The Alcubierre drive requires a region of space with negative energy density; we don’t know any way to produce this, but if there is it would involve some currently-unknown form of matter (which is referred to as “exotic matter”, which is just a catch-all label, not something specific).
I’ve read and been told that this is not entirely accurate; apparently, tiny pockets with effectively this effect have been created in labs by abusing things I don’t understand.
However, it’s apparently still under question whether these can be aggregated and scaled up at all, or if they are isolated events that can only be made under specific one-off circumstances.
I’ve read and been told that this is not entirely accurate; apparently, tiny pockets with effectively this effect have been created in labs by abusing things I don’t understand.
However, it’s apparently still under question whether these can be aggregated and scaled up at all, or if they are isolated events that can only be made under specific one-off circumstances.