For example, light travelling through a vacuum can be made to spontaneously form into an electron-positron pair–an entangled pair–which then recombine to form a photon again. How might such a machine work? Putz and Svozil point out that nonlocal phenomenon can lead to materials in which the index of refraction is less than one, thereby allowing superluminal speeds. They say there is no reason why not, provided the processing does not lead to any time travel paradoxes. So-called “nonlocal” phenomenon cannot be used to transmit information faster than the speed of light but Putz and Svozil today ask whether it can be used to process it, to carry out computational tasks at superluminal speeds. These particles can be separated by the diameter of the universe and yet a measurement on one will instantaneously influence the other. For example, the quantum phenomenon of entanglement occurs when two quantum particles are described by the same wave function. They say there are several ways that signals can cross the superluminal line, although none of them allow the kind of time travel paradoxes beloved of science fiction writers. Well, yes and no, say Volkmar Putz and Karl Svozil at the Vienna University of Technology in Austria. Nothing can travel faster than the speed of light, right? The speed of light represents one of the fundamental limits of the laws of physics.