901 research outputs found
Quantum Field Theories in Nonextensive Tsallis Statistics
Within the framework of Tsallis statistics with q ~ 1, we construct a
perturbation theory for treating relativistic quantum field systems. We find
that there appear initial correlations, which do not exist in the
Boltzmann-Gibbs statistics. Applying this framework to a quark-gluon plasma, we
find that the so-called thermal masses of quarks and gluons are smaller than in
the case of Boltzmann-Gibbs statistics.Comment: 16 pages, no figure
Ferromagnetism of two-flavor quark matter in chiral and/or color-superconducting phases at zero and finite temperatures
We study the phase structure of the unpolarized and polarized two-flavor
quark matters at zero and finite temperatures within the Nambu--Jona-Lasinio
(NJL) model. We focus on the region, which includes the coexisting phase of
quark-antiquark and diquark condensates. Generalizing the NJL model so as to
describe the polarized quark matter, we compute the thermodynamic potential as
a function of the quark chemical potential (), the temperature (), and
the polarization parameter. The result heavily depends on the ratio , where is the quark-antiquark coupling constant and is the
diquark coupling constant. We find that, for small , the
"ferromagnetic" phase is energetically favored over the "paramagnetic" phase.
On the other hand, for large , there appears the window in the
()-plane, in which the "paramagnetic" phase is favored.Comment: 25 pages, 10 figure
Nonet meson properties in Nambu--Jona-Lasinio model with dimensional versus cutoff regularization
Nambu--Jona-Lasinio (NJL) model with Kobayashi-Maskawa-'t Hooft (KMT) term is
one of low energy effective theory of QCD which includes the anomaly.
We investigate nonet meson properties in this model with three flavors of
quarks. We employ two type of regularizations the dimensional and sharp cutoff
ones. The model parameters are fixed phenomenologically for each
regularization. Evaluating the kaon decay constant, the meson mass and
the topological susceptibility, we show the regularization dependence of the
results and discuss the applicability of the NJL model.Comment: 11 pages, 9 figure
Cancellation of energy-divergences and renormalizability in Coulomb gauge QCD within the Lagrangian formalism
In Coulomb gauge QCD in the Lagrangian formalism, energy divergences arise in
individual diagrams. We give a proof on cancellation of these divergences to
all orders of perturbation theory without obstructing the algebraic
renormalizability of the theory.Comment: 13 pages, 7 figure
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