|Demetrios A. Kalamidas|
Recently Demetrios Kalamidas, who has a degree from CCNY and is currently working at New York nanotech company Raith USA, has proposed an FTL signaling scheme using a novel kind of quantum measurement. His proposal (which I have called KISS, for "Kalamidas's Instant Signaling Scheme) has been accepted for publication in the March 2013 issue of the Journal of the Optical Society of America. A preprint version with essentially the same content as Kalamidas's JOSA article appears here.
The KISS proposal is based on the observation that one member A of an entangled pair AB can show interference effects when its distant partner B is measured in a manner that "destroys which-path information". These interference effects vanish when B is measured in a manner that detects which of two paths B actually took. On the face of it this looks exactly like superluminal signaling were it not for the fact that in order to see this interference, "coincidence information" about results at B must be sent (at light speed or slower) and this information is necessary to separate the superluminal signal from noise.
One way of looking at this situation is that, using entangled particles, superluminal signals can indeed be sent. But these FTL messages are encrypted in a perfectly unbreakable cipher that can only be decoded using a key sent at light speed or slower. So far all schemes to send signals FTL have failed due to the necessity of sending this decryption key by conventional means.
The KISS scheme purports to be different. Kalamidas proposes to destroy "which-path" information in a novel way (that involves mixing the photons that carry this information with a kind of light that possesses an indefinite number of photons). Kalamidas calculates, in his JOSA paper, that this clever new way of introducing ambiguity into the which-path measurement of the B photon has an immediate effect on its A partner -- an effect that is "in the clear" and does not need to be decoded.
Although it is evident that this proposal is a bare naked FTL communication scheme, Kalamidas modestly entitles his paper A Proposal for a Feasible Quantum-optical Experiment to Test the Validity of the No-Signaling Theorem.
|Sketch of the KISS proposal (from JOSA article)|