Ideal invisibility cloaks like those in Harry Potter may be physically impossible, a new study shows. The researchers demonstrate that even the best invisibility cloaks can hide an object from only some observers, while other observers moving with respect to the first group would see distortions.
The physicists, Jad Halimeh at the Ludwig Maximilian University of Munich, Germany, and Robert Thompson at the University of Otago, New Zealand, have published a paper on the limitations of invisibility cloaks in a recent issue of Physical Review A.
As the researchers explain, limitations imposed by special relativity mean that the best invisibility cloaks would only be able to render objects partially transparent because they would suffer from obvious visible distortions due to motion. The result would be less Harry Potter and more like the translucent creatures in the 1987 movie Predator.
"In principle, what this paper shows is that invisibility cloaking is not possible for all observers," Halimeh told Phys.org. "Real invisibility cloaks will have to stay in the realm of fiction. Your cloak, if it is to be pragmatically broadband, will pretty much look like that of Predator, giving away what it hides via distortions when you move relative to it."
To read more, click here.