Cloaking Devices, Electromagnetic Wormholes, and ......

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PhysOrg article....

SciAm Journals link....(PDF)

Abstract:

Cloaking Devices, Electromagnetic Wormholes, and Transformation Optics

We describe recent theoretical and experimental progress on making objects invisible to detection by electromagnetic waves. Ideas for devices that would once have seemed fanciful may now be at least approximately implemented physically using a new class of artificially structured materials called metamaterials. Maxwell's equations have transformation laws that allow for the design of electromagnetic material parameters that steer light around a hidden region, returning it to its original path on the far side. Not only would observers be unaware of the contents of the hidden region, they would not even be aware that something was being hidden. An object contained in the hidden region, which would have no shadow, is said to be cloaked. Proposals for, and even experimental implementations of, such cloaking devices have received the most attention, but other designs having striking effects on wave propagation are possible. All of these designs are initially based on the transformation laws of the equations that govern wave propagation but, due to the singular parameters that give rise to the desired effects, care needs to be taken in formulating and analyzing physically meaningful solutions. We recount the recent history of the subject and discuss some of the mathematical and physical issues involved.

 

[a_lost_packet_]

Thanks!

I especially enjoyed the end of the paper where other ideas were discussed using metamaterials and cloaking strategies. The "Perfect Lens" possible?

A general question:

Is all "information" physical?

IOW, information is the bread and butter of the universe. Everything has it to one degree or another. It's "detectable." In cases like EM "information" , it's even malleable. It's a physical Universe we live in therefore information is "physical" as well, right? In that light, "information" really is what we determine it is. Where it is conceptual, like our symbolic representation of the coordinates of an object x,y,z it really has no great meaning to the functioning of the universe in that form. But, there is obviously some form of "information" exchange through physical processes, in some cases imagined as stretching into other dimensions.

So, with that outlook, what about constructing a metamaterial that is invisible to the physical laws and "information exchange" of the Universe? Firstly, would it exist and, if so, would it matter or not? If you could construct such a thing out of otherwise "normal" materials, would it's completion "effectively" violate physical Law without actually violating it? ie: Even though you have, for practical purposes, removed matter/energy from the Universe instead of transforming it in a classical sense, it's still there.... presumably.

Manipulate the fundamental forces, such as we know them, in such a way as to make it "invisible" to them and.. "Poof" it's gone forever.

Yeah, it's a pseudo-science quackery post. But, actually making something truly invisible (not necessarily in the scope of the paper) is an intriguing notion. If there is no way to receive information concerning it (invisble) then it has no more bearing on our existence than that which lies outside of the Light Horizon of our Universe.

 

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IMO the invisibility is no different than putting it in a box - but this box bends light around it. No 'magic', other than any sufficiently advanced technology is indistinguishable from it.

 

[a_lost_packet_]

IMO the invisibility is no different than putting it in a box - but this box bends light around it. No 'magic', other than any sufficiently advanced technology is indistinguishable from it.

Very true. It's not magic and it really isn't "invisible" in any sense that includes more than light just appearing to pass "around it." In fact, light is passing through the metamaterial and being acted upon by it. So, it's light being altered, not ignored. The idea just sort of cascaded to one where an object was created that would be, in effect, invisible or unreactive/unresponsive to any outside fundamental physical forces. In effect, becoming "invisible" to the Universe. As I said, it was a pseudoscientific whacky post.

 

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Right now they're working with macroscopic metamaterials, but some day they'll be using nano-metamaterials - possibly in the form of controllable "programmable matter" like Carnegie Mellon's claytronics - which just could allow you to dynamically modify its optical properties (on/off etc.).

Soon after that happens you might end up looking in the direction of a loud noise and see a Stryker materializing in front of you.

 

[a_lost_packet_]

Right now they're working with macroscopic metamaterials, but some day they'll be using nano-metamaterials - possibly in the form of controllable "programmable matter" like Carnegie Mellon's claytronics - which just could allow you to dynamically modify its optical properties (on/off etc.).

Soon after that happens you might end up looking in the direction of a loud noise and see a Stryker materializing in front of you.

Programmable clothing..

Several science fiction authors have mentioned nano-like-metamaterials used in clothing to change colors, appearances in style and even transparencies... So, that waitress may decide to turn up the dial on the shifting transparencies revolving in fascinating colors around her jiggly bits in order to increase the size of your tip. Pun intended.