An advanced intelligence wouldn't even dream of building Alcubierre drives and wormhole generators until they had mastered Dyson spheres. Short of intercepting designed radio signals, detecting this type of civilization is among the best bets we've got for discovering E.T. Click here for the official site for the search of Dyson spheres.
Discovery has a summary in plainer English.
Speaking of Alcubierre drives, io9 has a good article for why they just won't work, but could theoretically make a hell of a weapon.
Do you think an Alcubierre drive would work? Let's hear what you have to say in the comments below.