1,225 research outputs found
Two-flavor condensates in chiral dynamics: temperature and isospin density effects
Isospin density and thermal corrections for several condensates are
discussed, at the one-loop level, in the frame of chiral dynamics with pionic
degrees of freedom. The evolution of such objects give an additional insight
into the condensed-pion phase transition, that occurs basically when
|\mui|>m_\pi, being |\mui| the isospin chemical potential. Calculations are
done in both phases, showing a good agreement with lattice results for such
condensates.Comment: 9 pages, 10 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
Casimir energy for a scalar field with a frequency dependent boundary condition
We consider the vacuum energy for a scalar field subject to a frequency
dependent boundary condition. The effect of a frequency cut-off is described in
terms of an {\it incomplete} -function. The use of the Debye asymptotic
expansion for Bessel functions allows to determine the dominant (volume, area,
>...) terms in the Casimir energy. The possible interest of this kind of models
for dielectric media (and its application to sonoluminescence) is also
discussed.Comment: 7 pages, RevTeX. Version to appear in PRD (Introduction enlarged,
references added
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