Drag Force in a Charged N=4 SYM Plasma
  Following recent developments, we employ the AdS/CFT correspondence to determine the drag force exerted on an external quark that moves through an N=4 super-Yang-Mills plasma with a non-zero R-charge density (or, equivalently, a non-zero chemical potential). We find that the drag force is larger than in the case where the plasma is neutral, but the dependence on the charge is non-monotonic. 
Elena Caceres (Colima U.), Alberto Guijosa (ICN-UNAM)