Wormholes on Earth?

Nov 14, 2007 By Laura Mgrdichian feature

According to a group of mathematicians, it may be possible to create devices with internal tunnels that are invisible to detection by electromagnetic waves—wormholes, in a sense. The group discusses the idea in a paper published in the October 29 online edition of Physical Review Letters.

The scientists say that by custom designing the values of two parameters that describe electromagnetic (EM) materials, the electrical permittivity and magnetic permeability, around and inside a cylinder, a novel optical device could be produced. Essentially, most of the device would be invisible to detection by external EM radiation of a certain frequency, with only the ends of the cylinder being visible and accessible to the EM waves.

“The chosen values for the permittivity and permeability would cause the coating to manipulate EM waves in a way that is not seen in nature,” explained University of Rochester mathematician Allan Greenleaf, one of the paper's authors, to PhysOrg.com.

Permittivity is a measure of a material's readiness to become electrically polarized in response to an applied electric field (how well it “permits” the field). Permeability describes how magnetized a material becomes when a magnetic field is applied. Modern EM materials known as metamaterials allow theoretical designs, such as a wormhole, to be physically constructed, at least in principle.

Greenleaf and his colleagues, Yaroslav Kurylev of University College in London, Matti Lassas of the Helsinki University of Technology, and Gunther Uhlmann of the University of Washington, use the word “wormhole” in more of a mathematical sense than physical. That is, the devices would act as wormholes from the viewpoint of Maxwell's equations, the four fundamental equations that describe the relationship between electric fields, magnetic fields, electric charge, and electric current.

For any other frequencies than those for which the permittivity and permeability were designed, the tunnel region would look roughly like a solid cylinder. But for the right frequencies, says Greenleaf, “the tunnel has the effect of changing the topology of space. The electromagnetic waves behave as though they are propagating through a space to which a handle has been attached, in the same way that ants crawling on the door of your refrigerator have two ways to get from one end of the handle to the other: by traveling over the handle or on the flat surface underneath.”

That is, any object within the tunnel is only visible to EM waves that enter at one of the tunnel's ends. Conversely, any EM waves emitted by an object in the tunnel can only leave through one of the ends. However, Greenleaf says that it's important to note that the shape of space has not actually been changed, as does happen for Einstein-Rosen wormholes in general relativity.

This effect could have interesting applications. For example, a magnetic dipole (such as a bar magnet) placed near one of the ends would, at the other end, appear to approximate a magnetic monopole, a theoretical particle with only one magnetic pole, i.e. that has magnetic charge. True magnetic monopoles have never been discovered, and the work by Greenleaf and his colleagues does not claim otherwise.

The scientists propose other possible applications, such as in magnetic resonance imaging (MRI), where a wormhole device could be used to allow doctors to operate on a patient while simultaneously imaging the patient. Doctors could insert metal surgical tools into the tunnel area without disturbing the MRI machine's magnetic field.

Another example is an optical computer, where active components could be placed inside wormholes such as to not interact with each other and cause malfunctions.

Metamaterials for invisibility, while still in the very early stages of development, are already being researched. Last year, scientists from Duke University created a device that renders a copper disc invisible to observation by microwaves.

Citation: Allan Greenleaf, Yaroslav Kurylev, Matti Lassas, and Gunther Uhlmann “Electromagnetic Wormholes and Virtual Magnetic Monopoles from Metamaterials” Phys. Rev. Lett. 99, 183901 (2007)

Copyright 2007 PhysOrg.com.
All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of PhysOrg.com.

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User comments : 7

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flashgordon
3.7 / 5 (3) Nov 14, 2007
i think they should call this something else; clearly, these are not wormholes; they're just electromagnetic affects.
Patrick
3 / 5 (2) Nov 14, 2007
I created a "visible light" worm hole with an empty paper towel roll and a golf ball.... ha ha ha
LearmSceince
4.5 / 5 (2) Nov 14, 2007
Why have another story that just summarizes the old one?
C_Ell
5 / 5 (1) Nov 15, 2007
Why are they using the word wormhole? It's a cloaking device. Laypeople think of wormholes as links between two points in space. This is a cloaked tube.
Sean_W
2.6 / 5 (5) Nov 17, 2007
Usually I don't like nitpicking about poorly defined terminology but I must agree that the use of the term "wormhole" seems a very poor choice for what is, effectively, an invisible pipe. It might be a very useful technology if it can be made to work but the term "wormhole" is linked specifically to the concept of a "tunnel" through space time that is usually difficult to hit one's head on. How about just calling it a "Hogwarts pipe"?
gopher65
5 / 5 (1) Nov 18, 2007
Wormhole is such a general term that it is useless to use. Using it here is like writing a report on a species of interesting... I dunno... tree frog of some sort... from a rain forest and using the word "animal" everywhere in your report instead of the species name. It would be a useless and stupid thing to do.

Wormhole is just as general a word as Animal. Maybe moreso. More like saying Lifeform. That doesn't tell you much does it?

Not to mention that this is just a slightly reworded version of a story physorg.com ran a little while ago.
Mobius
1 / 5 (2) Dec 04, 2007
It was my understanding that an object placed in a "wormhole" Would exit on the other end before it was ever placed in the entrance
Anyone hear of this before???