Antimatter and Phase Jumping:
Phase jumping does not cost antimatter. The act of jumping has a negative effect on antimatter that renders portions of it unuseable effectively consuming it. Thus, a ship without any antimatter reserves can still make a jump.
Blair
So far as I know, that is all the information we have available on the subject.
My take on it is that it is a defense against being unable to jump due to low AM but still preventing you from jumping around like a kangaroo all hopped up on speed.
On your way IN the effect would be pretty much the same as if it was just consumed: there is a portion of the AM that you cannot use for a period of time. The rate at which it become usable again is unknown. It could be the same as normal recharge or it could be slower or even faster for all we know. I seriously doubt that that it is permanent because that would encourage camping strategies.
On the way OUT, however, it makes a
huge difference because now no matter how depleted your AM is from a battle you can still make a jump. That could be the difference between losing your entire fleet in a lost battle and making a successful retreat and live to fight another day.
I think that it will be represented as a grayed-out (or some equivalent) area at the beginning or end of your antimatter bar that recharges/become available again at a different rate than antimatter that has been used in the conventional sense.
Anyone else feel like taking a crack at reverse-engineering the whole system from 3 short sentences?