17,722 research outputs found
Quasi-exactly-solvable confining solutions for spin-1 and spin-0 bosons in (1+1)-dimensions with a scalar linear potential
We point out a misleading treatment in the recent literature regarding
confining solutions for a scalar potential in the context of the
Duffin-Kemmer-Petiau theory. We further present the proper bound-state
solutions in terms of the generalized Laguerre polynomials and show that the
eigenvalues and eigenfunctions depend on the solutions of algebraic equations
involving the potential parameter and the quantum number.Comment: 8 pages, 1 figur
Orthogonality criterion for banishing hydrino states from standard quantum mechanics
Orthogonality criterion is used to shown in a very simple and general way
that anomalous bound-state solutions for the Coulomb potential (hydrino states)
do not exist as bona fide solutions of the Schr\"{o}dinger, Klein-Gordon and
Dirac equations.Comment: 6 page
Exact Solutions of the Dirac Equation for Modified Coulombic Potentials
Exact solutions are found to the Dirac equation for a combination of Lorentz
scalar and vector Coulombic potentials with additional non-Coulombic parts. An
appropriate linear combination of Lorentz scalar and vector non-Coulombic
potentials, with the scalar part dominating, can be chosen to give exact
analytic Dirac wave functions. The method works for the ground state or for the
lowest orbital state with l=j-{1/2}, for any j.Comment: 7 pages, Latex fil
Soil solarization for weed control in carrot.
Soil solarization is a technique used for weed and plant disease control in regions with high levels of solar radiation. The effect of solarization (0, 3, 6, and 9 weeks) upon weed populations,carrot (Daucus carota L. cv. BrasĂlia) yield and nematode infestation in carrot roots was studied in SĂŁo LuĂs (2o35' S; 44o10' W), MA, Brazil, using transparent polyethylene films (100 and 150 mm of thickness). The maximum temperature at 5 cm of depth was about 10oC warmer in solarized soil than in control plots. In the study 20 weed types were recorded. Solarization reduced weed biomass and density in about 50% of weed species, including Cyperus spp., Chamaecrista nictans var. paraguariensis(Chod & Hassl.) Irwin & Barneby,Marsypianthes chamaedrys (Vahl) O. Kuntze, Mitracarpus sp.,Mollugo verticillata L., Sebastiania corniculata M. Arg., and Spigelia anthelmia L. Approximately 40% of species in the weed flora were not affected by soil mulching. Furthermore, seed germination of Commelina benghalensis L. was increased by soil solarization. Marketable yield of carrots was greater in solarized soil than in the unsolarized one. It was concluded that solarization for nine weeks increases carrot yield and is effective for controlling more than half of the weed species recorded. Mulching was not effective for controlling root-knot nematodes in carrot
Confinement of neutral fermions by a pseudoscalar double-step potential in (1+1) dimensions
The problem of confinement of neutral fermions in two-dimensional space-time
is approached with a pseudoscalar double-step potential in the Dirac equation.
Bound-state solutions are obtained when the coupling is of sufficient
intensity. The confinement is made plausible by arguments based on effective
mass and anomalous magnetic interaction.Comment: 8 pages, 1 figur
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