arXiv subjects

Hiroko Ichie

Publications and source records attributed to Hiroko Ichie.

28 records · Page 2Linked to original sources

arXiv1997

The Critical Scale of the Dual Superconductor Picture of QCD

The nonperturbative phenomena of QCD like color confinement is well described through the dual superconductor picture in the Maximally Abelian (MA) gauge. In this gauge, monopoles appear as important degrees of freedom composed by nonabelian gauge fields. We investigate the peculiar size $R_c$ of the monopole in the MA gauge, considering the theoretical similarity between spinglass and the MA gauge fixing. As for the properties at larger scale than the monopole size $R_c$, the system can be described by the dual superconductor theory with local abelian fields. At shorter distances than $R_c$, such a dual Higgs theory should be treated as a non-local field theory, and therefore one must take another framework like the perturbative QCD. Thus, the monopole size gives a critical scale on the change of the theoretical structure of QCD.

hep-lat↗

arXiv1997

Monopole Current Dynamics and Color Confinement

Color confinement can be understood by the dual Higgs theory, where monopole condensation leads to the exclusion of the electric flux from the QCD vacuum. We study the role of the monopole for color confinement by investigating the monopole current system. When the self-energy of the monopole current is small enough, long and complicated monopole world-lines appear, which is a signal of monopole condensation. In the dense monopole system, the Wilson loop obeys the area-law, and the string tension and the monopole density have similar behavior as the function of the self-energy, which seems that monopole condensation leads to color confinement. On the long-distance physics, the monopole current system almost reproduces essential features of confinement properties in lattice QCD. In the short-distance physics, however, the monopole-current theory would become nonlocal and complicated due to the monopole size effect. This monopole size would provide a critical scale of QCD in terms of the dual Higgs mechanism.

hep-lat↗

arXiv1996

QCD Phase Transition at high Temperature in Cosmology

The cosmological QCD phase transition is studied in terms of the color confinement at finite temperature using the dual Higgs theory of QCD. The confinement force is largely reduced at high temperature, which leads to the swelling of hadrons. We derive analytical formulae for the surface tension and the boundary thickness of the mixed phase from the effective potential at $T_c$. We predict a large reduction of the glueball mass near $T_c$. We investigate also the process of the hadron-bubble formation in the early Universe.

hep-ph↗

arXiv1996

Dual Higgs Mechanism and Nonperturbative QCD

We study the dual Higgs mechanism for the nonperturbative QCD. We point out two kind of the ``see-saw'' relations between electric and magnetic sectors. Owing to the Dirac condition $eg=4π$, the dual Ginzburg-Landau theory has the asymptotic freedom nature on the gauge coupling constant $e$, where the ``walking coupling constant'' is predicted for $e$ in the infrared region. We study also QCD-monopoles and instantons, which are two relevant topological objects in QCD. Strong correlations between the QCD-monopole trajectory and the topological charge are found both in the continuum theory and in the lattice gauge theory.

hep-ph↗

arXiv1996

Recent Progress in Nonperturbative QCD Theory and Insight on Cosmological Phase Transition

The QCD phase transition at finite temperature is studied with the dual Ginzburg-Landau theory, which is the QCD effective theory based on the dual Higgs mechanism by QCD-monopole condensation. At high temperature, the confinement force is largely reduced by thermal effects, which leads to the swelling of hadrons. Simple formulae for the surface tension and the thickness of the phase boundary are derived from the shape of the effective potential at the critical temperature. We investigate also the process of the hadron-bubble formation in the early Universe.

hep-ph↗

arXiv1996

Chiral Symmetry Breaking in the Dual Ginzburg-Landau Theory

Confinement and chiral symmetry breaking are the most fundamental phenomena in Quark Nuclear Physics, where hadrons and nuclei are described in terms of quarks and gluons. The dual Ginzburg-Landau (DGL) theory, which contains monopole fields as the most essential degrees of freedom and their condensation in the vacuum, is modeled to describe quark confinement in strong connection with QCD. We then demonstrate that the DGL theory is able to describe the spontaneous break down of the chiral symmetry.

hep-ph↗

arXiv1995

Dual Ginzburg-Landau Theory for Quark Confinement and Dynamical Chiral-Symmetry Breaking

Nonperturbative features of QCD are studied using the dual Ginzburg-Landau (DGL) theory with QCD-monopoles. The linear quark potential appears in the QCD-monopole condensed vacuum. We find that QCD-monopole condensation plays an essential role to the dynamical chiral-symmetry breaking. We also investigate the QCD phase transition at finite temperature in the DGL theory.

hep-ph↗

arXiv1995

QCD Phase Transition at Finite Temperature in the Dual Ginzburg-Landau Theory

We study the pure-gauge QCD phase transition at finite temperatures in the dual Ginzburg-Landau theory, an effective theory of QCD based on the dual Higgs mechanism. We formulate the effective potential at various temperatures by introducing the quadratic source term, which is a new useful method to obtain the effective potential in the negative-curvature region. Thermal effects reduce the QCD-monopole condensate and bring a first-order deconfinement phase transition. We find a large reduction of the self-interaction among QCD-monopoles and the glueball masses near the critical temperature by considering the temperature dependence of the self-interaction. We also calculate the string tension at finite temperatures.

hep-ph↗

arXiv1995

Dual Higgs Mechanism for Quarks in Hadrons

We study nonperturbative features of QCD using the dual Ginzburg-Landau (DGL) theory, where the color confinement is realized through the dual Higgs mechanism brought by QCD-monopole condensation. The linear confinement potential appears in the QCD-monopole condensed vacuum. We study the infrared screening effect to the confinement potential by the light-quark pair creation, and derive a compact formula for the screened quark potential. We study the dynamical chiral-symmetry breaking (D$χ$SB) in the DGL theory by solving the Schwinger-Dyson equation. QCD-monopole condensation plays an essential role to D$χ$SB. The QCD phase transition at finite temperature is studied using the effective potential formalism in the DGL theory. We find the reduction of QCD-monopole condensation and the string tension at high temperatures. The surface tension is calculated using the effective potential at the critical temperature. The DGL theory predicts a large mass reduction of glueballs near the critical temperature. We apply the DGL theory to the quark-gluon-plasma (QGP) physics in the ultrarelativistic heavy-ion collisions. We propose a new scenario of the QGP formation via the annihilation of color-electric flux tubes based on the attractive force between them.

hep-ph↗

arXiv1993

Effective Masses and Sizes of N(939), $Δ\!\!\mbox{\boldmath(1232)}$ and N(1440) in Nuclear Medium

The effective masses and sizes of N(939), $Δ(1232)$ and N(1440) in nuclear medium are calculated for a model in which quarks are subjected to a confinement force quenched by the scalar part of nuclear interactions. At the nuclear matter density, the nucleon swells by 50\% relative to the free nucleon. The masses of $Δ(1232)$ and N(1440) decrease in nuclear medium more than the nucleon, so that the pion requires less energy to excite them in nuclear medium than it does for a free nucleon.

nucl-th↗