From Destinypedia, the Destiny wiki
Vex Sol Collective
Light Support Patrol Unit
Vex Laser Rifle Harpy Slap Rifle
High Durability Rapid Flight Midair Levitation Alter Stance Arc Shield (Heroic)
Quantum Harpies are a stronger Elite variant of the Harpy seen throughout Vex controlled space. They can be distinguished from their Minor counterparts by their more silvery appearance.