- #1
al onestone
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The failure of so-called "no-communication" theorems
In what we commonly refer to as "no-communication" theorems of quantum mechanics (QM), we make assumptions which are consistent with QM and with our knowledge of physical systems. But are these assumptions appropriate to a potentially would be faster-than-light (FTL) protocol for physics.
Let's first assume that out there in the mind of some brilliant young physicist (possibly not even born yet) is the real FTL protocol. If this is the case, then we must ask, are the assumptions of no-communication theory correct, and if they are correct are they appropriate to the FTL protocol? Do these assumptions cover all possible setups for such a protocol and show that within all setups there is no allowance for FTL? No.
First of all, most no-communication theorems assume an entangled system is the way to go. But is it though? These theorems are a reaction to the EPR/Bell type thinking. But QM had non-locality before EPR(1935) and Bell(1960's) showed up. QM has always had interference between optical pathways, even if the optical pathways are separated by more than the uncertainty in position, as long as the optical pathlengths differ by no more than the uncertainty in position. Some how the coherent superposition is retained even though the paths are separated by a length longer than the uncertainty. As long as the "which path" information is not present in the preparation.
Hmmm, has any of these so-called "no-communication" theorems made up a rule in QM about "which path" information and then assumed this rule in the setup of the theorem. I think not. To put it bluntly, all no-communication theorems simply use "in the box" type assumptions and then low and behold, there is no FTL communication in the box. But if they venture outside of that box they just might become that great young theorist yet.
In general, al onestone states that it makes no sense to make an assertion about what one "cannot" achieve, because it only expresses the limitations of current theory.
In what we commonly refer to as "no-communication" theorems of quantum mechanics (QM), we make assumptions which are consistent with QM and with our knowledge of physical systems. But are these assumptions appropriate to a potentially would be faster-than-light (FTL) protocol for physics.
Let's first assume that out there in the mind of some brilliant young physicist (possibly not even born yet) is the real FTL protocol. If this is the case, then we must ask, are the assumptions of no-communication theory correct, and if they are correct are they appropriate to the FTL protocol? Do these assumptions cover all possible setups for such a protocol and show that within all setups there is no allowance for FTL? No.
First of all, most no-communication theorems assume an entangled system is the way to go. But is it though? These theorems are a reaction to the EPR/Bell type thinking. But QM had non-locality before EPR(1935) and Bell(1960's) showed up. QM has always had interference between optical pathways, even if the optical pathways are separated by more than the uncertainty in position, as long as the optical pathlengths differ by no more than the uncertainty in position. Some how the coherent superposition is retained even though the paths are separated by a length longer than the uncertainty. As long as the "which path" information is not present in the preparation.
Hmmm, has any of these so-called "no-communication" theorems made up a rule in QM about "which path" information and then assumed this rule in the setup of the theorem. I think not. To put it bluntly, all no-communication theorems simply use "in the box" type assumptions and then low and behold, there is no FTL communication in the box. But if they venture outside of that box they just might become that great young theorist yet.
In general, al onestone states that it makes no sense to make an assertion about what one "cannot" achieve, because it only expresses the limitations of current theory.