Sadly not quite as cool as I was hoping. It's really a "push from the sides w/ the right angle against an appropriately shaped object such that net momentum is toward some putative 'source' of the beam when in fact there are two separate beams that are widely displaced from this 'source' location".

Definitely awesome, but I was so hoping for "...in a vacuum" with that one.

It already said "Acoustic"[0] ;)

0. = "Definitely not in a vacuum"

Right. So I see this comment mentioning tractor beam, I get my hopes up, and read "acoustic" in the article and come back here to express mild disappointment. Does the fact that I omitted that detail somehow mean I misunderstood?