1,527 research outputs found
The Noncommutative Anandan's Quantum Phase
In this work we study the noncommutative nonrelativistic quantum dynamics of
a neutral particle, that possesses permanent magnetic and electric dipole
momenta, in the presence of an electric and magnetic fields. We use the
Foldy-Wouthuysen transformation of the Dirac spinor with a non-minimal coupling
to obtain the nonrelativistic limit. In this limit, we will study the
noncommutative quantum dynamics and obtain the noncommutative Anandan's
geometric phase. We analyze the situation where magnetic dipole moment of the
particle is zero and we obtain the noncommutative version of the
He-McKellar-Wilkens effect. We demonstrate that this phase in the
noncommutative case is a geometric dispersive phase. We also investigate this
geometric phase considering the noncommutativity in the phase space and the
Anandan's phase is obtained.Comment: 15 pages, revtex4, version to appear in Physical Review
Violation of the Ikeda sum rule and the self-consistency in the renormalized quasiparticle random phase approximation and the nuclear double-beta decay
The effect of the inclusion of ground state correlations into the QRPA
equation of motion for the two-neutrino double beta () decay
is carefully analyzed. The resulting model, called renormalized QRPA (RQRPA),
does not collapse near the physical value of the nuclear force strength in the
particle-particle channel, as happens with the ordinary QRPA. Still, the
transition amplitude is only slightly less sensitive on
this parameter in the RQRPA than that in the plain QRPA. It is argued that this
fact reveals once more that the characteristic behaviour of the
transition amplitude within the QRPA is not an artifact of
the model, but a consequence of the partial restoration of the spin-isospin
symmetry. It is shown that the price paid for bypassing the collapse in
the RQRPA is the violation of the Ikeda sum rule.Comment: 16 pages, latex, 3 postscript figure
Sensibilidade do carrapato Boophilus microplus a solventes.
A study was conducted to investigate the sensitivity of Boophilus microplus cattle ticks to different solvents. Larvae and engorged females of B. microplus were subjected to 7 solvents in 5 different concentrations in the presence and absence of olive oil. The utilization of olive oil did not produce different statistical results in the impregnated paper larval test. The same results were observed in the adult immersion test with hydrophilic compounds. The mean mortality caused by solvents was small in the larval test, and increased in immersion tests. Solvents with low molecular weight and viscosity such as alcohol and methyl alcohol did not affect the mortality of B. microplus in biological tests in concentrations below 76%.
Lorentz and CPT symmetries in commutative and noncommutative spacetime
We investigate the fermionic sector of a given theory, in which massive and
charged Dirac fermions interact with an Abelian gauge field, including a non
standard contribution that violates both Lorentz and CPT symmetries. We offer
an explicit calculation in which the radiative corrections due to the fermions
seem to generate a Chern-Simons-like effective action. Our results are obtained
under the general guidance of dimensional regularization, and they show that
there is no room for Lorentz and CPT violation in both commutative and
noncommutative spacetime.Comment: RevTex4, 7 pages, to be published in J. Phys.
The Effect of Steel Industrial Residue-Enriched Soil on the Initial Growth and Heavy Metal Profiles of Elephantgrass
Heavy metal contamination of industrial sites are becoming a matter of growing concern. In spite of the substantial progress in the assessment of the influence of steel industrial plant waste on soil and water (Adamo et al., 2002), studies on the immediate responses of cultivated plants are still scarce. The objective of this experiment was to verify the short-term effects of soil added phosphate mud (P mud) or metallurgical scale (M scale), which are trace element-rich steel industry residues, on the initial uptake and heavy metal profiles of elephantgrass (Pennisetum purpureum
Caracterização taxonômica de estirpes do gênero Bradyrhizobium isoladas de Centrolobium paraense
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