I've read a bit on Harold White's recent work. (A paper on Nasa's site) I haven't been able to find any comments by people claiming to know anything about the physics involved. Is this really serious? From a blog post (first link in this question):
"But interesting things have developed since the original Alcubierre paper. Running quickly through what White told the Houston audience, Chris van Den Broeck was able to reduce the energy costs of a warp drive significantly and other theorists have continued to drop the numbers. White’s team has been examining ways to continue that progression, but what is eye-catching is that he is working on a laboratory experiment to “perturb spacetime by one part in ten million” using an instrument called the White-Juday Warp Field Interferometer to create the minute spacetime disruption. "