158 research outputs found
Time-odd mean fields in the rotating frame: microscopic nature of nuclear magnetism
The microscopic role of nuclear magnetism in rotating frame is investigated
for the first time in the framework of the cranked relativistic mean field
theory. It is shown that nuclear magnetism modifies the expectation values of
single-particle spin, orbital and total angular momenta along the rotational
axis effectively creating additional angular momentum. This effect leads to the
increase of kinematic and dynamic moments of inertia at given rotational
frequency and has an impact on effective alignments.Comment: 16 pages, 4 figures, submitted to Physical Review
A comparative study of super- and highly-deformed bands in the A ~ 60 mass region
Super- and highly-deformed rotational bands in the A ~ 60 mass region are
studied within cranked relativistic mean field theory and the
configuration-dependent shell-correction approach based on the cranked Nilsson
potential. Both approaches describe the experimental data well. Low values of
the dynamic moments of inertia J^(2) compared with the kinematic moments of
inertia J^(1) seen both in experiment and in calculations at high rotational
frequencies indicate the high energy cost to build the states at high spin and
reflect the limited angular momentum content in these configurations.Comment: 11 pages, 4 PostScript figures, Latex, uses 'epsf', submitted to
Phys. Lett.
Properties of nuclei in the nobelium region studied within the covariant, Skyrme, and Gogny energy density functionals
We calculate properties of the ground and excited states of nuclei in the
nobelium region for proton and neutron numbers of 92 <= Z <= 104 and 144 <= N
<= 156, respectively. We use three different energy-density-functional (EDF)
approaches, based on covariant, Skyrme, and Gogny functionals, each within two
different parameter sets. A comparative analysis of the results obtained for
odd-even mass staggerings, quasiparticle spectra, and moments of inertia allows
us to identify single-particle and shell effects that are characteristic to
these different models and to illustrate possible systematic uncertainties
related to using the EDF modellingComment: 43 LaTeX pages, 14 figures, accepted in Nuclear Physics A, Special
Issue on Superheavy Element
Moments of Inertia of Nuclei in the Rare Earth Region: A Relativistic versus Non-Relativistic Investigation
A parameter free investigation of the moments of inertia of ground state
rotational bands in well deformed rare-earth nuclei is carried out using
Cranked Relativistic Hartree-Bogoliubov (CRHB) and non-relativistic Cranked
Hartree-Fock-Bogoliubov (CHFB) theories. In CRHB theory, the relativistic
fields are determined by the non-linear Lagrangian with the NL1 force and the
pairing interaction by the central part of finite range Gogny D1S force. In
CHFB theory, the properties in particle-hole and particle-particle channels are
defined solely by Gogny D1S forces. Using an approximate particle number
projection before variation by means of the Lipkin Nogami method improves the
agreement with the experimental data, especially in CRHB theory. The effect of
the particle number projection on the moments of inertia and pairing energies
is larger in relativistic than in non-relativistic theory.Comment: 18 pages + 2 PostScript figure
Cranked Relativistic Hartree-Bogoliubov Theory: Superdeformed Bands in the Region
Cranked Relativistic Hartree-Bogoliubov (CRHB) theory is presented as an
extension of Relativistic Mean Field theory with pairing correlations to the
rotating frame. Pairing correlations are taken into account by a finite range
two-body force of Gogny type and approximate particle number projection is
performed by Lipkin-Nogami method. This theory is applied to the description of
yrast superdeformed rotational bands observed in even-even nuclei of the mass region. Using the well established parameter sets NL1 for the
Lagrangian and D1S for the pairing force one obtains a very successful
description of data such as kinematic () and dynamic ()
moments of inertia without any adjustment of new parameters. Within the present
experimental accuracy the calculated transition quadrupole moments agree
reasonably well with the observed data.Comment: 6 pages including 4 PostScript figures, uses RevTex, revised version,
Phys.Rev. C, Rapid Communications, in pres
Ultra-short solitons and kinetic effects in nonlinear metamaterials
We present a stability analysis of a modified nonlinear Schroedinger equation
describing the propagation of ultra-short pulses in negative refractive index
media. Moreover, using methods of quantum statistics, we derive a kinetic
equation for the pulses, making it possible to analyze and describe partial
coherence in metamaterials. It is shown that a novel short pulse soliton, which
is found analytically, can propagate in the medium.Comment: 6 pages, 2 figures, to appear in Phys. Rev.
Very high rotational frequencies and band termination in 73Br
Rotational bands in 73Br have been investigated up to spins of 65/2 using the
EUROBALL III spectrometer. One of the negative-parity bands displays the
highest rotational frequency 1.85 MeV reported to date in nuclei with mass
number greater than 25. At high frequencies, the experimental dynamic moment of
inertia for all bands decrease to very low values, indicating a loss of
collectivity. The bands are described in the configuration-dependent cranked
Nilsson-Strutinsky model. The calculations indicate that one of the
negative-parity bands is observed up to its terminating single-particle state
at spin 63/2. This result establishes the first band termination case in the A
= 70 mass region.Comment: 6 pages, 6 figures, submitted to Phys. Rev. C as a Rapid
Communicatio
A New Parameterization for the Lagrangian Density of Relativistic Mean Field Theory
A new parameterization for an effective non-linear Lagrangian density of
relativistic mean field (RMF) theory is proposed, which is able to provide an
excellent description not only for the properties of stable nuclei but also for
those far from the valley of beta-stability. In addition recently measured
superdeformed mimima in the Hg-region are reproduced with high accuracy.Comment: 8 pages, Latex, 1 ps figur
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