1,227 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
The continuum threshold and the Polyakov loop: A comparison between two deconfinement order parameters
We compare two order parameters for the deconfinement transition, induced by
thermal and density effects, commonly used in the literature, namely the
thermal and density evolution of the continuum threshold , within the
frame of the QCD sum rules, and the trace of the Polyakov loop in the
framework of a nonlocal chiral quark model. We include in our
discussion the evolution of the chiral quark condensate, the parameter that
characterizes the chiral symmetry restoration. We found that essentially both
order parameters, and , provide the same information for the
deconfinement transition, both for the zero and finite chemical potential
cases. At zero density, the critical temperatures in both cases coincide
exactly and, in the case of finite baryonic chemical potential , we find
evidence for the appearance of a quarkyonic phase.Comment: 6 pages, 1 table, 2 figures. Contribution to the proceedings of the
20th International Conference in Quantum Chromodynamics (QCD 17), 3 July - 7
July 2017, Montpellier, Franc
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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