Elliptic Flow from Color Glass Condensate
  We show that an observable fraction of the measured elliptic flow may originate in classical gluon fields at the initial stage of a peripheral high-energy nuclear collision. This mechanism complements the contribution of late stage mechanisms, such as those described by hydrodynamics, to the observed elliptic flow. 
Alex Krasnitz, Yasushi Nara, Raju Venugopalan