Information in the Holographic Universe:
A Holographic Spacetime By Jacob D. Bekenstein
TWO UNIVERSES of different dimension and obeying disparate physical laws are rendered completely equivalent by the holographic principle. Theorists have demonstrated this principle mathematically for a specific type of fivedimensional spacetime ("anti–de Sitter") and its fourdimensional boundary. In effect, the 5D universe is recorded like a hologram on the 4D surface at its periphery. Superstring theory rules in the 5D spacetime, but a socalled conformal field theory of point particles operates on the 4D hologram. A black hole in the 5D spacetime is equivalent to hot radiation on the hologramfor example, the hole and the radiation have the same entropy even though the physical origin of the entropy is completely different for each case. Although these two descriptions of the universe seem utterly unalike, no experiment could distinguish between them, even in principle.
