This is an abstract of an article behind a paywall so we can't see this details but it is from 2021 and I managed to find an article discussing the concept [1]

This is an abstract of an article behind a paywall so we can't see this details but it is from 2021 and I managed to find an article discussing the concept [1] > In this case negative energy is not required — rather it’s gravity itself which bends spacetime and gives rise to time dilation. In essence the gravitational field makes the passage of time within the passenger area much slower than the passage of time outside of it. A few minutes for them may be thousands of years worth of space travel, yet to leverage this powerful effect would take enormous amounts of gravity. The paper calls for the compression of an entire planet down to just a thin shell surrounding the passengers. The introduction of a physical warp drive model has changed the question from “Does something like negative energy even exist?” to “How do we compress the mass of a planet down to the size of a spaceship?” And I'll pull out the most apropos sentence: > The paper calls for the compression of an entire planet down to just a thin shell surrounding the passengers Yes, no negative energy or negative energy mass, just an entire planet compressed into a thin shell that somehow doesn't further collapse. So even if this were possible, how would you accelerate or maneuver such a massive object? I've seen so many of these proposals over the years. It's all nuclear-grade hopium with a massive flaw or huge, highly theoretical unknown. Always. [1]: https://medium.com/predict/the-first-physical-warp-drive-models-921055800764 https://medium.com/predict/the-first-physical-warp-drive-mod...