Metamaterial wormhole teleports magnetic fields across space

The trick could help us worm our way towards better scanners (Image: Monty Rakusen/Getty) It’s a new magician’s trick, sawing a magnetic field in half – and all you need is a wormhole. Magnetic fields entering it emerge at the other end as if teleported through space. The feat has practical applications too, such as improving MRI scans.

Despite its evocative name, the wormhole is no portal in space-time, but it does allow a magnetic field to disappear in one region and then re-emerge unchanged elsewhere. Alvaro Sanchez at the Autonomous University of Barcelona, Spain, and his colleagues were inspired to create one by a theoretical design originally proposed in 2007.

“They modified our earlier mathematical constructions in a very clever way so that an artificial wormhole could be built using present engineering techniques,” says Matti Lassas at the Helsinki University of Technology in Finland, who co-authored the earlier paper.
Sanchez’s team had transferred a magnetic field across space with a length of special tubing that acted as if it were a hose that could carry magnetic fields without them losing strength. But external magnetic fields would be able to distort the fields inside the hose. To look like a wormhole, the tube itself had to be made invisible.
“We needed to make a 3D magnetic cloak to hide the magnetic hose,” Sanchez says. To do that, they used metamaterials – artificial materials that interact in unusual ways with electromagnetic fields and that may some day be deployed to build invisibility cloaks for light.