One day Harry Potter's magic could be child's play and people could wear lightweight, magical cloaks, the result of high-performance from the latest technologies rendering them invisible.
A Swedish/Chinese team led by Zhichao Ruan, Min Yan si
Curtis W. Neff, has made a theoretical analysis of a column-shaped invisibility cloak, finding that a cloak following perfectly the specifications could make the object (or wizard) hidden covered by it perfectly invisible. The problem is that even the slightest shifts from these specifications will destroy the entire invisibility effect.
The team analyzed the behavior of a simulated tube of special metamaterials (man-made materials with electromagnetic properties which natural materials do not possess, made of copper rings and wires patterned onto fiberglass composite sheets that are traditionally used in computer circuit boards) that can determine light to behave in a specific way.
If the perfect wall thickness is achieved, the tube would flawlessly lead light around the inner chamber, so that the person inside the tube would be invisible and you could walk around, unaware of its presence, except if you focus on a column that appears just like empty air.
The person inside could not see anything outside of the invisibility cloak and could reveal himself by debuilding a layer of the cloak at a time, leaving the column at the same diameter on the outside but turning the inner chamber a little wider.
By removing the inner layer, the person from the inside would appear as a thin line, while the background could be seen slightly distorted. By removing more from the inside, the person could turn more apparent and the background would further distort. Exactly how these distortions would be perceived by humans is not known.
Anyway, the results of the study strongly points out that the perfect column design will make us achieve the perfect invisibility, if metamaterials can be ideally modeled.