595 research outputs found
Skyrmions, Hadrons and isospin chemical potential
Using the Hamiltonian formulation, in terms of collective variables, we
explore the evolution of different skyrmionic parameters as function of the
isospin chemical potential (), such as the energy density, the charge
density, the isoscalar radius and the isoscalar magnetic radius. We found that
the radii start to grow very fast for MeV, suggesting the
occurrence of a phase transition.Comment: 10 pages, 5 figure
Skyrme model and Isospin Chemical Potential
We discuss the stability of the Skyrmion solution in the presence of a finite
isospin chemical potential . Solving numerically the mass of the Skyrmion
as function of , we find a critical value MeV where the
Skyrmion mass vanishes. We compare the exact numerical treatment with an
analytical discussion based on a special shape for the profile of the Skyrmion
due to Atiyah and Manton. The extension of this ansatz for finite works
quite well for MeV. Then, for small values of , where the
analytical approach is valid, we consider the possibility of having an angular
deformation for the Skyrmionic profile, which is possible for finite values of
. This is however, a small effect. Finally we introduce finite temperature
corrections, which strength the instability induced by the chemical potential,
finding the dependence of the critical temperature on .Comment: 13 pages, 7 figure
Image-potential band-gap narrowing at a metal/semiconductor interface
GW approximation is used to systematically revisit the image-potential
band-gap narrowing at metal/semiconductor interfaces proposed by Inkson in the
1970's. Here we have questioned how the narrowing as calculated from
quasi-particle energy spectra for the jellium/Si interface depends on of
the jellium. The gap narrowing is found to only weakly depend on (i.e.,
narrowing eV even for a large . Hence we can turn to
smaller polarizability in the semiconductor side as an important factor in
looking for larger narrowing.Comment: 6 pages, 7 figure
Background field method at finite temperature and density
In this letter we make use of the Background Field Method (BFM) to compute
the effective potential of an SU(2) gauge field theory, in the presence of
chemical potential and temperature. The main idea is to consider the chemical
potential as the background field. The gauge fixing condition required by the
BFM turns out to be exactly the one we found in a previous article in a
different context.Comment: 6 pages, no figure
Weinberg-Salam model at finite temperature and density
We present a new gauge fixing condition for the Weinberg-Salam electro-weak
theory at finite temperature and density.
After spontaneous symmetry breaking occurs, every unphysical term in the
Lagrangian is eliminated with our gauge fixing condition. A new and simple
Lagrangian can be obtained where we can identify the propagators and vertices.
Some consequences are discussed, as the new gauge dependent masses of the gauge
fields and the new Faddeev-Popov Lagrangian. After obtaining the quadratic
terms, we calculate exactly the 1-loop effective potential identifying the
contribution of every particular field.Comment: 4 pages, no figures. New references added. Typo correcte
Variational Study of the Phase Transition at Finite T in the -Theory
Assuming triviality of the 4-dimensional -theory we compute
the effective potential by means of a self consistent Feynman-Bogoliubov
method. This potential depends on a UV-cutoff, which is fixed by
a stability condition for the gap-equation for the plasma mass. It shows a
second order phase transition at zero temperature, in agreement with a large
amount of analytical and RG analysis as well as Monte Carlo numerical evidence.
As the cutoff is removed the renormalized self coupling constant
goes to zero consistent with the claim of triviality. At finite
temperature the phase transition becomes weakly first order.Comment: 8 pages, latex, 4 figures available from author e-mail:
[email protected], submitted to Phys. Lett.
Association between physical fitness parameters and health related quality of life in Chilean community-dwelling older adults
Indexación: Web of Science; Scopus; Scielo.Background: There is no conclusive evidence about the association between physical fitness (PF) and health related quality of life (HRQOL) in older adults. Aim: To seek for an association between PF and HRQOL in non-disabled community- dwelling Chilean older adults. Material and Methods: One hundred and sixteen subjects participated in the study. PF was assessed using the Senior Fitness Test (SFT) and hand grip strength (HGS). HRQOL was assessed using eight dimensions provided by the SF-12v2 questionnaire. Binary multivariate logistic regression models were carried out considering the potential influence of confounder variables. Results: Non-adjusted models, indicated that subjects with better performance in arm curl test (ACT) were more likely to score higher on vitality dimension (OR > 1) and those with higher HGS were more likely to score higher on physical functioning, bodily pain, vitality and mental health (OR > 1). The adjusted models consistently showed that ACT and HGS predicted a favorable perception of vitality and mental health dimensions respectively (OR > 1). Conclusions: HGS and ACT have a predictive value for certain dimensions of HRQOL.http://ref.scielo.org/47dsj
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