The discussion centers on the feasibility of faster-than-light (FTL) communication using entangled photons, referencing Alain Aspect's experiments. Participants clarify that while entangled photons exhibit correlations, they cannot be used to transmit information instantaneously. The consensus is that the randomness inherent in photon polarization prevents any reliable transmission of data, as demonstrated through Bell test experiments. The key takeaway is that despite the intriguing nature of quantum entanglement, it does not facilitate FTL communication.
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DrChinese said:There are 2 observers, Alice and Bob. They get a stream of photons arriving as you say, perhaps 10. They EACH have a polarizing beamsplitter and 2 detectors. When Alice gets a dectector hit on the first detector, she marks it a +. The other detector registers as a -. Ditto for Bob.
Alice can vary her beamsplitter orientation so she can "send" a message. (Not really of course as we will find out.) Bob holds his beamsplitter fixed and steady so he can receive a "message". The beamsplitter separates the photons to one of the 2 detectors as mentioned, and he records a + or a - according to which of his 2 detectors fires.
Now what does Bob see when he records his results? He see a random series of + and - results, something like this:
++-+-+---+
Since the "message" is random, no information is received. It doesn't matter what Alice does, Bob's message is totally random by any measure. That is because the source of the entangled photons is random itself. The pattern that indicates there is entanglement is ONLY evident when Alice AND Bob's results are correlated.
IMP said:But the results Bob gets could be thought of as 1101010001 (++-+-+---+ as you stated). Just because Bob cannot confirm the string until he and Alice get together does not mean the string is random. Correct?
Albert V said:A question just for fun:
It seems that it is the beamsplitter in the quantum eraser that ruins our FTL communication and Nobel. What if we throw out the beamsplitter and insert a black box containing a device that inserts a mirror by random. We still have no which path information and no polarizer that interacts with the system, but will we have the interference fringes?
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Descartz2000 said:Refuting the existence of free choice experiments is a way to explain the results without turning to FTL.
That's probably true. Still, one can use logic (rather than an experiment) to show that "free choice" is not compatible with some theories. For example, both classical and quantum mechanics interpreted as UNIVERSAL theories (by an "universal" theory I mean a theory for which one assumes that EVERYTHING, including the human mind, is completely described by that theory) are not compatible with "free choice".DrChinese said:I don't consider the hypothesis of "no free choice" to be science (any more than the hypothesis of God is science). And I don't think it is possible to refute free choice by any experiment (just as it is not possible to refute the existence of God).