While true invisibility cloaks may remain forever a dream, the ability to vanish into an ethereal ray of light is still on the cards.
A device that bends microwaves around an object has been shown to render it
partially invisible (New Scientist, 28 October 2006, p 29), but Min Qiu of the Royal Institute of Technology in Kista, Sweden, and colleagues argue that total invisibility would require the value of some of the cloak's key electrical and magnetic properties to be infinitely large - something that is impossible.
A more realistic goal is to remove the part of the cloak where the values should be infinitely large. They have calculated that the resulting cloak renders someone entirely invisible and
leaves only a thin line of light in the object's place. The results will be published in Physical Review Letters.
