Wait a minute, are you saying that all observers in all frames would agree that instantaneous transfer would occur simultaneously?
I don’t think so.
It’s a question, not a statement. My question (which somehow came out of the mouth of Indistinguishable 
) is: What does instantaneously mean if not that the second event occurs simultaneously with the first?
That’s not an attempt to imply something. It’s a question about the meanings of instantaneously and simultaneously.
The concepts of things like “observers” and “frames of reference” (in spacetime) and perhaps even “instantaneous transfer” are mostly bound up within the paradigm of relativity.
In the quantum models, if a measurement for time goes to zero (or infinity) it’s sort of another way of saying our paradigms are incomplete (whether the quantum paradigm or the relativity paradigm).
If what you are asking is, “Does disentanglement take any time?”, the answer is, “no.” None. Two entangled particles a bazillion kilometers apart are entangled or disentangled. Those are the only two states. There is no time duration (for any observer anywhere etc etc) during which one particle has assumed a spin and its entangled partner’s spin is still indeterminate.
Hence the whole idea of spooky action at a distance. It’s not spooky because information is transferred faster than the speed of light. Its spooky because there is no time involved whatsoever. It is not, for instance, analagous to a thought experiment in the relativity world where a mass disappears but its remote gravitational effects remain in place until an amount of time passes equivalent to the duration of time it would take for the last wave to cross that distance.
I’m probably just having some mental blockage, but what could Bob actually do, provided there was no Bell inequality violation, to influence the statistics on Alice’s end? In other words, how was FTL communication to happen in the first place? I mean, measuring a pair of entangled particles along the same axis isn’t actually any different than writing ‘1’ and ‘0’ on two pieces of paper, putting them in sealed envelopes and opening them far from each other – the only information you get is which one you ended up with, the knowledge about the other then follows from inference (and is completely independent of whether or not the other envelope has actually been opened). That’s not a viable way to transmit information. Could Alice somehow infer whether or not Bob made a measurement? It seems like there should be something there, but I’m just not getting it right now…
The interval between two events that are spatially separated, but occur at the same time is spacelike, so they cannot be causally related. Therfore I would say that SR simply does not apply here, and leave it like that.
Even info of that type would require an additional slower than light communication.
Absolutely nothing.
Okay, but am I remembering incorrectly that spatial and temporal separation are frame relative?
I think my question may be getting lost here. Let me recap.
I asked what it means to say that the effect we’re discussing occurs “simultaneously.” I asked because simultanaity is frame relative, so I’m wondering from what frame the two things are supposed to be happening “simultaneously.”
You replied that it’s not simultaneous, it’s instantaneous.
I replied by saying I don’t know what it means for one thing to follow “instantaneously” after another unless it means for them to happen simultaneously. In other words, as far as I know, instantanaity is as frame-relevant as simultanaity.
You replied by pointing out that when things happen at the same time in two different places, their separation is spacelike, and so there can be no causal relationships between them.
But again, this doesn’t address my question because (if I understand correctly) whether things are separated by a timelike or spacelike interval is itself frame relative, and my whole question has been all along what frame of reference is being used to say that the two effects in question have this particular sort of interval between them.
In other words, as far as I can tell, the following are three ways to ask the same question:
“In what frame of reference are they simultaneous?”
“In what frame of reference does one follow instantaneously after the other?”
“In what frame of reference is their separation spacelike and not timelike?”
Now I suspect I am wrong, and that the third question is not relevantly the same as the other two questions. I suspect this because I suspect–but do not know–that things’ being causally related to each other or not is not frame-relative. But if that’s so, there’s something I don’t understand. If simultanaity is frame-relative, why isn’t spacelike separation also frame-relative?
-FrL-
You understand perfectly fine. You cannot use entanglement as an information channel. There is no way to transmit information over it.
How much the separation is is relative. Whether it’s spatial or temporal is not.
I tend to think of the situation as a single state, rather than two entangled states. One state where the spins of the two particles are opposite. So it’s not “I’ve measured the spin of this particle, so I know what the spin of that particle is.”, so much as “I’ve measured the state of the system.” The system in this case is macroscopically large. This suggests (to me, at least) that while the situation may be well-defined before and after the interaction, the situation during the transition (0.06 mlliseconds for the case in Dervorin’s link, where the state is 18 km across, 0.48 milliseconds in Pochacco’s) may not be as well defined. I can’t actually read the links apart from the previews. By the time the results from the two locations are compared, you’re in the post-transition time.
Okay then! Is it safe to say that talk of the effect’s “simultanaity” is just loose talk for the fact that there is a spacelike but not timelike separation between the two relevant locations in spacetime?*
Such that it’s not important so much that anything is happening “at the same time” but rather just that they’re happening at times indicating a lack of causal connection? Outside each others’ light cones in other words (I take it)?
-FrL-
*I used that awkward prhase “relevant locations in spacetime” to avoid running afoul of Indistinguishable’s point that it might be a mistake to even refer to what’s happening as “events” in the first place.
It doesn’t make sense to me to think of two (quantum paradigm) entangled particles existing in separate (relativity paradigm) light cones. You can describe each of the entangled particles within a relativity paradigm, but quantum mechanics does not describe “them” that way; entangled particles are a single wave function, so to speak. A light cone needs to have time as one of the elements. A wave function describing two entangled particles does not. The collapse of this waveform when the particle is measured occurs at single moment which disentangles the two particles. Now they can go on their way as separate entities with a description in a spacetime paradigm that gives them each their own light cone, if you like.
Yes, I’m clear on that, however I was wondering whether or not there actually ever was serious speculation that there could be, and if a mechanism for that had been proposed (since the whole scheme of just bringing your packed entangled particle just seems so self-defeating, as has been illustrated a couple of times in this thread – you don’t need any deep investigations into quantum mechanics to find that it’s not a viable route for information transfer).
New questions:
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Can I entangle three or more particles?
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Can different types of particles be entangled?
I think the reason you’re not getting answers is that you’re applying special relativistic terms to a system that is outside the scope of SR.
For instance how can the particles be spacelike separated when no matter how far apart they are they are always causally related?
I suppose you could say the events (or whatever) are simultaneous and instantaneous anytime their momentum vectors are equal and opposite. But in this month’s Scientific American there’s a 9 page article on this very subject, and they use the phrase “absolute simultaneity.” I don’t know what they mean by this, and it makes leery that any I say could be completely wrong.