A wormhole for magnets has been created by scientists in a laboratory. The wormhole is not of the space-time variety, but rather it tunnels a magnetic field from one point to another.
The researchers, from the Autonomous University of Barcelona in Spain, published their findings in the journal Scientific Reports."Wormholes are fascinating cosmological objects that can connect two distant regions of the universe. Because of their intriguing nature, constructing a wormhole in a lab seems a formidable task," they wrote.
Their study was based on a theoretical proposal that would result in a wormhole for electromagnetic waves – allowing propagation between two points through an "invisible tunnel". "However, an actual realisation has not been possible until now." The scientists built a device that works as a wormhole in that if it is put inside a magnetic field, it is undetectable. As well as this, if another magnetic field travels through it, it looks like it has left space completely, appearing only at either end of the wormhole:
"Although inspired by the theoretical proposal of Greenleaf et al, we do not design our wormhole based on transformation optics," they wrote. "Instead, we take advantage of the possibilities that magnetic metamaterials offer for shaping static magnetic fields." The device is a sphere with three layers. In the middle is a magnetised metal tube which is then surrounded by a sphere made of strips of a superconducting material. The final sphere was placed over this.
"Using magnetic metamaterials and metasurfaces, our wormhole transfers the magnetic field from one point in space to another through a path that is magnetically undetectable," the authors said. "We experimentally show that the magnetic field from a source at one end of the wormhole appears at the other end as an isolated magnetic monopolar field, creating the illusion of a magnetic field propagating through a tunnel outside the 3D space."
In terms of practical application, the scientists say it could be the basis for a new type of MRI machine that would mean patients did not have to sit inside while being examined: "One particularly relevant application along this line could be in magnetic resonance imaging. Using the ideas in this work, one could foresee ways to apply a magnetic field locally to a patient, without distorting the homogenous magnetic field in the region. They could be useful, for example, in medical operations using simultaneous MRI imaging."