Magnetic Wormhole

Magnetic wormhole created for first time

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Scientists in the Department of Physics at the Universitat Autònoma de Barcelona have designed and created in the laboratory the first experimental wormhole that can connect two regions of space magnetically. The device could have applications in medicine, opening up ways to make MRIs more comfortable for patients.

Experimental magnetic wormhole

“Wormholes” are cosmic tunnels that can connect two distant regions of the universe, and have been popularised by the dissemination of theoretical physics and by works of science fiction like Stargate, Star Trek or, more recently, Interstellar. Using present-day technology it would be impossible to create a gravitational wormhole, as the field would have to be manipulated with huge amounts of gravitational energy, which no-one yet knows how to generate. In electromagnetism, however, advances in metamaterials and invisibility have allowed researchers to put forward several designs to achieve this.

Scientists in the Department of Physics at the Universitat Autònoma de Barcelona have designed and created in the laboratory the first experimental wormhole that can connect two regions of space magnetically. This consists of a tunnel that transfers the magnetic field from one point to the other while keeping it undetectable – invisible – all the way.

The researchers used metamaterials and metasurfaces to build the tunnel experimentally, so that the magnetic field from a source, such as a magnet or a an electromagnet, appears at the other end of the wormhole as an isolated magnetic monopole. This result is strange enough in itself, as magnetic monopoles – magnets with only one pole, whether north or south – do not exist in nature. The overall effect is that of a magnetic field that appears to travel from one point to another through a dimension that lies outside the conventional three dimensions.

The wormhole in this experiment is a sphere made of different layers: an external layer with a ferromagnetic surface, a second inner layer, made of superconducting material, and a ferromagnetic sheet rolled into a cylinder that crosses the sphere from one end to the other. The sphere is made in such a way as to be magnetically undetectable – invisible, in magnetic field terms – from the exterior.

The magnetic wormhole is an analogy of gravitational ones, as it “changes the topology of space, as if the inner region has been magnetically erased from space”, explains Àlvar Sánchez, the lead researcher.

These same researchers had already built a magnetic fibre in 2014: a device capable of transporting the magnetic field from one end to the other. This fibre was, however, detectable magnetically. The wormhole developed now, though, is a completely three-dimensional device that is undetectable by any magnetic field.

This means a step forward towards possible applications in which magnetic fields are used: in medicine for example. This technology could, for example, increase patients’ comfort by distancing them from the detectors when having MRI scans in hospital, or allow MRI images of different parts of the body to be obtained simultaneously.

Magnetic Wormhole Created in Lab

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Ripped from the pages of a sci-fi novel, physicists have crafted a wormhole that tunnels a magnetic field through space.

“This device can transmit the magnetic field from one point in space to another point, through a path that is magnetically invisible,” said study co-author Jordi Prat-Camps, a doctoral candidate in physics at the Autonomous University of Barcelona in Spain. “From a magnetic point of view, this device acts like a wormhole, as if the magnetic field was transferred through an extra special dimension.”

The idea of a wormhole comes from Albert Einstein’s theories. In 1935, Einstein and colleague Nathan Rosen realized that the general theory of relativity allowed for the existence of bridges that could link two different points in space-time. Theoretically these Einstein-Rosen bridges, or wormholes, could allow something to tunnel instantly between great distances (though the tunnels in this theory are extremely tiny, so ordinarily wouldn’t fit a space traveler). So far, no one has found evidence that space-time wormholes actually exist. [Science Fact or Fiction? The Plausibility of 10 Sci-Fi Concepts]

The new wormhole isn’t a space-time wormhole per se, but is instead a realization of a futuristic “invisibility cloak” first proposed in 2007 in the journal Physical Review Letters. This type of wormhole would hide electromagnetic waves from view from the outside. The trouble was, to make the method work for light required materials that are extremely impractical and difficult to work with, Prat said.

Magnetic wormhole
But it turned out the materials to make a magnetic wormhole already exist and are much simpler to come by. In particular, superconductors, which can carry high levels of current, or charged particles, expel magnetic field lines from their interiors, essentially bending or distorting these lines. This essentially allows the magnetic field to do something different from its surrounding 3D environment, which is the first step in concealing the disturbance in a magnetic field.

So the team designed a three-layer object, consisting of two concentric spheres with an interior spiral-cylinder. The interior layer essentially transmitted a magnetic field from one end to the other, while the other two layers acted to conceal the field’s existence.

The inner cylinder was made of a ferromagnetic mu-metal. Ferromagnetic materials exhibit the strongest form of magnetism, while mu-metals are highly permeable and are often used for shielding electronic devices.

A thin shell made up of a high-temperature superconducting material called yttrium barium copper oxide lined the inner cylinder, bending the magnetic field that traveled through the interior.

Normally, magnetic field lines radiate out from a certain location and decay over time, but the presence of the magnetic field should be detectable from points all around it. However, the new magnetic wormhole funnels the magnetic field from one side of the cylinder to another so that it is “invisible” while in transit, seeming to pop out of nowhere on the exit side of the tube, the researchers report today (Aug. 20) in the journal Scientific Reports.

“From a magnetic point of view, you have the magnetic field from the magnet disappearing at one end of the wormhole and appearing again at the other end of the wormhole,” Prat told Live Science.

Broader applications
There’s no way to know if similar magnetic wormholes lurk in space, but the technology could have applications on Earth, Prat said. For instance, magnetic resonance imaging (MRI) machines use a giant magnet and require people to be in a tightly enclosed central tube for diagnostic imaging.

But if a device could funnel a magnetic field from one spot to the other, it would be possible to take pictures of the body with the strong magnet placed far away, freeing people from the claustrophobic environment of an MRI machine, Prat said.

To do that, the researchers would need to modify the shape of their magnetic wormhole device. A sphere is the simplest shape to model, but a cylindrical outer shell would be the most useful, Prat said.

“If you want to apply this to medical techniques or medical equipment, for sure you will be interested in directing toward any given direction,” Prat said. “A spherical shape is not the most practical geometry.”