15,435 research outputs found
Self-consistent relativistic quasiparticle random-phase approximation and its applications to charge-exchange excitations and -decay half-lives
The self-consistent quasiparticle random-phase approximation (QRPA) approach
is formulated in the canonical single-nucleon basis of the relativistic
Hatree-Fock-Bogoliubov (RHFB) theory. This approach is applied to study the
isobaric analog states (IAS) and Gamov-Teller resonances (GTR) by taking Sn
isotopes as examples. It is found that self-consistent treatment of the
particle-particle residual interaction is essential to concentrate the IAS in a
single peak for open-shell nuclei and the Coulomb exchange term is very
important to predict the IAS energies. For the GTR, the isovector pairing can
increase the calculated GTR energy, while the isoscalar pairing has an
important influence on the low-lying tail of the GT transition. Furthermore,
the QRPA approach is employed to predict nuclear -decay half-lives. With
an isospin-dependent pairing interaction in the isoscalar channel, the
RHFB+QRPA approach almost completely reproduces the experimental -decay
half-lives for nuclei up to the Sn isotopes with half-lives smaller than one
second. Large discrepancies are found for the Ni, Zn, and Ge isotopes with
neutron number smaller than , as well as the Sn isotopes with neutron
number smaller than . The potential reasons for these discrepancies are
discussed in detail.Comment: 34 pages, 14 figure
Nuclear /EC decays in covariant density functional theory and the impact of isoscalar proton-neutron pairing
Self-consistent proton-neutron quasiparticle random phase approximation based
on the spherical nonlinear point-coupling relativistic Hartree-Bogoliubov
theory is established and used to investigate the /EC-decay half-lives
of neutron-deficient Ar, Ca, Ti, Fe, Ni, Zn, Cd, and Sn isotopes. The isoscalar
proton-neutron pairing is found to play an important role in reducing the decay
half-lives, which is consistent with the same mechanism in the decays
of neutron-rich nuclei. The experimental /EC-decay half-lives can be
well reproduced by a universal isoscalar proton-neutron pairing strength.Comment: 12 pages, 4 figure
-decay half-lives of neutron-rich nuclei and matter flow in the -process
The -decay half-lives of neutron-rich nuclei with are systematically investigated using the newly developed fully
self-consistent proton-neutron quasiparticle random phase approximation (QRPA),
based on the spherical relativistic Hartree-Fock-Bogoliubov (RHFB) framework.
Available data are reproduced by including an isospin-dependent proton-neutron
pairing interaction in the isoscalar channel of the RHFB+QRPA model. With the
calculated -decay half-lives of neutron-rich nuclei a remarkable
speeding up of -matter flow is predicted. This leads to enhanced -process
abundances of elements with , an important result for the
understanding of the origin of heavy elements in the universe.Comment: 14 pages, 4 figure
Optical Control of Topological Quantum Transport in Semiconductors
Intense coherent laser radiation red-detuned from absorption edge can
reactively activate sizable Hall type charge and spin transport in n-doped
paramagnetic semiconductors as a consequence of k-space Berry curvature
transferred from valence band to photon-dressed conduction band. In the
presence of disorder, the optically induced Hall conductance can change sign
with laser intensity.Comment: to appear in Phys. Rev. Let
Compression of Atomic Phase Space Using an Asymmetric One-Way Barrier
We show how to construct asymmetric optical barriers for atoms. These
barriers can be used to compress phase space of a sample by creating a confined
region in space where atoms can accumulate with heating at the single photon
recoil level. We illustrate our method with a simple two-level model and then
show how it can be applied to more realistic multi-level atoms
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