I thought that particle generation conserves momentum? For that purpose the vacuum needs to be polarized and the particle must in average be expelled/ produced to fly opposite the thrust (in line with movement) direction...
Wasn't the theory originally about massless propulsion?
I suppose particle generation would conserve momentum. Generate particles from an equal amount of energy, and send them out of one end of the drive. But (1) that's not massless propulsion; it's mass-full propulsion. It's definitely not propellent-less propulsion. (2) I don't think it is what Zephyr_AWT was proposing. (3) I don't think it's what Shawyer is proposing. And (4) where do the keV and GeV to create particles come from?