316 research outputs found
Recent Developments in the Skyrme Model
In this talk, we describe recent developments in the Skyrme model. Our main
focus is on discussing various effects which need to be taken into account,
when calculating the properties of light atomic nuclei in the Skyrme model. We
argue that an important step is to understand "spinning Skyrmions" and discuss
the theory of relative equilibria in this context.Comment: 9 pages, 1 figure. Talk given at 15th International Seminar on High
Energy Physics: Quarks - 2008, Sergiev Posad, Russia, 23-29 May 200
Dynamics of vortices with magnetic impurities
We investigate the dynamics of BPS vortices in the presence of magnetic impurities taking the form of axially-symmetric localised lumps and delta-functions. We present numerical results for vortices on flat space, as well as exact results for vortices on hyperbolic space in the presence of delta-function impurities. In fact, delta-function impurities of appropriate strength can be captured within the moduli space approximation by keeping one or more of the vortices fixed. We also show that previous work on vortices on the 2-sphere extends naturally to the inclusion of delta-function impurities
The Dimension of sustainable indicators for rehabilitation nursing care and its implications for people aged 65 and over with self-care deficit:Systematic Review of Literature
In the centrality of contemporary society, aging is one of the most worrying demographic phenomena with socioeconomic implications and has a profound impact on the design of social and sustainability policies and the field of
population health. Objective: Identify indicators sensitive to rehabilitation nursing care for people aged 65 and over
with self-care deficit. Method: Systematic literature review using EBSCO host database searches (MEDLINE,
CINAHL and MedicLatina), using the PI [C] O method. Results: The results sensitive to nursing care are observed
from the structured intervention of the same, as well as from their evaluation and registration, being mentioned the
increase: functional status, nutritional status, symptomatic control, safety, person satisfaction, health costs reduction,
management of the therapeutic regime and quality of life. Conclusion: Structured interventions of nursing care in
people aged 65 and over, related to the self-care deficit, have the variables mentioned above and reveal the need to
study the impact of rehabilitation nursing on self-care as a function of age, sex and literacy of people aged 65 or over,
in relation to: Activities of daily living; Body functions; Structure of the body; Participation activities and environmental
factors
Dynamics of multi-kinks in the presence of wells and barriers
Sine-Gordon kinks are a much studied integrable system that possesses
multi-soliton solutions. Recent studies on sine-Gordon kinks with
space-dependent square-well-type potentials have revealed interesting dynamics
of a single kink interacting with wells and barriers. In this paper, we study a
class of smooth space-dependent potentials and discuss the dynamics of one kink
in the presence of different wells. We also present values for the critical
velocity for different types of barriers. Furthermore, we study two kinks
interacting with various wells and describe interesting trajectories such as
double-trapping, kink knock-out and double-escape.Comment: 17 pages, 7 figure
Vortices and magnetic impurities
Ginzburg-Landau vortices in superconductors attract or repel depending on whether the value of the coupling constant λ is less than 1 or larger than 1. At critical coupling λ=1,it was previously observed that a strongly localised magnetic impurity behaves very similarly to a vortex. This remains true for axially symmetric configurations away from critical coupling. In particular, a delta function impurity of a suitable strength is related to a vortex configuration without impurity by singular gauge transformation. However, the interaction of vortices and impurities is more subtle and depends not only on the coupling constant λ and the impurity strength, but also on how broad the impurity is. Furthermore, the interaction typically depends on the distance and may be attractive at short distances and repulsive at long distances. Numerical simulations confirm moduli space approximation results for the scattering of one and two vortices with an impurity. However, a double vortex will split up when scattering with an impurity, and the direction of the split depends on the sign of the impurity. Head-on collisions of a single vortex with different impurities away from critical coupling is also briefly discussed
Fermions, Skyrmions and the 3-Sphere
This paper investigates a background charge one Skyrme field chirally coupled
to light fermions on the 3-sphere. The Dirac equation for the system commutes
with a generalised angular momentum or grand spin. It can be solved explicitly
for a Skyrme configuration given by the hedgehog form. The energy spectrum and
degeneracies are derived for all values of the grand spin. Solutions for
non-zero grand spin are each characterised by a set of four polynomials. The
paper also discusses the energy of the Dirac sea using zeta function
regularization.Comment: 19 pages, 2 figure
Baby Skyrme models without a potential term
We develop a one-parameter family of static baby Skyrme models that do not require a potential term to admit topological solitons. This is a novel property as the standard baby Skyrme model must contain a potential term in order to have stable soliton solutions, though the Skyrme model does not require this. Our new models satisfy an energy bound that is linear in terms of the topological charge and can be saturated in an extreme limit. They also satisfy a virial theorem that is shared by the Skyrme model. We calculate the solitons of our new models numerically and observe that their form depends significantly on the choice of parameter. In one extreme, we find compactons while at the other there is a scale invariant model in which solitons can be obtained exactly as solutions to a Bogomolny equation. We provide an initial investigation into these solitons and compare them with the baby Skyrmions of other models
Collective coordinates of the Skyrme model coupled with fermions
The problem of construction of fiber bundle over the moduli space of the
Skyrme model is considered. We analyse an extension of the original Skyrme
model which includes the minimal interaction with fermions. An analogy with
modili space of the fermion-monopole system is used to construct a fiber bundle
structure over the skyrmion moduli space. The possibility of the non-trivial
holonomy appearance is considered. It is shown that the effect of the fermion
interaction turns the -skyrmion moduli space into a real vector bundle with
natural connection.Comment: 10 page
Quantum lump dynamics on the two-sphere
It is well known that the low-energy classical dynamics of solitons of
Bogomol'nyi type is well approximated by geodesic motion in M_n, the moduli
space of static n-solitons. There is an obvious quantization of this dynamics
wherein the wavefunction evolves according to the Hamiltonian H_0 equal to
(half) the Laplacian on M_n. Born-Oppenheimer reduction of analogous mechanical
systems suggests, however, that this simple Hamiltonian should receive
corrections including k, the scalar curvature of M_n, and C, the n-soliton
Casimir energy, which are usually difficult to compute, and whose effect on the
energy spectrum is unknown. This paper analyzes the spectra of H_0 and two
corrections to it suggested by work of Moss and Shiiki, namely H_1=H_0+k/4 and
H_2=H_1+C, in the simple but nontrivial case of a single CP^1 lump moving on
the two-sphere. Here M_1=TSO(3), a noncompact kaehler 6-manifold invariant
under an SO(3)xSO(3) action, whose geometry is well understood. The symmetry
gives rise to two conserved angular momenta, spin and isospin. A hidden
isometry of M_1 is found which implies that all three energy spectra are
symmetric under spin-isospin interchange. The Casimir energy is found exactly
on the zero section of TSO(3), and approximated numerically on the rest of M_1.
The lowest 19 eigenvalues of H_i are found for i=0,1,2, and their spin-isospin
and parity compared. The curvature corrections in H_1 lead to a qualitatively
unchanged low-level spectrum while the Casimir energy in H_2 leads to
significant changes. The scaling behaviour of the spectra under changes in the
radii of the domain and target spheres is analyzed, and it is found that the
disparity between the spectra of H_1 and H_2 is reduced when the target sphere
is made smaller.Comment: 35 pages, 3 figure
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