45,794 research outputs found
Relativistic description of magnetic moments in nuclei with doubly closed shells plus or minus one nucleon
Using the relativistic point-coupling model with density functional PC-PK1,
the magnetic moments of the nuclei Pb, Pb, Tl and
Bi with a closed-shell core Pb are studied on the basis of
relativistic mean field (RMF) theory. The corresponding time-odd fields, the
one-pion exchange currents, and the first- and second-order corrections are
taken into account. The present relativistic results reproduce the data well.
The relative deviation between theory and experiment for these four nuclei is
6.1% for the relativistic calculations and somewhat smaller than the value of
13.2% found in earlier non-relativistic investigations. It turns out that the
meson is important for the description of magnetic moments, first by
means of one-pion exchange currents and second by the residual interaction
provided by the exchange.Comment: 11 pages, 7 figure
Glauber-based evaluations of the odd moments of the initial eccentricity relative to the even order participant planes
Monte Carlo simulations are used to compute the centrality dependence of the
odd moments of the initial eccentricity , relative to the even
order (n) participant planes in Au+Au collisions. The results
obtained for two models of the eccentricity -- the Glauber and the factorized
Kharzeev-Levin-Nardi (fKLN) models -- indicate magnitudes which are essentially
zero. They suggest that a possible correlation between the orientations of the
the odd and even participant planes ( and
respectively), do not have a significant influence on the calculated
eccentricities. An experimental verification test for correlations between the
orientations of the the odd and even participant planes is also proposed.Comment: 3 pages, 1 figure. Version accepted for publicatio
Functional Forms for the Squeeze and the Time-Displacement Operators
Using Baker-Campbell-Hausdorff relations, the squeeze and harmonic-oscillator
time-displacement operators are given in the form , where ,
, , and are explicitly determined. Applications are
discussed.Comment: 10 pages, LaTe
A nonlocal eigenvalue problem and the stability of spikes for reaction-diffusion systems with fractional reaction rates
We consider a nonlocal eigenvalue problem which arises in the study of stability of spike solutions for reaction-diffusion systems with
fractional reaction rates such as the Sel'kov model, the
Gray-Scott system, the hypercycle Eigen and Schuster, angiogenesis, and the generalized Gierer-Meinhardt
system.
We give some sufficient and explicit conditions for stability
by studying the corresponding nonlocal eigenvalue problem in a new
range of parameters
- âŚ