FTL signaling via frustrated total internal reflection

[Jay-qu]

Certainly, I don't expect a proper analysis would reveal propagation faster than c but I don't see it as a matter of photons getting lost. It's a matter of analysing an incoming wave packet and seeing how its Fourier transform is altered by the exponential factor of the evanescent wave. Anyone up to doing the integrals?

Maybe depends how hard they are ;) if not I can take them to uni and get one of the professors to take a look :)

[Qfwfq]

Maybe depends how hard they are :(

Hard enough. :phones:

 

Actually I put it a bit sloppily yesterday. The idea is that, for a given incident wave packet, you need to multiply its Fourier transform by the exponential factor and then re-transform to get the emergent wave packet according to the distance between the two prisms.

[Jay-qu]

Ive just learned how to do fourier expansions in the last few weeks :phones: but somehow I think the rest will fly ominously above my head..

[LaurieAG]

Certainly, I don't expect a proper analysis would reveal propagation faster than c but I don't see it as a matter of photons getting lost. It's a matter of analysing an incoming wave packet and seeing how its Fourier transform is altered by the exponential factor of the evanescent wave. Anyone up to doing the integrals?

 

Hello Q,

 

I'm not too sure about it being a standing wave as a standing wave should only produce a photon at one of the detectors or the other not both. Multiple moving wave pulses (1 photon equivalent) could be recorded sequentially at both detectors if the back of the prism acted like a mirrored surface.

 

The vectors 'Tv' and 'Th' in the diagram can be obtained by mirroring the high and low points of a moving pulse at the back end of the prism. While the photon isn't exactly a wave the mirror vectors of these two wave points (top & bottom) will appear as they do in the diagram.

 

It would be good to see exactly how the experiment was undertaken and have copies of the raw data sent and captured, before going any further maths wise, than the basic vectors shown in the diagram.

 

Also, It would be interesting to know the density of the glass used in the prisms, their exact corner angles (i.e. are they 60 degrees?) and the atomic bonding angles of the atoms in the glass (and any impurities/doping).

[Qfwfq]

Where did I imply it being a standing wave, Laurie?

 

Ive just learned how to do fourier expansions in the last few weeks :phones: but somehow I think the rest will fly ominously above my head..

Actually, I imagine you're talking about a Fourier series, which is suitable for periodic functions. The Fourier transform I mean is tricky and entangled with distribution theory as well. You could, however, ask your professors if they can make anything out of it, I would need to do quite some looking up before drawing any reliable conclusions.

[Jay-qu]

:phones: right you are Q

 

I had a talk to one of my lecturers about this experiment and he wasnt terribly surprised.. he seemed to think that eventually someone would show that it was unable to be used for FTL communication - though he did still think it warranted a closer look

[Qfwfq]

What I've not yet mentioned is the matter of how they can claim experimental verification.

 

First, the difference in optical path can't be much more than a wavelength (0.03 m in their case) or two. They must have coincidence counting with a resolution of the order of tenths of a nanosecond. Second, what they are doing is detecting different photons from the same original pulse, so if the coincidence counting is to be meaningful this must have a duration of the same order, which means not much more than a period or so and this in turn means a very broad spectrum. This makes the optics trickier to analyse and, especially, hardly accurate to state the wavelength they are using which instead they give rather precisely as 32.8 mm.

 

I'm not so sure how reasonably they can claim such an interpretation of their measurements.

[Erasmus00]

What I've not yet mentioned is the matter of how they can claim experimental verification.

 

Well, regardless of how this experiment was done, tunneling is certainly a well known theoretical phenomenon. I think the question at hand is - can tunneling allow for ftl signals? why or why not?

-Will

[LaurieAG]

Well, regardless of how this experiment was done, tunneling is certainly a well known theoretical phenomenon. I think the question at hand is - can tunneling allow for ftl signals? why or why not?

-Will

 

Hi Will,

 

It all depends on what 'tunnelling' is defined as.

 

Here's a more recent reference The properties of photon tunnelling in a frustrated total internal reflection structure with an indefinite metamaterial slab

 

The tunnelling time and lateral shift of photon tunnelling through the frustrated total internal reflection structure containing indefinite metamaterials are obtained by employing the stationary-phase approximation. It is found that the photon tunnelling only occurs when the barrier is thin enough. For the indefinite metamaterial with one-sheet hyperbolic dispersion, the anomalous total reflection occurs, and the negative lateral shift and tunnelling time can be obtained. The negative tunnelling time indicates that superluminal propagation could be observed when a photon tunnels through the indefinite metamaterial. Both lateral shift and tunnelling time tend to a saturation value, respectively, as the barrier thickness increases. Moreover, the dependence of properties of four kinds of indefinite metamaterial on the thickness, the permittivity and permeability tensors is discussed.

 

Total internal reflection - Wikipedia, the free encyclopedia

Stationary phase approximation - Wikipedia, the free encyclopedia

 

So, it looks like, for a start, the static wave is a combination of other waves (for both detectors to get hits) at the same 'time' and the material isn't just pure silica.

[Qfwfq]

Well, regardless of how this experiment was done, tunneling is certainly a well known theoretical phenomenon.

Nobody seemed to be doubting this. In fact it has long been observed and in comes into many different phenomena.

 

I think the question at hand is - can tunneling allow for ftl signals? why or why not?

That's pretty much what I was talking about. :D

[Farsight]

Hi guys. You know me as Popular, but Tormod has allowed me to change my name to Farsight for the sake of consistency. Thanks Tormod. This is really a test post, but can I chip in to say that IMHO faster than light travel is not possible, and IMHO any phenomena suggesting that this is not the case is a misunderstood phenomena. I hope to be able to give some supporting information to back this up in about a week.

[LaurieAG]

Hello All,

 

Attached is a very rough diagram of the atomic structure at the back of the prism where the 'tunnelling' occurs. I suspect that the element used to dope the high density silicon may be congregating at the edges of the prism as a part of the manufacturing process.

 

The doping element could play a crucial part in the whole process if you consider the mechanism used in Tormods recent news post on Photon Transistors.

 

http://hypography.com/forums/technology-news/12638-photon-transistors-supercomputers-future.html

 

After all, we have the silicon channel, the pulse and other atoms in the structure.

[arkain101]

I think the real question at hand here is would ever have to fear a hologram being from killing us... ;P

 

In this joke I mean to show that what is holographic is relative art, of compound thoughts that can not physically interact with the world.

 

What is non holographic is relative art representing that which will and can interact with the world around it.

 

Just like a painting of a green valley is a green valley from afar, but also a bumpy surface of indistinguishable representations, or even a far off green dot, of meaningless representation.

 

The fact is, There is a canvass, and it can smack you in the head fairly hard if swung by a crazed starving artist who has had enough of the critiques on his please love me for what I have done pieces of paper.