Color Ferromagnetism of Quark Matter ; a Possible Origin of Strong Magnetic Field in Magnetars

We show a possibility that strong ``magnetic field'' $\sim 10^{15}$G is produced by color ferromagnetic quark matter in neutron stars. In the quark matter a color magnetic field is generated spontaneously owing to Savvidy mechanism and a gluon condensate arises for the stabilization of the field. Since the quark matter is electrically charged in the neutron stars, the rotation of the quarks around the color magnetic field produces the strong ``magnetic field''.Comment: 7 page

Quark Pair Production in Expanding Glasma

Glasma in high energy heavy ion collisions is longitudinal classical color electric and magnetic fields. The color electric field has been shown to produces quark and anti-quark pairs by the Schwinger mechanism and to oscillate with time in non-expanding glasma, that is, plasma oscillation. On the other hand, in the expanding glasma we show that the field decreases with the plasma oscillation. We can explicitly obtain the solutions representing such temporal behaviors in the system with $\tau$ and $\eta$ coordinates. We show these results by using massless QED as a simplified model of QCD.Comment: 8 pages, 2 figure