Technology Review: Blogs: arXiv blog: How to Build a Warp Drive Using Metamaterials: "It turns out there is a formal mathematical analogy between the way metamaterials bend light and the way gravity does it. Inside metamaterials, electromagnetic space becomes distorted in exactly the same way as spacetime in general relatively.
That means physicists can use metamaterials to simulate the universe itself and all the weird phenomenon of general relativity. We've looked at various attempts to recreate black holes, the Big Bang and even multiverses.
But there's another thing that general relativity appears to allow: faster than light travel. In 1994, the Mexican physicist, Michael Alcubierre, realised that while relativity prevents faster-than-light travel relative to the fabric of spacetime, it places no restriction on the speed at which regions of spacetime can move relative to each other."