Landau damping of gluons in the two-flavor color superconducting Fulde-Ferrell phase

We clarify aspects of gluon propagation in the two-flavor crystalline color superconducting phase of quark matter by analyzing the screening and Landau damping of gluons in the two-flavor Fulde-Ferrell (FF) phase. The paired quarks in the FF phase feature gapless excitations and therefore lead to Debye screening of the longitudinal t(1), t(2), and t(3) gluons and Landau damping of transverse t(1), t(2), and t(3) gluons. This is a marked difference from the 2SC phase where both of these are unscreened. The transverse t(1), t(2), and t(3) gluons are long ranged in the zero energy limit and hence the interaction mediated by these is the most important mechanism for the scattering of the paired quarks. Therefore they play an important role in determining their transport properties.