265 research outputs found
Degeneracy and Para-supersymmetry of Dirac Hamiltonian in (2+1)- Spacetime
The quantum mechanics of a spin 1/2 particle on a locally spatial constant
curvature part of a (2+1)- spacetime in the presence of a constant magnetic
field of a magnetic monopole has been investigated. It has been shown that
these 2-dimensional Hamiltonians have the degeneracy group of SL(2,c), and
para-supersymmetry of arbitrary order or shape invariance. Using this symmetry
we have obtained its spectrum algebraically. The Dirac's quantization condition
has been obtained from the representation theory. Also, it is shown that the
presence of angular deficit suppresses both the degeneracy and shape
invariance.Comment: 31 pages, Latex, no figures, to be published in J. Math. Phy
Neonatal Seizure: Etiology and Type
ObjectiveNeonates, for many reasons, are at particular risk for the development of seizures, which are a strong predictor of later morbidity and mortality in infants.We undertook this study to determine the incidence, etiologic distribution and neonatal seizure type in neonates with hospital admission over a period of 4 years.Materials and MethodsThis, a retrospective study of newborns admitted in hospital with a diagnosis of neonatal seizures, was conducted over a 4 year period between March 2001 and March 2005.Data were obtained from hospital records was analyzed using the Chi-square test.ResultsOf 4541 newborns, admitted to hospital, during the study period, seizures occurred in 110 neonates. The incidence of neonatal seizures was 2.4%; the causes of neonatal seizure were Hypoxic-Ischemic Encephalopathy (HIE) - 36.4%, infections -19.1%, metabolic abnormalities - 7.3%, Intra Cranial Hemorrhage (ICH) - 2.7%, structural disorders - 1.8% and in 32.7% of cases, the cause was unknown.Subtle seizures (39.1%) were the most common type of seizures; and the other types were myoclonic (17.3%), clonic (10.0%), Tonic (7.3%), Generalized Tonic Clonic Seizures (GTCS) (12.7%) and in 13.6% of cases the type of seizure was not mentioned. Mortality rate was 13.6%.ConclusionHealth care workers and parents need to be made aware of subtle seizures and the importance of timely and appropriate treatment to decrease any further complications
Formulation of Electrodynamics with an External Source in the Presence of a Minimal Measurable Length
In a series of papers, Quesne and Tkachuk (J. Phys. A: Math. Gen.
\textbf{39}, 10909 (2006); Czech. J. Phys. \textbf{56}, 1269 (2006)) presented
a -dimensional -two-parameter Lorentz-covariant deformed
algebra which leads to a nonzero minimal measurable length. In this paper, the
Lagrangian formulation of electrodynamics in a 3+1-dimensional space-time
described by Quesne-Tkachuk algebra is studied in the special case
up to first order over the deformation parameter . It is
demonstrated that at the classical level there is a similarity between
electrodynamics in the presence of a minimal measurable length (generalized
electrodynamics) and Lee-Wick electrodynamics. We obtain the free space
solutions of the inhomogeneous Maxwell's equations in the presence of a minimal
length. These solutions describe two vector particles (a massless vector
particle and a massive vector particle). We estimate two different upper bounds
on the isotropic minimal length. The first upper bound is near to the
electroweak length scale , while the
second one is near to the length scale for the strong interactions
. The relationship between the
Gaete-Spallucci nonlocal electrodynamics (J. Phys. A: Math. Theor. \textbf{45},
065401 (2012)) and electrodynamics with a minimal length is investigated.Comment: 13 pages, no figur
Exact solutions of Dirac equation on (1+1)-dimensional spacetime coupled to a static scalar field
We use a generalized scheme of supersymmetric quantum mechanics to obtain the
energy spectrum and wave function for Dirac equation in (1+1)-dimensional
spacetime coupled to a static scalar field.Comment: 7 pages, Late
Formulation of an Electrostatic Field with a Charge Density in the Presence of a Minimal Length Based on the Kempf Algebra
In a series of papers, Kempf and co-workers (J. Phys. A: Math. Gen. {\bf 30},
2093, (1997); Phys. Rev. D {\bf52}, 1108, (1995); Phys. Rev. D {\bf55}, 7909,
(1997)) introduced a D-dimensional -two-parameter deformed
Heisenberg algebra which leads to a nonzero minimal observable length. In this
work, the Lagrangian formulation of an electrostatic field in three spatial
dimensions described by Kempf algebra is studied in the case where
up to first order over deformation parameter . It is
shown that there is a similarity between electrostatics in the presence of a
minimal length (modified electrostatics) and higher derivative Podolsky's
electrostatics. The important property of this modified electrostatics is that
the classical self-energy of a point charge becomes a finite value. Two
different upper bounds on the isotropic minimal length of this modified
electrostatics are estimated. The first upper bound will be found by treating
the modified electrostatics as a classical electromagnetic system, while the
second one will be estimated by considering the modified electrostatics as a
quantum field theoretic model. It should be noted that the quantum upper bound
on the isotropic minimal length in this paper is near to the electroweak length
scale .Comment: 11 pages, no figur
Families of exact solutions of a 2D gravity model minimally coupled to electrodynamics
Three families of exact solutions for 2-dimensional gravity minimally coupled
to electrodynamics are obtained in the context of theory. It is
shown, by supersymmetric formalism of quantum mechanics, that the quantum
dynamics of a neutral bosonic particle on static backgrounds with both varying
curvature and electric field is exactly solvable.Comment: 13 pages, LaTeX, to be published in JM
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