Just re-reading The Forever War at the moment, so this seems very apropos. io9 looks into the recent possible breakthrough on a functioning warp drive. “Mathematically, the field equations predict that this is possible, but it remains to be seen if we could ever reduce this to practice.“
Of course, while mathematicians might have gotten around the “ridiculous amounts of energy required” problem, there’s now the new issue of ridiculous amounts of energy expended — in a lethal frontward cone. “When the Alcubierre-driven ship decelerates from superluminal speed, the particles its bubble has gathered are released in energetic outbursts. In the case of forward-facing particles the outburst can be very energetic — enough to destroy anyone at the destination directly in front of the ship. ‘Any people at the destination,’ the team’s paper concludes, ‘would be gamma ray and high energy particle blasted into oblivion due to the extreme blueshifts for [forward] region particles.'”