Physical Warp Drives (2021)
I always find these kind of papers interesting. It seems like they found a more general &quot;warp drive&quot; metric. But after skimming it, I don&#x27;t understand how they want to create it in reality.<p>The best shot I think we have at metric engineering - unless you want to build something crazy like moving spheres and rings of ultra dense matter - is to look into materials with interesting spin-gravity coupling.<p>We know that rotating bodies have additional gravitational interactions. The effect is tiny, but measurable in experiments (e.g. Gravity Probe B). We also know that atomic spin is not just an abstract quantum number but actual angular momentum. So there should be some kind of spin-gravity interaction, even though it would be incredibly weak. But even though the absolute force is small, if we manage to make it <i>time dependent</i> we could amplify the effect. Just like a changing magetic field creates an electric field, a changing &quot;gravitomagnetic&quot; field would create a gravitational field. This is basically the insight that took us from compasses and static electricity to the whole of electrical engineering.<p>I am not sure such materials could even exist. And even though I have a PhD in Physics, I have no idea how one would approach this theoretically. The treatment of particle spin seems to be very rare in GR, and then you would have to marry this to solid state physics and somehow calculate how the situation changes when the spin density changes and so on... The furthest I got was to open a thread on stackexchange about it :-) but who knows, maybe someday somebody looks into this stuff:<p><a href="https:&#x2F;&#x2F;physics.stackexchange.com&#x2F;questions&#x2F;46099&#x2F;materials-with-different-gravitomagnetic-permeability" rel="nofollow">https:&#x2F;&#x2F;physics.stackexchange.com&#x2F;questions&#x2F;46099&#x2F;materials-...</a>