I’m not sure that’s correct. Every discussion I’ve seen regards it as a region of negative energy with respect to the normal vacuum, meaning it’s energy content is below that of the normal vacuum.
In any case, here’s an article on a different peer-reviewed published proposal for a warp drive, This one remarkably does not require negative energy:
Star Trek’s Warp Drive Leads to New Physics
Researchers are taking a closer look at this science-fiction staple—and bringing the idea a little closer to reality
By Robert Gast, Spektrum on July 13, 2021
https://www.scientificamerican.com/article/star-treks-warp-drive-leads-to-new-physics/
Robert Clark
