“you would actually allow communication of information into the past” if you assume relativity to be true, yes. But if superluminal informational transfer is occurring, then relativity is false. You’re making a circular argument without realizing it. Last but not least, even if signalling isn’t possible, it does not imply that particles aren’t communicating with each other faster than light. There is no non circular argument proving this and it’s just a repeated dogma by some physicists. See the works of Tim Maudlin (he actually met John Bell) who argues against this dogma

My point is that entanglement doesn’t violate relativity, and relativity (which predicts numerous other confirmed phenomena and is known to work in every other circumstance) can thus be extended to cover this case as well. If you’re insistent that physicists are just spouting dogma, why did you ask the question? What’s your alternative to relativity? Why does relativity have to be wrong even though it makes all these accurate predictions and allows our technology to work? This seems more about your perception of relativity than the question you’re purportedly asking.

do you understand that superluminal informational transfer would violate relativity? If so, then your argument amounts to “even though we see measurement outcome A determining measurement outcome B, and this initially seems to violate relativity, it can’t violate relativity because….entanglement doesn’t violate relativity”. It’s literally a circular argument. The alternative would be having a preferred foliation of space time (just as in the past).

Okay, I’ll rephrase: “no information transfer occurs, so relativity is not violated.” Is that good enough? You were the first one here to invoke the no-signalling theorem, which is relativistic in origin; I cannot understand why you are now asking me not to use it in my answer.

Newtonian mechanics makes predictions that work too, but it’s wrong. Same applies to other theories that were replaced by newer theories. The newer theories just also explained why the incorrect theories still worked in certain contexts/approximations. So if I had to guess, this new future theory would probably violate relativity but still explain why relativity predicts certain things

if you’re saying that the no signalling theorem is relativistic in origin, then you’re admitting that the theorem is circular. This is because superluminal information transfer would obviously break relativity

I also wrote a whole paragraph about why entanglement doesn’t transfer information, without reference to no-signalling. Did you read any of that? Also: why did you even bring up the no-signalling theory in the first place if you have such a problem with it?

@comtrolgroup I only mentioned it in passing, and even if the theorem is correct, it implies you can’t signal, not that particles aren’t communicating with each other. I’m not sure why you’re conflating the two.

Jsyk, those are the same thing. “Signalling” means “transfer of information between particles”. Moreover: did you read the part of my answer where I explain quantum-mechanically why entanglement doesn’t transfer information?

I mean- is that part nonsensical to you? How could I clarify it?

You don’t need any relativity to show that entanglement doesn’t transfer information; I don’t know why you’re going after relativity all of a sudden.

@controlgroup signaling does not mean that because

One of the reasons that the no signalling theorem seems to work

Is because Alice cannot control her measurement outcome

It is random from her perspective

yes, which I explain in my answer

However this says nothing about the existence of a link between particles that may be superluminal

So signalling has to do with practicality not just the existence of a link between particles

But even the no signalling theorem, as you admit, assumes relativity

There is a superluminal effect, yes, but not one that allows for information transfer FTL, so that effect is exempt of the lightspeed limit

But if Superluminal information transfer was happening, relativity would be broken.

So you can’t assume relativity to argue against something that may violate relativity

The no-signalling theorem is not “relativity says no, so no FTL signalling”, it’s “entanglement doesn’t transfer information, so no FTL signalling; by the way, that makes relativity okay with entanglement.”

but the way they show that entanglement doesn’t transfer information is ultimately by “relativity says no”. In your comment, you talk about how it would lead to backwards causation. It can only lead to that IF relativity is true

It’s… not.

Where are you getting that info?

Who’s “they”?

I showed it with exclusively-quantum-mechanical means. Is that not sufficient?

The theorem in general. Look, can you show how it would lead to backwards causation without assuming relativity?

No, no, I mean a citation. Who did you read that said that proved no-signalling that way?

arxiv.org/abs/quant-ph/9906036

This paper goes over the various no signalling theorems

And shows how it is circular

Looking through it right now - it’s making the same mistake you are.

What exactly is the mistake?

Be specific

To presume that you can’t derive no-signalling from only quantum mechanics.

It’s just a fact: two entangled particles do not transmit information to one another upon collapse. You can test this mathematically in any formalism of QM. The fact that it agrees with relativity comes after you get that result.

Now: why do you and those authors bother going after relativity? It works. I don’t see either of you trying to provide a new theory that makes more/better predictions.

you can show that there is a problem with a theory without having a new one yet

Think of it this way

And this argument is purely logical

And what is the problem? What has relativity predicted inaccurately?

Alice measures spin up. Bob makes a measurement

Bob’s measurement now has to be spin down

Bob can’t know that the particles were entangled without comparing his measurement to Alice’s.

Yes, but where did I say he knows?

All I am saying is his measurement has to be spin down

Correct?

If he doesn’t know they’re entangled, he hasn’t gained information from Alice, he’s just measured his own local particle.

But we’re not talking about Alice and Bob communicating with each other

We’re talking about where the particles are

Okay, sure. Bob measures spin down.

those are two different things

Yes so now if you insist

That there is no informational transfer

Between the particles

Then the only alternative is true action at a distance. Somehow,!l instantaneously, Alice’s measurement outcome affects Bob’s measurement outcome (note not that Alice can use this to signal Bob)

Yes. I stated that in my answer.

And to me that seems ludicrous for the same reasons as Newton who argued against action at a distance

In order to show that the particle isn’t communicating with another, you have to assume relativity

You don’t.

But relativity would be broken if they were

Okay can you give me an argument

Yes, but you don’t need to assume relativity to show that.

Without assuming relativity

Alright, deal.

Say I’ve got a particle. I measure it: spin down. Have I communicated any information to you, who measured a particle a short time afterwards to see spin up?

I couldn’t have: how do you know that I did the measurement?

Exactly.

You haven’t seen me make the measurement yet, so you just make a measurement at random and get spin up. Great, but how do you know that I hadn’t already collapsed it to that state, or if you just collapsed mine to spin down?

I don’t

We can only identify that the particles were even entangled in the first place by comparing our measurements.

So, how do you plan on comparing our measurements at a distance?

But if that is accurate, that proves that I cannot practically use my measurement to communicate to Alice in such a way that she can tell the difference between her measurements being random vs coming from me

Moreover, how do I control the result of my measurement to choose which bit gets sent to you?

So you’re conflating whether I can communicate this information to Alice

With whether the particles are communicating

The paper goes over this

Basically there is a difference between

A) the particles having some sort of connection between them that is superluminal

Humans don’t need to be involved. Our only communication apparatus is a radio and the particles; can’t communicate through the radio or the particles, can’t communicate with each other.

B) Alice communicating to Bob her measurement outcomes in time

The particles do have a superluminal connection, just not one that transfers information.

That’s fine but that would still be communication AFTER the measurement is already done. You actually have to set up a signalling system at the end of the day. That’s where the practical mechanism comes in

Okay so then I have a question

Think about it this way: I entangle two particles. How many bits of information are stored between them?

How is this connection developed? Think about it

What is causing them to have a superluminal connection?

2

Just look at the wavefunction of two scattering electrons. It’s pretty clear, actually.

(I believe, could be wrong)

But the wave function collapses instantaneously all over space

Unless you believe the wave function is epistemic but other theorems have already proven that can’t be the case. See the PHR theorem

PBR

@Syed No, I’ll accept that

That’s ok

I really suggest you read the paper I linked. It goes over the two things you are conflating

And I’m pointing out that it’s being pedantic about what English we use to describe the situation.

There’s another really good way to think about this in terms of total information content that will resolve things.

I mean what we’re really interested in is whether or not there is a physical medium between the two particles, or some sort of link, or some sort of connection. So far, there is no proof against that. There is only proof against it for signalling purposes.

Bohmian mechanics is an example of a deterministic theory where the non locality is inherent to it

Let's say I know that my particle and yours are entangled. The total information present in the system is one bit: if I read spin up, I also know that the other particle is spin down by deduction, and vice versa. There's one bit of information to be had.

So if I measure the system and learn my particle's spin (up/down, 1 bit), I have extracted all of the information from the system. There is no information from the distant particle for me to have: the information about the system as a whole is encoded in both particles.

“ Great, but how do you know that I hadn’t already collapsed it to that state, or if you just collapsed mine to spin down?” if we assume a preferred foliation, one of them occurs before the other globally.

@Syed Doesn't matter. You collapse it so you read spin down, sure. Then, when I read the state, I get spin up. I have extracted one bit (all) of information from the system, which I could well have gotten on my own.

Yes but how is it encoded in both particles if it is non local without a medium?

You are simply saying that they will always be the opposite, not how

And the QM formalism is just an equation ultimately

Because to entangle they have to actually be at the same place at the same time. They get entangled, and at that local event the information gets encoded in both; that information will remain encoded there until measurement at any later time, regardless of separation.

this is what you’re saying: “they are entangled locally, and they remain entangled at large distances.” You are not answering how

I could give you the quantum mechanical explanation, but I don't think you would understand it. I think then I'd get criticizes for just spouting math you don't understand, and then I'd still be the villain.

It’s not that I don’t understand it

QM is a mathematical formalism

Let me give you an analogy

Imagine if every time I jumped, a dog on the other side of the universe jumped

And every time I clapped, a dog on the other side of the universe clapped

Okay, cool. How do I know that the dog is jumping/clapping at the same time as you?

Without going there and checking, I mean.

now look let’s call the state of clapping C jumping J

you can write a mathematical statement describing this

Using the same QM formalism

Yes, I can, but how do I know that jumping/clapping are correlated?

But the formalism would merely describe what’s going on. It would not explain how

How do I know that you jumping implies that the dog is also jumping?

You figure out the correlations after the fact

@Syed Correct. That is how mathematical models work.

That’s fine

@Syed At what speed?

When is "after the fact"? Since you're so obsessed with how, tell me how I get the correlation info.

Let’s assume we figure this out under the speed of light. However let’s assume we figure out that this correlation cannot be explained by local hidden variables

Imagine there’s a someone recording whether the dog jumps or claps

So you're assuming that you can do FTL info transfer and then proving from that that FTL info transfer is possible?

Haha, no.

And I record whether I jump or clap

@Syed When do you learn that the records are correlated?

No I’m saying QM is a description of these non local correlations. It is not an explanaation of them

@Syed Yes, that is how models work.

No, a scientific theory also explains things

I’ll give you an example

It super doesn't.

We frequently attach explanations; they are not formally part of the theory.

You’re aware of the gravitational law right

Gm1m2/ square of the distance

Yep. Explain it! What's causing that to happen?

(English, no math.)

This was ultimately similar to QM. We had an equation that describes a non local correlation. This did not explain how it’s happening. It posited action at a distance

Then, Einstein came

And the theory of general relativity came

Yes, another math equation.

And Einstein said wait a minute this ain’t action at a distance

No, it gave an explanation, the curvature of space time. And then it made predictions in regards to gravitational waves

Which were then observed

Newton admitted his equations were not complete that’s the point

@Syed Nope. We call it that because it's simpler to explain to laypeople (e.g. you). General relativity is a description of the set of the Universe's events as a manifold, and predicts the dynamics with a set of equations, nothing more.

Because his equations showed instantaneous correlations without a force propagating through a medium. The “controlgroup” of that time would have similarly argued that no information is being transferred between two masses and that its instantaneous

Identify theories are not just math, you’re simply wrong about that

@Syed Anyways: when do you learn about these jumps/claps being correlated?

We don’t invent postulates to explain things to people. We invent them because they are the explanations

After when we compare results

@Syed I'm literally a professional scientist. I work with GR more often than you are on philosophy.stackexchange.com.

@Syed Which happens how long after the jumping/clapping take place?

If we can compare results instantly, congrats, we can do FTL communication! Is that what you're saying?

Yeah and most scientists aren’t aware of the foundations of QM. It’s because they’re not paid to worry about it

Tim Maudlin talks about this here: youtu.be/qG5PzdbtoQo?si=2TBAADWPz8JtViWw

Please, with the question-dodging. How do you propose we compare correlations instantly?

“ “It may be that we have to admit that causal influences do go faster than lighT”

John bell

We don’t compare correlations instantly

@Syed Then how do we do it? How do we do it faster-than-light?

The burden would be on you to show that we can’t just like in QM

If we don't compare at all, how do I even know that our particles were entangled in the first place? How do you know you're not just measuring a solitary particle?

But whether or not we can

Is DIFFERENT

From whether me and the dog are somehow linked

@Syed Wrong. It is not on me to disprove. It is on you to prove.

Through a. Physical process

No it isn’t!

@Syed Russel's teapot??

The no signalling theorem has the burden of proof

Because it is making a claim for the non existence of something

"Russell's teapot is an analogy, formulated by the philosopher Bertrand Russell (1872–1970), to illustrate that the philosophic burden of proof lies upon a person making claims, as opposed to shifting the burden of disproof to others."

no if I make an argument against god I have the burden

The no signalling theorem is a claim buddy

@Syed Rigorous proof of no-signalling.

^ Assuming relativity where it assumes the hamiltonians are also independent

@Syed And this??

It makes no sense to assume the hamiltonians being independent if non localiry true

@Syed Why's that?

Explain to me, who clearly doesn't know what she's talking about, why it's an unreasonable assumption.

Show your work! A hamiltonian isn't just a word we use, it's a Hilbert-space operator.

Read the theorem by Shimony. He, like all no signalling theorems, assume that the Hamiltonian for entangled states does not have cross terms

@Syed Why did they make that assumption?

Do you know why he assumes that? He assumes that, and I quote, “but then we could violate parameter independence [no controllable signalling])” it’s a circular argument

Okay, then, write out for me a Hamiltonian that allows for FTL communication.

If that's what you're arguing, of course. It was never in question that there's a no-info superluminal link between particles.

In quantum information theory, they literally put in cross terms for the Hamiltonian. But if there’s cross terms, no signalling theorem will not work

Cite an example?

Importantly, can you also find zero reasons why cross-terms should otherwise be disallowed?

And even more importantly, can you find a physical scenario where a Hamiltonian with cross terms will actually appear? i.e. an actual construction that leads to FTL communication?

scholar.google.ca/scholar_url?url=https://arxiv.org/pdf/…

Example is in that

My point is this: you admit there’s a Superluminal connection. If there’s no information transfer, how is it doing it in your own opinion? Don’t just say “because math”. Math is just. Desorption.

"Entanglement capabilities of non–local Hamiltonians" - so you now know that cross-term Hamiltonians are inherently non-local, and you're saying "if you allow for non-local Hamiltonians of course you can achieve non-local results?"

@Syed 1) I admitted this from the start. It was in the first revision of my answer, at the very top. This tells me that you didn't actually read my answer, and that you thus were just looking for an argument to get into. 2) I've already explained this multiple times.

Your argument is akin to saying that me clapping is not communicated to the dog and yet somehow, the universe is fundamentally structured in such a way that the dog will always clap after me. It sounds ludicrous. There’s a reason Newton made fun of this idea

It is not on me to disprove every possible route of information transfer. It is on you to prove that there can be information transfer.

@Syed Again: when do we compare results?

Your argument is akin to saying that particle A is not communicating with particle B and yet somehow, the universe is fundamentally structured in such a way that the dog will always clap after me. It sounds ludicrous. There’s a reason Newton made fun of this idea

You haven't answered that yet.

Just read that and tell me that makes any sense

How is your scenario (particles communicating, we can't) at all different from mine (particles not communicating), given that they predict the exact same results?

@Syed This is precisely what QM dictates will happen, so yeah that makes perfect sense. No communication need happen for this to happen, so why assume that communication is happening?

because nothing else in the universe communicates without something being transferred through a medium. So we have antecedent evidence to prefer the former even if we can’t prove it yet

And history suggests the same

Gravity was proposed as true action at distance. But it ended up being information transferred through the gravitation waves

@Syed Except for, you know, photons moving through a space without a medium.

It’s moving through space

You’re taking the notion of medium literally

Space is not a medium. Space is a set of points.

In entanglement, according to you, nothing is moving through space either

Between the particle A to particle B

At measurement

Yes. The particles are correlated at entanglement time, and they remain correlated until measured. No movement required.

Yes, the same way people in Newton’s time thought: “the masses are correlated. They remain correlated. Nothing needs to propagate between them through space”.

And they were wrong.

Well then, what's your experimental evidence that they're not?

Good point: we eventually did get experimental evidence for gravity propagating at c. That was experimental evidence. Where's yours?

What was the experimental evidence back then proving that something was propagating between masses in space?

My argument isn’t that there is something propagating. My argument is that you can’t say that there ISNT.

@Syed Yep. It's impossible to prove a negative. Once again, Russel's teapot.

Why not just be humble and say you have no clue as to how the Superluminal connection works?

I can't prove that there isn't a medium. It's just not possible. It's also not on me to prove that there isn't one.

It's on you to prove that there is one.

Yes but the burden is on the claimant. If I make an argument against god I have the burden

Same goes for you

I am not making the positive claim that there IS a signal

You are making the claim that there isn’t

@Syed I claim that information cannot be transferred.

My evidence is mathematical proofs and simple thought experiments.

Are you claiming that information can be transferred?

If so, get off Stack Exchange right now and go write up a paper to get published. You'll be famous and obscenely rich for designing the first ansible.

and there’s no proof of that, since you haven’t shown that information cannot be transferred through space between the particles, same way people before couldn’t say informeiton wasn’t transferred between masses

@Syed Russel's teapot. It's not on me to prove that information cannot be transferred through the space between the particles (although various people have); it's on you to prove that it can be.

So, go ahead. Where's your proof that it can be?

Experimental evidence or a solid mathematical example will both work well.

You are making the claim that information isn’t propagated through space between the particles. Unless you retract that claim, the burden is on you

@Syed I have provided multiple instances of proof. I'm supporting the null hypothesis: "no information is transferred, because why would it do that?" It's on you to now prove that information can be.

If you want to say “there is no evidence that information is propagated” that’s fine. But saying that there isn’t information being propagated is a much stronger claim

@Syed I provided proofs that information can't be; you dismissed them for reasons you didn't elaborate on.

Is it really still on me?

But we have other reasons to think that the default SHOULD be that there’s something being propagated. Because nothing else in physics that involves objects being correlated to each other at long distances occurs WITHOUT a propagated force/mechanism (except correlations with local hidden variables)

Even if we don’t know how it’s propagated

@Syed What are those reasons? My models work perfectly well without anything propagating between the particles.

But I’m also fine with “we don’t know”

If every single day, you saw certain letters being written in the sky, “A” then “B” then “C” I can now model this scenario and make predictions. This would tell me NOTHING about how those letters are being formed

I didn't claim, in my original answer, that I knew how the superluminal link worked. I just claimed that you can't signal with it, answering your original question.

Similarly, you know NOTHING about how exactly this Superluminal connection remains

Yes.

Be humble and just say you don’t know

I know nothing about how the connection works.

I didn't claim to know, either.

Should I repeat my answer in here, verbatim, so that we can clear that up?

Okay let’s just leave it at that then. To me, claiming that information isn’t being transferred at all through space is not indicative of a lack of knowledge. But I rest my case now

Okay, cool. Good day to you :)

Indicative of a claim for not knowin* good day to you too!