Faster than light communication and breaking entanglement

hum. what does this mean?

phys.org...

it looks to me like it says you can send information without sending particles or energy the classical way. so far all quantum communications had a to have a classical component and it meant that no information could actually take place faster than FTL. but this seems to say that is not needed. but it also looks like they take pains to say at least twice that it applies to unknown information... so i am confused about whether this is FTL communications or not.

a reply to: stormbringer1701
www.nature.com...

On the other hand, during the state transfer process, although the photon does not travel to Bob's site, the optical path length it travels is near 2MN times that of the distance between Alice and Bob, so the scheme here cannot realize the superluminal communication. Therefore, the present scheme achieves the quantum counterfactuality without contradicting any existing physical law.

But it is a cool setup, as the photon is getting the quantum info without physically visiting Bob. I'd say wait and see if it can be confirmed experimentally.


Oh yeah, not to forget, the chance for the transfer to work is claimed to be at 50%. So it is also nondeterministic.

If you have an entangled pair, can a past me and future me see changes if the now me changes the state of the pair?

originally posted by: moebius
a reply to: stormbringer1701
www.nature.com...

On the other hand, during the state transfer process, although the photon does not travel to Bob's site, the optical path length it travels is near 2MN times that of the distance between Alice and Bob, so the scheme here cannot realize the superluminal communication. Therefore, the present scheme achieves the quantum counterfactuality without contradicting any existing physical law.

But it is a cool setup, as the photon is getting the quantum info without physically visiting Bob. I'd say wait and see if it can be confirmed experimentally.


Oh yeah, not to forget, the chance for the transfer to work is claimed to be at 50%. So it is also nondeterministic.

yeah but it seems to me barring some other restriction you should be able to send redundant bits and use statistics to determine what the intended bit state is and perhaps use the weak measurement principle to avoid destabilizing everything.

originally posted by: stormbringer1701
hum. what does this mean?

phys.org...

it looks to me like it says you can send information without sending particles or energy the classical way. so far all quantum communications had a to have a classical component and it meant that no information could actually take place faster than FTL. but this seems to say that is not needed. but it also looks like they take pains to say at least twice that it applies to unknown information... so i am confused about whether this is FTL communications or not.

What does this mean?

It means what quantum mechanics said from the get go: wavefunctions, not particles, are the fundamental element of the physical dynamics. Even the scientists think it's baffling because they're still biased towards classical physics thinking. Having a clear particle means that you are thinking in a Fock state, an eigenstate of the particle number operator. The state need not be like that.

The phys.org article equates "interaction" with "transmitting particles between them", which I would dispute. No interaction means no matrix element, no operator, no nothing changing free evolution of the wavefunction, in which case there really is no effect at all.

There's a familiar case that people forget about: Higgs field. It has a non-zero vacuum state and it interacts with all sorts of fields and their particles, except photons, all the time. How often does a Higgs particle (the boson) get created in everyday life? Almost never, it's over 100 GeV in mass! So you get a Higgs interaction without Higgs particles. Mysterious? No.

It's finally time to believe quantum mechanics for real: the element of state is the wavefunction in a Hilbert space of functions and it is not a classical field in x,y,z,t on which there are only local differential operators, in contrast to classical E&M, fluid mechanics, and gravity.

a reply to: stormbringer1701
The correspondence principle states that quantum mechanics has to reproduce classical mechanics in the macroscopic limit. This means (to me), you can not use it to break classical mechanics, implement FTL and co.

originally posted by: moebius
a reply to: stormbringer1701
The correspondence principle states that quantum mechanics has to reproduce classical mechanics in the macroscopic limit. This means (to me), you can not use it to break classical mechanics, implement FTL and co.

It depends on what exactly you mean by 'macroscopic limit' and therein is the trick. Correspondence principle is a good guide but isn't a rigorous theorem (there are some in this space).

Superconductivity is a macroscopic and completely quantum mechanical effect. But it's true that there are not many of them.

I mostly agree with you, I think it's very very unlikely but who knows? Suppose you could in fact maintain a macroscopic entangled and fully quantum state, and then 'observe' it with such small and delicate means that there is little collapse?

Maybe you could get FTL comm if you could string a superconductor along the path.

originally posted by: mbkennel

originally posted by: moebius
a reply to: stormbringer1701
The correspondence principle states that quantum mechanics has to reproduce classical mechanics in the macroscopic limit. This means (to me), you can not use it to break classical mechanics, implement FTL and co.

It depends on what exactly you mean by 'macroscopic limit' and therein is the trick. Correspondence principle is a good guide but isn't a rigorous theorem (there are some in this space).

Superconductivity is a macroscopic and completely quantum mechanical effect. But it's true that there are not many of them.

I mostly agree with you, I think it's very very unlikely but who knows? Suppose you could in fact maintain a macroscopic entangled and fully quantum state, and then 'observe' it with such small and delicate means that there is little collapse?

Maybe you could get FTL comm if you could string a superconductor along the path.

As with all things in life we find exceptions. And yes I think you could with a superconductor. But would the gain be worth it?? If FTL communication is possible it would involve hidden dimensions. Meaning our particles always share this dimesion no matter how far apart we move them. If they exist we may be able to literally use these dimensions for communication. But even that isn't entanglement that would be using the same method they use to communicate. Entanglement will always have its limitations.

A lot of good science in here, but most of it does not address the fundamental aspect of the uncertainty principle. The entagled particle is undefined until it is observed. Observed means to attempt to sense the value, however that is accomplished. That act determines the spin of that particle. I fail to find any methods as described so far as to not prevent or delay the instant polarity being realized on the other end, and totally unsolicited.

a reply to: charlyv
The OP claimed faster than light communication is possible.
Most people replying are saying that it's never been demonstrated, and even the OP posted a Michio Kaku video saying it's probably not possible because the FTL information transmitted is random and not useful.

I can't figure out which side of the debate you're arguing for, if any?

a reply to: mbkennel

Or maybe not.

While being a quantum mechanical phenomenon, superconductivity doesn't break classic physics. I don't see how superconductivity would be related to FTL at all.

originally posted by: Arbitrageur
a reply to: charlyv
The OP claimed faster than light communication is possible.
Most people replying are saying that it's never been demonstrated, and even the OP posted a Michio Kaku video saying it's probably not possible because the FTL information transmitted is random and not useful.

I can't figure out which side of the debate you're arguing for, if any?

I am not arguing for any "side" per se, although I do agree with Michio's comment. The uncertainty principle is a mainstay theory. In order to dismantle it, it takes extraordinary science and mathematics, with proofs that are just not there.

I can see no way that FTL communication could be possible without unseating that fundamental theory, which holds for so many many other fields of physics that rely on it as a fundamental truth. I know that theories are really stakeholders that science always requires to mark our current understanding of reality, however this one is such a biggie, a modification to it would have to hold for everything else that has been mathematically built upon it.

originally posted by: Arbitrageur
a reply to: charlyv
The OP claimed faster than light communication is possible.
Most people replying are saying that it's never been demonstrated, and even the OP posted a Michio Kaku video saying it's probably not possible because the FTL information transmitted is random and not useful.

I can't figure out which side of the debate you're arguing for, if any?

Of course it's random. You keep debating against things that were never said.

Tell me, on my multi channel set up on which am I not sending random information? Where did I say I was trying to send useful information on any 1 of the 3 channels in a multi channel setup?

Again, you have to stop debating against things that I never said. It just looks silly.

originally posted by: stormbringer1701
hum. what does this mean?

phys.org...

it looks to me like it says you can send information without sending particles or energy the classical way. so far all quantum communications had a to have a classical component and it meant that no information could actually take place faster than FTL. but this seems to say that is not needed. but it also looks like they take pains to say at least twice that it applies to unknown information... so i am confused about whether this is FTL communications or not.

Great article!

I've been talking about this for awhile now. Here's a paper that was written awhile back.

The wave-function is real but nonphysical: A view from counterfactual quantum cryptography

arxiv.org...

Also here:

As Salih says: "I believe the question of how information gets from Bob to Alice is a deep one speaking to the heart of the debate about the reality of the quantum state: if physical particles did not carry information between sender and receiver, what did?"

Link

originally posted by: neoholographic
Tell me, on my multi channel set up on which am I not sending random information?

But you are sending random information. Michio Kaku said it and he's right, and you said you're not disputing his video. That's all you're sending faster than light is random information.

All the tricks you talk about using to make the information non-random require light speed or less to accomplish and we already have that with our cell phones, so the main reason quantum entanglement is being investigated is for use in cryptography where it's useful even if at light speed or less. The papers you cite talk about cryptography based on entanglement, not FTL communication.

a reply to: Arbitrageur

What tricks are you talking about exactly?

Spell out these tricks.

Why do these "tricks" require light speed or less when I'm sending random information on each channel? You're not making any sense.

You're saying I'm using "tricks" but why do I need "tricks" to send random information faster than light?

originally posted by: neoholographic
a reply to: Arbitrageur

What tricks are you talking about exactly?

Spell out these tricks.

From your OP (and numerous other posts) talking about signal to noise.

originally posted by: neoholographic
So the photons state of spin up or spin down wouldn't be transmitting the information but the strength or lack there of, when it comes to the signal to noise ratio would.

Why do these "tricks" require light speed or less when I'm sending random information on each channel?

Without the tricks, random information is all you have. That's not FTL communication, that's FTL random information.

You have been asked numerous times to explain how you'd determine signal to noise faster than light and all you can provide for examples are cases where it's measured at light speed or less. In the last two examples you provided on page 12, the effective speed is half the speed of light, because the information is sent at light speed to the second party, who then sends it back to the first party at light speed, where signal to noise is measured when the first party compares what was sent to what was received back. So it takes the first party twice as long to measure signal to noise as it does for them to simply send a light speed message to the second party.

originally posted by: neoholographic
a reply to: Arbitrageur

What tricks are you talking about exactly?

Spell out these tricks.

Why do these "tricks" require light speed or less when I'm sending random information on each channel? You're not making any sense.

You're saying I'm using "tricks" but why do I need "tricks" to send random information faster than light?

If using your methods all you have is chanels with light running through it. When we say signal to noise here's what is Meant. If we send a laser we create entangled pairs and send our beam to the moon. I capture the other one here on earth. Now you have laser light when you look at it it's complete noise. If monitored you get what appears to you to be totally random. This means you have nothing to observe because you don't know what to look for. Now let's say I send you a code if you were. Maybe a count maybe frequency changes etc.

Now once I send you this know you can compare the two and you can see its not all entirely random. Now you see a pattern in the noise. However not a complete match this is the noise. Noise occurs a couple of diffrent ways one being creating entangled particles others will not be In our beam. Than the further the distance the more likely that they break entanglement before you can check. So anytime we have entangled particles wrong have more that are not. so in order for us to find the ones entangled what we call the signal you need help. In your examples you don't understand how to detect entangled particles but the uncertainty principle fights you until we can compare them.