Magnetic susceptibility of quark matter within Fermi-liquid theory

Possibility of spontaneous magnetization in QCD and magnetic properties of quark matter is discussed by evaluating the magnetic susceptibility within Fermi-liquid theory. The screening effects for gluons are taken into account to figure out the specific properties of the magnetic transition in gauge theories. It is shown that the static screening effect in terms of the Debye mass does not necessarily work against the magnetic instability; it promotes the instability, depending on the coupling constant and the number of flavors.Comment: 10 pages, 2 figure

Delayed Collapse of Protoneutron Stars with Kaon Condensate

Equation of state with kaon condensate is derived for isentropic and neutrino-trapped matter. Both are important ingredients to study the delayed collapse of protoneutron stars. Solving the TOV equation, we discuss the static properties of protoneutron stars and implications for their delayed collapse.Comment: 6 pages, to appear in Proceedings of PANIC9

Protoneutron Stars with Kaon Condensation and their Delayed Collapse

Properties of protoneutron stars are discussed in the context of kaon condensation. Thermal and neutrino trapping effects are very important ingredients to study them. By solving the TOV equation, we discuss the static properties of protoneutron stars and the possibility of the delayed collapse during their evolution.Comment: 33pages,15 figures, accepted for publication in Nucl. Phys.

Magnetic aspects of QCD and compact stars

Magnetic properties of quark matter are discussed. The possibility of ferromagnetic transition is studied by using the one-gluon-exchange interaction. Magnetic susceptibility is evaluated within Landau Fermi liquid theory, and the important roles of the screening for the gluon propagation are elucidated. Static screening for the longitudinal gluons improves the infrared singularities, while the transverse gluons receive only dynamic screening. The latter property gives rise to a novel non-Fermi-liquid behaviour in the magnetic susceptibility. The critical density is estimated to be around the nuclear density and the Curie temperature several tens MeV. The spin density wave is also discussed at moderate densities, where chiral transition becomes important. Pseudoscalar condensate as well as scalar one takes a spatially non-uniform form in a chirally invariant way. Accordingly magnetization oscillates like spin density wave. These results should have some implications on compact star phenomena.Comment: 6 pages, 6 figures, Proc. of NFQCD10 to appear in Prog. Theor. Phys. Supp

Magnetic aspects of QCD at finite density and temperature

Some magnetic aspects of QCD are discussed at finite density and temperature. Possibility of spontaneous magnetization is studied within Landau Fermi-liquid theory, and the important roles of the screening effects for gluon propagation are elucidated. Static screening for the longitudinal gluons improves the infrared singularities, while the transverse gluons receive only dynamic screening. The latter property gives rise to a novel non-Fermi-liquid behaviour for the magnetic susceptibility. Appearance of a density-wave state is also discussed in relation to chiral transition, where pseudoscalar condensate as well as scalar one takes a spatially non-uniform form in a chirally invariant way. Accordingly magnetization of quark matter oscillates like spin density wave. A hadron-quark continuity is suggested in this aspect, remembering pion condensation in hadronic phase.Comment: 6 pages, 8 figures, Proc. of INPN2010 to appear in J. Phy

Pseudoscalar Mesons in Nuclear Medium

The behavior of pseudoscalar mesons in nuclear medium is reviewed with an emphasis on the possibility of their Bose-Einstein condensation in dense matter. In particular pion condensation is reexamined in detail, stimulated by recent theoretical and observational developments.Comment: Invited talk at the Workshop "MEDIUM02", Kyushu, Oct.25 - 26, 200

Microscopic origin of the magnetic field in compact stars

A magnetic aspect of quark matter is studied by the Fermi liquid theory. The magnetic susceptibility is derived with the one-gluon-exchange interaction, and the critical Fermi momentum for spontaneous spin polarization is found to be 1.4fm^{-1}. A scenario about the origin of the magnetic field in compact stars is presented by using this result.Comment: 6pages,2figure