Quote:
Originally Posted by dcmike It was indelibly engraved in stone tablets that nothing can go faster than the speed of light - but a German professor proved that wrong by sending and then retreiving data (intact) at nearly five times the speed of light. That opens up the possibility of some sort of time travel - even if only retrieval of information. |
Quote:
Originally Posted by Moontanman I'm tired of this discussion, do you have a link to this experiment, I would like to read about this. |
We’ve discussed the experiment in frustrated total internal reflection and quantum tunneling described in Nimtz and Stahlhofen’s 2007 paper
“Macroscopic violation of special relativity” in threads
”We have broken speed of light”,
”FTL signaling via frustrated total internal reflection”, and, most in-depth, I think, around post
”A theoretical way to communicate FTL/back in time & an additional Clarke-esque law” of thread “FTL Communication”. The
wikipedia article “Günter Nimtz” also has a brief description of the experiment and various responses to it.
Assuming, as one may from
the paper’s Feynman diagram (Figure 2) that the tunneling time is actually zero, the actual speed of the signal is

, where

is the total light path length through the prisms,

is the gap between them,

is the refractive index of their material, and

the speed of light in vacuum.
The paper gives

and (indirectly)

, from which we can calculate that

when

. The paper does not describe

, other than indirectly in the Figure 1 illustration, where it appears to be about 0.1 m, a distance that would not result in a signal speed greater than c. The
wikipedia article “Günter Nimtz” states
Photons can be detected behind the prisma at the right side until the gap exceeds approx. one meter
, which would.
Clearly, an authoritative value for

is critical for the reader to determining whether the experiment demonstrates actual FTL signaling. I find the lack of such data, and of experimental verification by other scientists, suspicious and disturbing
In short, and in my opinion, the FTL effect illustrated and measured in Nimtz and Stahlhofen’s experiment are not prohibited by physical law. The apparent contradiction between special relativity, which prohibits FTL signaling by postulate, and quantum electrodynamic, which does not, is removed by the observation that SR is a classical, not a quantum mechanical, theory. However, QM typically assumes that macroscopic effects are statistically bound to the postulates of relativity, leaving me uncertain of the implications of the described effect.
I’ll started a thread “Is Nimtz and Stahlhofen’s FTL signaling for real?”, to discuss these questions, soon. I’ll also split this thread as necessary to keep it on its original topic, while not losing its many off-topic posts.
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