If one could build a macroscopic Schrodinger Cat state, one could communicate superluminally

We shall demonstrate that if one can construct a macroscopic state that maintains quantum coherence (a "Schrodinger Cat state"), then it can be used to send a superluminal signal. Since such a device has quantum properties, the experiment can perhaps also be done with a microscopic system, although we discuss in the conclusions why this might not be true. We take as our model an optical phase shifter of 180 degrees which we assume can be placed into a beam or not, and that the two possibilities can be quantum mechanically superimposed. This result depends upon being able to exploit two properties. One is that the device, which becomes a signal transmitter, can be entangled with the signal it is transmitting, thus becoming a GHZ state. The second is a controlled non-unitarity, for a subset of the complete Hilbert space, of a type that has already been used experimentally in two beautiful down-conversion interference experiments. The result is a superluminal transfer of information, but not of energy, using common experimental methods and a device that does not exist as yet, but should in principle be constructable. Although controversial, the result should not be ruled out by proofs that assume conservation of energy and/or unitarity over the entire quantum domain.