I'm not qualified to speak to the science behind this drive but I can mention something about the mathematics it (supposedly) violates. The conservation of momentum is a mathematical model, and one that so far everything appears to follow, much like Euclidean geometry, which held right up until we discovered relativity. However unlike Euclidean geometry or Newtonian physics, which the conservation of momentum is implied within, momentum is still conserved (in a generalised, linear sense) in quantum mechanics and general relativity.
Which means one of two things must be the case, either the model no longer applies in this instance, or this does not actually have a closed system the most theorists would assume (this is touched with "it could have something to do with the technology manipulating subatomic particles which constantly pop in and out of existence in empty space." but that is when I'm afraid I must defer to someone with a better understanding of subatomic particles than me)