854 research outputs found
Reply to comment ``On the test of the modified BCS at finite temperature''
This is our formal Reply to revised version (v2) of arXiv: nucl-th/0510004v2.Comment: accepted in Physical Review
Test of modified BCS model at finite temperature
A recently suggested modified BCS (MBCS) model has been studied at finite
temperature. We show that this approach does not allow the existence of the
normal (non-superfluid) phase at any finite temperature. Other MBCS predictions
such as a negative pairing gap, pairing induced by heating in closed-shell
nuclei, and ``superfluid -- super-superfluid'' phase transition are discussed
also. The MBCS model is tested by comparing with exact solutions for the picket
fence model. Here, severe violation of the internal symmetry of the problem is
detected. The MBCS equations are found to be inconsistent. The limit of the
MBCS applicability has been determined to be far below the ``superfluid --
normal'' phase transition of the conventional FT-BCS, where the model performs
worse than the FT-BCS.Comment: 8 pages, 9 figures, to appear in PR
Self-consistent calculations of quadrupole moments of the first 2+ states in Sn and Pb isotopes
A method of calculating static moments of excited states and transitions
between excited states is formulated for non-magic nuclei within the Green
function formalism. For these characteristics, it leads to a noticeable
difference from the standard QRPA approach. Quadrupole moments of the first 2+
states in Sn and Pb isotopes are calculated using the self-consistent TFFS
based on the Energy Density Functional by Fayans et al. with the set of
parameters DF3-a fixed previously. A reasonable agreement with available
experimental data is obtained.Comment: 5 pages, 6 figure
Inelastic neutrino scattering off hot nuclei in supernova environments
We study inelastic neutrino scattering off hot nuclei for temperatures
relevant under supernova conditions. The method we use is based on the
quasiparticle random phase approximation extended to finite temperatures within
the thermo field dynamics (TQRPA). The method allows a transparent treatment of
upward and downward transitions in hot nuclei, avoiding the application of
Brink's hypothesis. For the sample nuclei Fe and Ge we perform a
detailed analysis of thermal effects on the strength distributions of allowed
Gamow-Teller (GT) transitions which dominate the scattering process at low
neutrino energies. For Fe and Ge the finite temperature
cross-sections are calculated by taking into account the contribution of
allowed and forbidden transitions. The observed enhancement of the
cross-section at low neutrino energies is explained by considering thermal
effects on the GT strength. For Fe we compare the calculated
cross-sections to those obtained earlier from a hybrid approach that combines
large-scale shell-model and RPA calculations.Comment: 12 pages, 9 figure
Ground state correlations and structure of odd spherical nuclei
It is well known that the Pauli principle plays a substantial role at low
energies because the phonon operators are not ideal boson operators.
Calculating the exact commutators between the quasiparticle and phonon
operators one can take into account the Pauli principle corrections. Besides
the ground state correlations due to the quasiparticle interaction in the
ground state influence the single particle fragmentation as well. In this
paper, we generalize the basic QPM equations to account for both mentioned
effects. As an illustration of our approach, calculations on the structure of
the low-lying states in Ba have been performed.Comment: 12 pages, 1 figur
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