563 research outputs found
HFB calculations with a microscopic pairing interaction
Hartree-Fock-Bogolyubov (HFB) calculations making use of a recently proposed
microscopic effective pairing interaction are presented. The interaction was
shown to reproduce the pairing properties provided by the realistic
force very accurately in infinite matter. Although finite-ranged and non-local,
it makes 3D HFB calculations in coordinate space tractable. As a first
application, basic pairing properties of calcium isotopes in their ground-state
are studied. By comparing the results with those obtained using a standard
Density-Dependent Delta Interaction, the crucial isovector character of the
microscopic interaction is highlighted.Comment: 6 pages, 6 figures. Proceedings of the Conference on Nuclei at the
Limits, ANL, 2004. They will be published in the AIP Conference Proceedings
Serie
Pairing schemes for HFB calculations of nuclei
Several pairing schemes currently used to describe superfluid nuclei through
Hartree-Fock-Bogolyubov (HFB) calculations are briefly reviewed. We put a
particular emphasis on the regularization recipes used in connection with
zero-range forces and on the density dependence which usually complement their
definition. Regarding the chosen regularization process, the goal is not only
to identify the impact it may or may not have on pairing properties of nuclei
through spherical 1D HFB calculations but also to assess its tractability for
systematic axial 2D and 3D mean-field and beyond-mean-field calculations.Comment: 7 pages, 7 figures, Invited talk at the Workshop on New developments
in Nuclear Self-Consistent Mean-Field Theories, Yukawa Institute for
Theoretical Physics, Kyoto, Japan, May 30 - June 1, 2005, Yukawa Institute
for Theoretical Physics Report Series (Soryushi-ron kenkyu
Toward the Ab-initio Description of Medium Mass Nuclei
As ab-initio calculations of atomic nuclei enter the A=40-100 mass range, a
great challenge is how to approach the vast majority of open-shell (degenerate)
isotopes. We add realistic three-nucleon interactions to the state of the art
many-body Green's function theory of closed-shells, and find that physics of
neutron driplines is reproduced with very good quality. Further, we introduce
the Gorkov formalism to extend ab-initio theory to semi-magic, fully
open-shell, isotopes. Proof-of-principle calculations for Ca-44 and Ni-74
confirm that this approach is indeed feasible. Combining these two advances
(open-shells and three-nucleon interactions) requires longer, technical, work
but it is otherwise within reach.Comment: Contribution to Summary Report of EURISOL Topical and Town Meetings,
15-19 October 2012; missing affiliations added and corrected errors in Tab
Pairing in the Framework of the Unitary Correlation Operator Method (UCOM): Hartree-Fock-Bogoliubov Calculations
In this first in a series of articles, we apply effective interactions
derived by the Unitary Correlation Operator Method (UCOM) to the description of
open-shell nuclei, using a self-consistent Hartree-Fock-Bogoliubov framework to
account for pairing correlations. To disentangle the particle-hole and
particle-particle channels and assess the pairing properties of \VUCOM, we
consider hybrid calculations using the phenomenological Gogny D1S interaction
to derive the particle-hole mean field. In the main part of this article, we
perform calculations of the tin isotopic chain using \VUCOM in both the
particle-hole and particle-particle channels. We study the interplay of both
channels, and discuss the impact of non-central and non-local terms in
realistic interactions as well as the frequently used restriction of pairing
interactions to the partial wave. The treatment of the center-of-mass
motion and its effect on theoretical pairing gaps is assessed independently of
the used interactions.Comment: 14 pages, 10 figures, to appear in Phys. Rev. C, title modified
accordingl
Non-empirical pairing energy functional in nuclear matter and finite nuclei
We study 1S0 pairing gaps in neutron and nuclear matter as well as in finite
nuclei on the basis of microscopic two-nucleon interactions. Special attention
is paid to the consistency of the pairing interaction and normal self-energy
contributions. We find that pairing gaps obtained from low-momentum
interactions depend only weakly on approximation schemes for the normal
self-energy, required in present energy-density functional calculations, while
pairing gaps from hard potentials are very sensitive to the effective-mass
approximation scheme.Comment: 14 pages, 12 figures, published versio
Shape Coexistence in Pb186: Beyond-mean-field description by configuration mixing of symmetry restored wave functions
We study shape coexistence in Pb186 using configuration mixing of
angular-momentum and particle-number projected self-consistent mean-field
states. The same Skyrme interaction SLy6 is used everywhere in connection with
a density-dependent zero-range pairing force. The model predicts coexisting
spherical, prolate and oblate 0+ states at low energy.Comment: 5 pages REVTEX4, 4 eps figures, accepted by Phys. Lett. B. Revised
version with some polishing of the text without changing its conten
Skyrme mean-field study of rotational bands in transfermium isotopes
Self-consistent mean field calculations with the SLy4 interaction and a
density-dependent pairing force are presented for nuclei in the Nobelium mass
region. Predicted quasi-particle spectra are compared with experiment for the
heaviest known odd N and odd Z nuclei. Spectra and rotational bands are
presented for nuclei around No252,4 for which experiments are either planned or
already running.Comment: 13 pages LATEX, elsart style, 6 embedded eps figure
Towards heavy-mass ab initio nuclear structure: Open-shell Ca, Ni and Sn isotopes from Bogoliubov coupled-cluster theory
Recent developments in nuclear many-body theory enabled the description of
open-shell medium-mass nuclei from first principles by exploiting the
spontaneous breaking of symmetries within correlation expansion methods. Once
combined with systematically improvable inter-nucleon interactions consistently
derived from chiral effective field theory, modern ab initio nuclear structure
calculations provide a powerful framework to deliver first-principle
predictions accompanied with theoretical uncertainties. In this Letter,
controlled ab initio Bogoliubov coupled cluster calculations are performed for
the first time, targeting the ground-state of all calcium, nickel and tin
isotopes up to mass . While showing good agreement with available
experimental data, the shell structure evolution in neutron-rich isotopes and
the location of the neutron drip-lines are predicted.Comment: 7 pages, 5 figure
Chiral three-nucleon forces and pairing in nuclei
We present the first study of pairing in nuclei including three-nucleon
forces. We perform systematic calculations of the odd-even mass staggering
generated using a microscopic pairing interaction at first order in chiral
low-momentum interactions. Significant repulsive contributions from the leading
chiral three-nucleon forces are found. Two- and three-nucleon interactions
combined account for approximately 70% of the experimental pairing gaps, which
leaves room for self-energy and induced interaction effects that are expected
to be overall attractive in nuclei.Comment: 4 pages, 3 figure
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