenty nine countries, we find that neither proportionality nor the effective number of parties is significantly affected by voters’ freedom of choice. This result has important normative implications for electoral reform.Ballot structure; Electoral index; Freedom to choose; Personal vote.