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How Bell’s Theorem proved ‘spooky action at a distance’ is real

quantamagazine.org

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Re: How Bell’s Theorem proved ‘spooky action at a distance’ is real

#341

Post by tines »

mannerheim wrote: post #266
tines wrote: post #263

Earlier quoted context omitted.

So is it true that there are multiple properties of a particle---such as location, position, and maybe its spin---that are all described as wave functions, and therefore they can all be entangled? Can anything that is described by a wave function be entangled?

Since position and momentum (assuming that's what you meant, since you said location and position which are synonyms) have this sort of dual relationship, I don't think it makes sense to talk about entanglement with respect to them - they intrinsically have to be related to each other, and the position state (i.e., function) a particle is in fully determines its momentum state. But it is possible to imagine usually u…

> Since position and momentum (assuming that's what you meant, since you said location and position which are synonyms)

Yep, sorry, artifact of the editing process.

> they intrinsically have to be related to each other, and the position state (i.e., function) a particle is in fully determines its momentum state.

Sure, but the momentum doesn't determine the position (due to the constant of integration) so you can have two particles with the same momentum functions and different locations, and that leads to my next question...

> Usually when discussing entanglement, though, we're talking about 'distinct'* particles.

That's what I actually meant to ask but didn't phrase clearly: since position and momentum are described by wave functions, can you entangle the positions of two particles? or entangle their momentum?

Re: How Bell’s Theorem proved ‘spooky action at a distance’ is real

#342

Post by naasking »

GoblinSlayer wrote: post #295
naasking wrote: post #158

Earlier quoted context omitted.

> Of the 3 assertions in the abstract, the obviously false one is #2: "Any posthuman civilization is extremely unlikely to run a significant number of simulations of their evolutionary history". When you realize that running a simulation of the universe requires more processing power than is available in the universe, this is very obviously false. I think you've expressed a number of confusions. First, I think you co…

When the simulator shows a previously unseen object, it must first simulate all its history accounting for all effects to ensure that the shown state is legit and doesn't expose the conspiracy. This state should also account for all future investigations. The easiest way to achieve this is to run a precise simulation, so it doesn't save any resources.

> When the simulator shows a previously unseen object, it must first simulate all its history accounting for all effects to ensure that the shown state is legit and doesn't expose the conspiracy

The simulation only needs to produce observations that are consistent with the knowledge of the first observer. Sometimes bit even that, as I describe in the blog post, because eyewitness testimony is known to be quite unreliable.

I'm not sure what sort of history you're thinking of specifically.

Re: How Bell’s Theorem proved ‘spooky action at a distance’ is real

#343

Post by naasking »

TheRealNGenius wrote: post #288
naasking wrote: post #126

Earlier quoted context omitted.

One is an assertion with no logic to justify it, the other is an assertion with a somewhat persuasive argument justifying it [1]. They are simply incomparable. [1] https://www.simulation-argument.com/simulation.html

Just realized you linked to an article by Nick Bostrom, apparently the same guy who posits the Fable of the Dragon Tyrant. Seems in general to hold opinions in contradiction with mine.

The simulation argument is definitely true, in the sense that one of the outcomes Bostrom describes must be true. I don't think he takes a position on which outcome is true, so I'm not sure what there is to disagree with there.

As for aging and life extension, I honestly don't understand how anyone could reasonably think we shouldn't stop or reverse aging.

Re: How Bell’s Theorem proved ‘spooky action at a distance’ is real

#344

Post by gus_massa »

lisper wrote: post #198
gus_massa wrote: post #189

Earlier quoted context omitted.

I have at least 8 Physicist that I email/zoom regularly (at least twice per month). I also have half a degree in Physics, with at least 2 courses of Quantum Mechanics (all the advanced courses also use QM, but there are 2 courses only about QM). [I also have a degree and a PhD in Math, but it's not too relevant here.] Anyway, I'll read the article thoughtfully and write a long comment tomorrow. Can you take a look to…

Sure. Just to be clear, the part you are wrong about is this: > If you only have a single member of the pair, then you will see the same interference pattern in a double slit experiment than with a not-entangled particle. This bit: > It doesn't matter if the other particle has collided with a brick, went thru a double slit experiment, went thru a bad double slit experiment, or is flying to Andromeda. is correct. Also…

From the last part of 4.2

> Here's how it works. We send a pair of EPR photons through a pair of two-slit apparati each of which has a polarization rotator on one of the slits. On one side of the apparatus (side A) we install a polarization filter which filters out interference on that side and makes it visible. We can filter out interference on the other side (side B) of the apparatus as follows: on side A we keep a record of which photons passed through the filter and which were reflected. On side B we keep a record of where each photon landed on the screen. We then take these two records and combine them: for each photon that was passed through the filter on side A, we take the corresponding photon on side B and note where it landed on the screen. The end result is a (visible) interference pattern. It was there all along, but the only way we can filter it out so we can see it is to combine information from both sides of the experiment. And that is the last nail in the coffin of superluminal communication via entangled photons.

Let's suppose you are in lab B and measure where the photons hit the screen. There are no visible interference patters. But just before you call to lab A, it's is nuked from orbit.

Now, you are unsure if the people that was generating the photons were sending pairs of entangled photons to A and B, or they were just sending pairs of normal photons.

Can you look at the data you collected in B and discover what the people in the generator were doing?

Now imagine the same experiment with a rebuild lab A', but you remove the polarization rotator. Now you see the interference pattern. And A' gets nuked again. Can you look at the data you collected in B and discover what the people in the generator were doing?

---

I understand that you can take a plane and collect all the pieces of A and A' are reconstruct them, after all Classic Mechanics and Quantum Mechanics without the measurement rule are reversible, so it's theoretically possible, but very impractical.

I think this discussed in section 5. For the measurement problem, I prefer the something-something-decoherence solution. I call it something-something-decoherence because there are still a lot of work to be done before it's clear if it's the correct solution.

---

About the experiment in 4.2:

I'm 99% sure after adding the polarizer at 45° there will not be interference. You can split the polarizer into two smaller polarizers with the same angle, one for each slit. The exchange the order of the rotator+polarizer in one slit to polarizer+rotator. Note that after the exchange, the new polarizer must be rotated 90°, so it's polarizer at "-45°". Now the first thing in one slit is a polarizer at "+45°" and the other is at "-45°", so they will select orthogonal states and not get interference even after rotating one of them.

I think this can be fixed using a quarter-wave plate, but the calculation is slightly more complicated.

[Sorry for the delay.]

Re: How Bell’s Theorem proved ‘spooky action at a distance’ is real

#345

Post by mannerheim »

tines wrote: post #341
mannerheim wrote: post #266

Earlier quoted context omitted.

Since position and momentum (assuming that's what you meant, since you said location and position which are synonyms) have this sort of dual relationship, I don't think it makes sense to talk about entanglement with respect to them - they intrinsically have to be related to each other, and the position state (i.e., function) a particle is in fully determines its momentum state. But it is possible to imagine usually u…

> Since position and momentum (assuming that's what you meant, since you said location and position which are synonyms) Yep, sorry, artifact of the editing process. > they intrinsically have to be related to each other, and the position state (i.e., function) a particle is in fully determines its momentum state. Sure, but the momentum doesn't determine the position (due to the constant of integration) so you can have…

> Sure, but the momentum doesn't determine the position (due to the constant of integration) so you can have two particles with the same momentum functions and different locations, and that leads to my next question...

There's no constant of integration since the integral will be over all of space (or momentum space).

> That's what I actually meant to ask but didn't phrase clearly: since position and momentum are described by wave functions, can you entangle the positions of two particles? or entangle their momentum?

Certainly! I couldn't think of any examples of how it might occur, but I googled it and found an answer on Quora that seems to be correct: https://www.quora.com/In-quantum-mechanics-how-do-I-comprehe...

Re: How Bell’s Theorem proved ‘spooky action at a distance’ is real

#346

Post by GoblinSlayer »

tsimionescu wrote: post #340
GoblinSlayer wrote: post #339

Earlier quoted context omitted.

>Valid solutions to the Schrodinger equation give you the wave function amplitudes in multiple places; the particles in these places can interact with each other still, even if they are 'the same particle'. I suppose it's destructive interference. It's qualitatively interesting, but its observation is complicated by orthogonal states: when you multiply orthogonal states you get zero. If you can thoroughly dismantle t…

> MWI derives it from the Schrodinger equation. Observation is experience of the observer and can be calculated. Unless you assume that the observer is supernatural and is thus unknowable. This posits the notion of an observer that only observes one outcome, whereas the SE predicts that an observer will observe several different outcomes with different amplitudes. The MWI is postulating that we should only look at ea…

The result of calculation of the state of observer is linear evolution: the state of observer splits and entangles with the observed state and each part observes the respective outcome. Ironically Copenhagen gave the same result for Schrodinger's cat experiment: even before measurement it's known what states are in superposition and those states are "dead" and "alive", and it's still known without measurement too.

>that the number of observers that observe one outcome is proportional to the wave function amplitude of that outcome

If you mean the number, the norm of each state of observer that observes the respective outcome can be calculated. The statistics over the outcomes can be calculated too.

Re: How Bell’s Theorem proved ‘spooky action at a distance’ is real

#347

Post by GoblinSlayer »

naasking wrote: post #342
GoblinSlayer wrote: post #295

Earlier quoted context omitted.

When the simulator shows a previously unseen object, it must first simulate all its history accounting for all effects to ensure that the shown state is legit and doesn't expose the conspiracy. This state should also account for all future investigations. The easiest way to achieve this is to run a precise simulation, so it doesn't save any resources.

> When the simulator shows a previously unseen object, it must first simulate all its history accounting for all effects to ensure that the shown state is legit and doesn't expose the conspiracy The simulation only needs to produce observations that are consistent with the knowledge of the first observer. Sometimes bit even that, as I describe in the blog post, because eyewitness testimony is known to be quite unreli…

Existence of Neptune was conjectured before it was observed, the testimony came from instruments. If such consistency with contemporary observers was used, scientific revolutions wouldn't happen as observers would never observe what contradicts their knowledge.

Re: How Bell’s Theorem proved ‘spooky action at a distance’ is real

#348

Post by naasking »

GoblinSlayer wrote: post #347
naasking wrote: post #342

Earlier quoted context omitted.

> When the simulator shows a previously unseen object, it must first simulate all its history accounting for all effects to ensure that the shown state is legit and doesn't expose the conspiracy The simulation only needs to produce observations that are consistent with the knowledge of the first observer. Sometimes bit even that, as I describe in the blog post, because eyewitness testimony is known to be quite unreli…

Existence of Neptune was conjectured before it was observed, the testimony came from instruments. If such consistency with contemporary observers was used, scientific revolutions wouldn't happen as observers would never observe what contradicts their knowledge.

I agree, there are necessarily some background facts that must be consistent with the environment. Science might eventually be able to trace the trajectory of the asteroid that killed off the dinosaurs, but that doesn't necessarily mean you would need to simulate every asteroid in the solar system since its initial formation.

The amount of information science could infer on many questions is strictly bounded and in those cases we could only reason stochastically. The data presented at time of first observation can then be generated randomly from the set of answers consistent with what's already known.

Re: How Bell’s Theorem proved ‘spooky action at a distance’ is real

#349

Post by steve76 »

Particles are anything with a discrete start and an end. The heat required per frequency of light emission has a discrete start and end, explained by statistical mechanics. That's a particle, even though it's very abstract and ephemeral. A material object emits light which will expand the size of the universe if unimpeded. With no discrete start and end, although very minor and subtle, it's not a particle despite the object's tangible concrete existence.

Nature's internals have no mind. They are overwhelmed by the mighty surroundings and always redlining, pushing themselves to the limit. Need an electron? Nature looks all around, not just the nearest bonded atom. That's magnetism. Nature also takes the easiest path. Using it's own internals as a medium of interaction makes things easier. That's electromagnetic radiation.

We're dealing with a vast ocean of the medium of spacetime, not little building blocks of matter. In terms of (space + relative clocks) EM radiation travelling through empty space has internals of it's own. Electricity will repel or attract the entire thing. No further electromagnetism with that empty space itself. But magnetism, it gets to interact again, take an easier route using it's own internals as the medium of interaction. If you want to entangle an electron, make it so interacting with the internals of one interacts with another.

To exist, something has to give some resistance to surrounding interactions. If it happened immediately, it's just the surroundings. That's how we get the speed of light and the discrete nature of light frequencies. Besides electromagnetism, there's other interactions. Mass, as in nuclear decay, or triple pole "color" charge. Simulations and holograms mean that resistance to interaction will be much more simpler that the internals. Black holes do this. They're just one big 2D dot. Things that fall into them are crunched up on the surface.

Bell's Theorem is like measuring from the inside of a spinning coin that's growing, and stopping it. That's where Bell's Theorem, and the speed of light has more to gain. Think of a golf ball. Each dimple connects through the center. Perhaps instead of going through the center, it was easier to go on the surface, and let the center work itself out:

Why fight it? It's awesome. I think of plasma applications of the sun. That star orbits a black hole which can and does zap electrons into existence from empty space by crunching up a positron of a pair. What if we get good enough at that things stop looking like electrons but look like distant stars? Would that be a drive that warps the space time around our solar system, and suddenly the universe is much more smaller.

Re: How Bell’s Theorem proved ‘spooky action at a distance’ is real

#350

Post by archibaldJ »

lazide wrote: post #154
archibaldJ wrote: post #94

Earlier quoted context omitted.

But aren’t these “informations” just representations of (something abstract) reflected in a bunch of quantum states of your neurons? And we humans decide there are homomorphisms between mine and yours and thus they are representing the “same informations”. But really they were fundamentally different. There are no copying. Only some kind of lossy compression mimicking.

At that point you would need to decide what ‘copying’ is, exactly. Making a terrible VHS recording of a TV show would still be considered copying by most, even if none of the relative pixels ever matched.

The difference is that we can agree upon a set of measurements and a procedure for comparison (eg using difference of Gaussians) to determine how much of “copy” the recorded is to the original. We can repeatedly conduct this experiment (copy->measure->compare) and with high confidence we’d obtain a numerical value that can act as a “proof” it is a “copy”.

My argument is that not only that we do not know a way to conduct such category of copy->measure->compare experiments for human subjects, even with advancement in BCI, etc, it is perhaps impossible to conduct such experiment due to some nature of consciousness that we do not yet understand concerning “information”.

I used the word “mimicking” earlier as apparently when concerning “information” with humans, a (somewhat) “conscious” act has to be performed for the whole phenomenology to be interpreted as that of “copying”. We are encoding “information” in an extremely none-“traditional” way as information is studied and made sense of in computer science.

Similarly, the notion of “semantics” opens up two categorically different sets of paths for inquisition in programming language theory vs linguistics. There is something mysterious and trippy about what “meaning” and “information” really are (eg in regards to qualia).

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