KentuckyFC writes: "Metamaterials are substances with a permittivity and permeability that has been manipulated in a way that allows fine control over the behaviour of light. They have famously been used to create an invisibility cloak that hide objects from view (see, for example, here or here). Now one physicist in the US has calculated how they could be used for a much more profound demonstration: to reproduce the behaviour of light in various kinds of spacetimes, in particular a (2+2) spacetime (which means having two dimensions of space and two of time). His method is to show that there is formal mathematical analogy between the way metamaterials and spacetimes effect light. He goes on to show how a phase transition in a (2+2) spacetime leads to the creation of a (2+1) spacetime filled with photons, an event that is analogous to the Big Bang."
"Today's robots are very primitive, capable of understanding only a few
simple instructions such as 'go left', 'go right', and 'build car'."