6,429 research outputs found
Microscopic linear response calculations based on the Skyrme functional plus the pairing contribution
A self-consistent Quasiparticle-Random-Phase-Approximation (QRPA) model which
employs the canonical Hartree-Fock-Bogoliubov (HFB) basis and an energy-density
functional with a Skyrme mean field part and a density-dependent pairing, is
used to study the monopole collective excitations of spherical even-even
nuclei. The influence of the spurious state on the strength function of the
isoscalar monopole excitations is clearly assessed. We compare the effect of
different kinds of pairing forces (volume pairing, surface pairing and mixed
pairing) on the monopole excitation strength function. The energy of the
Isoscalar Giant Monopole Resonance (ISGMR), which is related to the nuclear
incompressibility , is calculated for tin isotopes and the results
are discussed.Comment: Accepted for publication in Phys. Rev.
Pairing Properties of Symmetric Nuclear Matter in Relativistic Mean Field Theory
The properties of pairing correlations in symmetric nuclear matter are
studied in the relativistic mean field (RMF) theory with the effective
interaction PK1. Considering well-known problem that the pairing gap at Fermi
surface calculated with RMF effective interactions are three times larger than
that with Gogny force, an effective factor in the particle-particle channel is
introduced. For the RMF calculation with PK1, an effective factor 0.76 give a
maximum pairing gap 3.2 MeV at Fermi momentum 0.9 fm, which are
consistent with the result with Gogny force.Comment: 14 pages, 6 figures
Generalized Debye Sources Based EFIE Solver on Subdivision Surfaces
The electric field integral equation is a well known workhorse for obtaining
fields scattered by a perfect electric conducting (PEC) object. As a result,
the nuances and challenges of solving this equation have been examined for a
while. Two recent papers motivate the effort presented in this paper. Unlike
traditional work that uses equivalent currents defined on surfaces, recent
research proposes a technique that results in well conditioned systems by
employing generalized Debye sources (GDS) as unknowns. In a complementary
effort, some of us developed a method that exploits the same representation for
both the geometry (subdivision surface representations) and functions defined
on the geometry, also known as isogeometric analysis (IGA). The challenge in
generalizing GDS method to a discretized geometry is the complexity of the
intermediate operators. However, thanks to our earlier work on subdivision
surfaces, the additional smoothness of geometric representation permits
discretizing these intermediate operations. In this paper, we employ both ideas
to present a well conditioned GDS-EFIE. Here, the intermediate surface
Laplacian is well discretized by using subdivision basis. Likewise, using
subdivision basis to represent the sources, results in an efficient and
accurate IGA framework. Numerous results are presented to demonstrate the
efficacy of the approach
Topological phase transition based on the attractive Hubbard model
We theoretically investigate the effect of an attractive on-site interaction
on the two-band magnetic Dirac fermion model based on a square lattice system.
When the attractive fermion interaction is taken into account by the mean-field
approximation, a phase diagram is obtained. It is found that a quantum phase
transition from a band insulator state to quantum anomalous Hall state occurs
with increased attractive interaction. For an existing quantum anomalous Hall
state, the attractive interaction enlarges its nontrivial band gap and makes
the topological edge states more localized, which protects the transport of
linear-dispersive edge states against finite-size and further disorder effects.Comment: 5 pages, 4 figure
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