What did Einstein mean by “spooky action at a distance”?
backreaction.blogspot.com
backreaction.blogspot.com
It's a little gem featuring interviews with a young Alain Aspect, John Bell, David Bohm, Abner Shimony, John Wheeler, & a very excited Holger Bech Nielsen. It is very accessible yet hugely informative, and somehow (with that soundtrack) enchanting.
Quantum Entanglement - Atomic Physics and Reality: https://www.youtube.com/watch?v=BFvJOZ51tmc
First of all, we don't know which color is in which envelope at the start. And revealing of one instantly determines the other physically regardless of whether it came up red or blue. So entanglement is "spooky action at a distance".
This property doesn't constitute FTL communication though since we can't encode any information this way, we don't know what the particles will reveal when measured. We just know that measuring one will affect the other particle no matter how far apart they are physically.
So I imagine Einstein meant both.
The best example I could think of to analogise it were meshed gears.
There is no messaging happening between them. When one rotates, the other rotates in the opposite direction at the same exact time because they are interlinked. They are two parts of one connected set.
That entangled particles are interlinked in this way shouldn’t be surprising. Having what to us seem to be arbitrary distances between the particles could simply mean that they’re interlinked outside of the three spatial dimensions we’re used to perceiving the universe in - but this last part is just my own understanding and I’m quite happy for someone who knows better to tell me if (and why) it’s wrong.
Isn't there? Atoms rub against atoms, electric fields interact and transfer forces. The gears communicate by touching, but it happens so fast that it looks instantaneous. This can be experimentally verified by weakening one of the teeth of one gear, and driving some load with that gear set - eventually, the weakened tooth will break off.
It would need to be, given that the gears aren’t going to reverse time and break apart into light beams just because I looked at them.
Quantum physics doesn’t fit very well into simple examples.
Being able to measure spin at arbitrary angles is the best description, but I don't know any good analogies to it, especially ones involving envelopes.
The envelope example always seem obvious.
But when particle physicists talk about the problem, it sounds like it isn't that obvious.
I think there are people who are concerned with the foundations of quantum mechanics more generally, and they might be concerned with entanglement as an emergent feature of the weirdness in the foundations they don't like, but most of the work I see these days is on interesting ways to use entanglement.
Sticking to the metapher, how do you know, that looking at the content of one envelope will _affect_ the content of the other envelope, in contrast to you _discovering_ the other envelope's content to be the other color?
Asked differently: Why do you necessitate that viewing one envelope's content _affects_ the other, rather than merely allowing to conclude the other, because some law of the universe makes it happen to be always the other color?
To me this seems really an interpretation, rather than a fact, that one can simply put there without dispute.
Since you can choose which axes you measure, there are all sorts of tricky experiments you can do (called Bell tests) to test the theory that you're just discovering a pre-existing value vs. causing collapse to those values. The pre-existing value idea is called a local hidden variable, the existence of which has been conclusively experimentally disproven.
I wrote a post on this you might find useful, explaining a Bell test called the CHSH game that computer scientists will find intuitive. All you need is your rememberance of the unit circle from high school path! https://ahelwer.ca/post/2018-12-07-chsh/
I have one note, which I hope you don't take the wrong way: I think it would be great, if you could put the slides as PDF on your page (viewable with browser's PDF.js for example), rather than on slideshare.). Then the slides you link to for understanding the braket notation would be as accessible as the original page you link to.
If no information is transmitted between the people observing the quantum particles, how is it that you can improve their "performance" at the CHSH game above 75%?
Like, what is the fundamental unit of "information"/coordination the players are extracting from their particles/qbits?
Actually, while I'm being confused, what even is a qbit? From the descriptions, it sounds like it's not just an information, where two qbits with the same vector representation are equivalent, and it's more like a physical concept. Is it a particle? Or, like, it it some sort of global variable of the universe that stores some information that is undetermined until you "collapse" the global variable?
When we talk about information being communicated we're talking about someone choosing a bit that is then somehow reproduced with some fidelity somewhere else. Quantum entanglement doesn't allow such straightfoward possibilities. Instead it offers correlations that are stronger than would be possible with purely classical means. If this answer is frustrating because it doesn't match your intuition of what communication is - welcome to quantum mechanics! You just kind of have to learn the rules of the systems and get used to them. What you can do with entanglement (quite a lot!) is more important than what is "actually" happening under the hood.
Right, I'm not the one necessitating it. That's how quantum mechanics works for entangled particles. You can read more on this if you look up "EPR paradox".
Perhaps my idea how it might happen is too much of a metaphysical one? Here is what I think:
I imagine entangled particles to be something like 2 sides of the same coin. Something we can observe in the known "world" (all the things we know about or can look at in a lab or experiments), but which has an actual character, somewhere/when, that we cannot grasp yet. Perhaps like an object in front of 2 light sources, throwing 2 shadows, and we observe the shadows, instead of the real object. But the shadows for us are all we currently can observe at our level of scientific understanding or with our technology.
It is unclear to me, which definition of locality that object would be in or not in, reading that wiki page, so I am trying to not use that word.
The problem is, how one could prove or disprove such a thing, because it is basically an "escape hatch", with which one can always say, that there is something, we do not yet see. From an "unknown object, whose shadow we can perceive" one also cannot draw many predictions, I think, so it might not be immediately useful to assume such. My guess is, that physicists stick to theories one can prove or disprove things about. Perhaps I will ask a knowledgeable coworker to explain to me, why my idea cannot be how it really is. Thanks for the pointers, I can also mention those in my questions.
I think an issue with communicating the lack of information transmission is that the statement usually fails to acknowledge two aspects:
1) We are unable to reliably force any one entangled particle to a specified state prior to measurement. ( You mention this more passively in a gp >"First of all, we don't know which color is in which envelope at the start." )
2) After measuring we have now entangled our particle to our measurement. So, if after our measurement we change the state of our particle the previously entangled particle fails to reliably correlate.
Information is transmitted; it's useful information that we are unable to communicate.
If I give you instructions saying if the envelope contains this then do this or if it contains that then do that, you can use the information from the particle's entanglement to make that decision, but because of 2) you can only use it to make that decision reliably once, and because of 1) those two outcomes will have to be equally desirable for this form of communication; making it useless. Just roll a dice.
If A and B agree upon, that B will know what A is doing in either case of discovery, then B needs only to look at their observation and will know what A's observation is (the opposite). Then B can know how A will act, because A decides what to do based on what they observe. Then B can act in a coordinated way. Even though it is only a roll of a die, it can still be helpful.
For Sci-Fi example: Some alien spaceship fleet (bare with me!) wants to attack another civilization from 2 sides across wast distances. They split up waaay before that and each keeps an entangled particle. They agree upon which observation means what detail in the first fleet's attack plan. Depending on that, the second fleet will act differently on the other side. But the first fleet only decide which of the 2 strategies to use, when they are already split up, based on the observation of the entangled particle. The second fleet has to act accordingly, or the strategy will fail.
Is this impossible? Or is this simply not seen as useful information in some specific definition?
You are adding another conditional but nested conditionals still all rely on the first.
We are getting 1 bit of data:0|1; from this entrangled pair.
Fleet1 has Strategy0 in case their measurement reads 0.
Strategy0 requires Fleet2 to act using Strategy2 for the highest probability of success.
Fleet1 also has Strategy1 in case their measurement reads 1.
If Strategy1 also requires Fleet2 to act using Strategy2 for highest probability of success then Fleet1's measurement is useless as Fleet2 can just use Strategy2 in both events.
If instead Strategy1 requires a new Strategy3, and even though you could communicate which of these strategies to choose faster than we know how to communicate that electromagnetically, our 1 bit of information is still useless because you would still have to prepare for both eventualities.
Both pairs: Strategies02 and Strategies13; would equally have to have the same probability of success because if one is favoured over another then using this technique to decide your fleet movements could result in your allowing the possibility for the measurement to order you in a strategy you know is less likely to be successful.
This is what I was trying to get at by using the word 'desirable'.
Fleet2 may appear to be waiting on Fleet1 for orders, but in fact both fleets are waiting on their orders from the first measurement.
When I watched this on YouTube yesterday, I knew that as soon as she used the sock example that someone would get salty about it without listening to the rest of what she says. She addresses this right towards the end:
"Yes, that explains the case for the socks. But in quantum mechanics, that explanation does not work. If you think that really it was decided already which spin went into which direction when they were emitted, that will not create sufficiently strong correlations. It’s just incompatible with observations."
>So I imagine Einstein meant both
I think her view is that when Einstein said "spooky action at a distance" he was referring SPECIFICALLY to the instantaneous effect of measurement on the wave function. Entanglement, then, is just an example of this where we can increase the distance in the lab to experimentally confirm the implication.
Isn't this a refrain in the history of science? Observations inspiring models that illuminate a deeper, truer representation of reality?
[Tinfoil hat warning :] Since then it's a self-reinforcing confirmation bias to avoid the obvious locality of the real world mainly because of geopolitical reasons in the 1960s. /[Tinfoil hat warning :]
The exact flaw changes from paper to paper. They are plenty of ways to get something wrong when you are not doing statistics carefully.
It often comes down to the precise definition of what the experimenter for what a measurement is.
One usual mishap is "involuntary post-sampling", by wrongfully ignoring some blips or discarding particle that don't fit the mold.
The more complex the experiment trying to close a loop-hole the more probable the bug slips in.
From a mathematician perspective, the error is "incompatible probability measure" for events, that's why probability laws don't apply.
Bell's theorem is exactly a well known mathematical theorem "Boole's inequality" which basically tells you, you are doing the math wrong when defining your measure.
I'm not sure what you mean in the first part of your comment, could you indicate specifically what probability measure is defined incorrectly (or not defined) in (e.g.) this paper?
About the link between boole's and bell's inequalities : There are tons of paper : A quick search for example https://arxiv.org/pdf/quant-ph/0406004.pdf (I just skimmed it for a few seconds but it's probably talking about the right thing)
In the paper you suggest https://arxiv.org/abs/1508.05949, there is nothing which looks like a probability definition.
Assuming the world is using continuous fields, defining the probability for what register as a discrete event like a "blip" must be done carefully, it's not a trivial thing.
Otherwise when you are taking joint probabilities and condition probability, it just tells you that those are questions you can't ask.
I'm still not sure what probability distribution (or measure) you want to be defined in that paper. Experimentalists generally don't assume any probability distribution in advance, I am not sure why they would need to in this case.
Bonferroni inequalities are also on the wikipedia page of the Boole's inequality https://en.wikipedia.org/wiki/Boole%27s_inequality
>I'm still not sure what probability distribution (or measure) you want to be defined in that paper. Experimentalists generally don't assume any probability distribution in advance, I am not sure why they would need to in this case.
That's the thing, if you try to model it correctly you realize that what you were doing was not the thing to do, and that there is just nothing to see here, apart from yourself asking the wrong question.
Take a zone of space (the detector volume), and define the discrete event "blip" as 1 if somewhere inside the detector volume at instant t0 the field value is greater than 1, or zero elsewhere.
That's all you need : this mean you just expressed an event as a conditional probability. Therefore when you have multiple such events, you are expected to encounter some Boole's/Bell type inegalities (provided that there is information conservation in your model).
Experimentalists are doing circular reasoning. By not assuming an underlying model, they don't realize that the answer they get is due to implicitly defining events as conditional probabilities which don't span a consistent Filtration_(probability_theory), then they try to ask the wrong question, getting an answer which confirm their biases.
QM is a not a model of the world, but a model of what we can observe from the world based on what we observe from the world.
Bell's inequalities tell nothing about how the world works but only tell you that your way of observing the world is wrong.
This is because Boole-type inequalities are derived just by assuming the basic rules of probability distributions, while Bell-type inequalities are derived by assuming some local hidden variable model (or similar locality assumption).
Consider the Popescu-Rorhlich (PR) box probability distribution where P(a,b | x,y) equals 1/2 if x*y = a xor b and zero otherwise.
This probability distribution explicitly breaks Bell's inequality, but it does not break any of the Bonferroni / Boole inequalities. This is precisely because although it obeys all of the axioms of probability distributions (which are the assumptions required for Bonferroni / Boole) it does not obey the extra axioms of locality that Bell's inequality requires.
I'm still not sure what your issue is with the experimental papers. You acknowledge I think that the real detectors they have in the lab actually do "blip", right? And you can take these observed "blips" and use them to compute a CHSH value?
Experimenters observe CHSH > 2 because they are likely doing something bad with probabilities : the same bad things with probabilities you need to do to violate Boole's inequalities.
The measurement process of the pairs by the detectors implicitly do some additional filtering on the hidden_state. Typically when you define what your detection threshold for registering a blip is, or what you consider is a coincident pair by filtering based upon the time of measurement.
When you try to apply Boole's inequality to something like
P( anything | measurement1, measurement2, 0< hidden_state < 1),
P( anything | measurement1, 0< hidden_state < 1),
P( anything | measurement2, 0< hidden_state < 1)
The chain rule doesn't apply the same way. Because hidden_state is not a specific value but a range of values : The joint probability is not factoring as a product of conditionals anymore.
You have some incompatible sets of events and you can observe CHSH type violation for your Boole's inequalities.
I sort of agree with this, if by "something bad" you mean not obeying the axioms of probabilities.
> Experimenters observe CHSH > 2 because they are likely doing something bad with probabilities.
I disagree with this completely. Note that the probability distribution I gave just now (which is an honest probability distribution) violates CHSH. It obtains a CHSH score of 4, indeed. I am not doing anything "bad" with my probabilities to obtain this score, I'm just providing a probability distribution that does not obey Bell's additional locality assumption.
I ask you specifically, what is "bad" about the distribution
P(a,b| x,y) = 1/2 if ab = x xor y and zero otherwise
which makes it obtain a CHSH score of 4?
You can violate CHSH by giving a non-local distribution (That's what happening with the distribution you provide).
But there is more than one way to skin a cat.
You can also violate them using the mathematical trick as I suggested above. This trick to replicate the result seems a lot more plausible than non-locality.
> not obeying the axioms of probabilities.
That's exactly what I blame the experimenters for.
By ignoring that they are conditioning on the hidden variable, they are treating what is a "conditional probability" exactly the same way as it if was a "standard probability". Which is a big no-no from the math standpoint.
Marian Kupczynski : Closing the Door on Quantum Nonlocality : https://philpapers.org/archive/KUPCTD.pdf
If there can be many outcomes, like the Many Worlds Interpretation suggests, then I think there is the possibility that the "spooky action at a distance" is a result of purely local interactions.
Notice that in the double-slit experiment, the wave function at different places interacts with itself so as to lower the probability of a photon or electron arriving at a place where it was likelier to arrive with just one slit open.
Informally speaking, that could be seen as an example of different "worlds" (i.e. different places where the photon could be observed to exist) interacting with each other locally so as to effectively lower the probability of observing the photon arriving at some place where it would be likelier to arrive had the different worlds not have interacted with each other. Taking the analogy a bit too far, this seems like if two different worlds interfere with each other so as to cancel each other out. Again, the photon/electron that was likely to arrive at some place, will not likely arrive anymore, and this is purely due to the the wave function interfering with itself.
Wouldn't that mean that there is the possibility that the observed correlations in Bell's theorem could be the result of this phenomenon and not necessarily mean that there is non-local behavior?
That is, couldn't the observed correlations be the result of the different worlds interfering with each other locally, e.g. when the light cones of the different measurements intersect each other, so that some worlds cancel each other out and we don't get to observe them, leading to the correlations that we do indeed observe?
Bell's theorem, as far as I understand, only takes into account what we can observe, but could be falsified if there are "worlds" that we cannot observe, i.e. that are temporally created but stop existing when they cancel each other out by local interactions.
Although, admittedly, I could be completely wrong because I don't understand enough of this to be sure of what I'm saying :)
Everytime I listen to somebody raffle off about determinism or the law of identity I remind them that bells theorem (there's real actual randomness) and it's corresponding no-cloning theorems proved objectively that the universe has real randomness, and that truly "cloning" an object (e.g. A=A) is literally impossible.
Sorry that reality doesn't work the way that you want homie. Bells theorem is my favorite theorem because of this level of butthurt that it instills...
Does physics have a definition for existence?
"If, without in any way disturbing a system, we can predict with certainty (i.e., with probability equal to unity) the value of a physical quantity, then there exists an element of reality corresponding to that quantity."
That's a curious definition of existence.
And now that I think about it a bit more, it seems like it's not really talking about what existence is, but rather the consequences of existence and the consequences of certain prediction. That's not quite the same as a definition of existence, is it?
It leaves that part unsaid.
To go a bit deeper in to this, it's not just saying certainly predictable properties are certainly predictable. It wants to say something else about them: that they exist. What does it mean by that?
The statement as it stands is more about certainly predictable properties than it is about existence itself.
When I said "the very value of the entangled properties does not exist locally" in my first post I meant that there is no way to predict the value (or of consistently assigning a value to the property) before performing a measurement.
After years of losing sleep over it, I like to think that entangled properties are somehow 'part of the same whole', which is independent of space-time, and that space-time is a construct that emerges from the particular way decoherence seems to choose position and momentum as preferred bases.
So, you open your envelope and set your device to measure if the sock is 0.2 red and 0.8 soft (so, either blue or soft), and you get True. If the person who got the other sock set their device to 0.8 red and 0.2 soft, the classical probability that they get True would be 0.5 I believe.
But if you perform this experiment with quantum entangled properties, you would see a greater value. Further, Bell has shown that one of 3 things must hold for quantum socks:
- either they are neither blue/red nor coarse/fluffy until the measurement; after the measurement, your sock gets some value, and the other sock implicitly gets the opposite value, but there is no real "state change" since they didn't have any state to begin with (we reject realism)
- they "tell" each other instantly in what state they were found (we reject locality)
- the fact that you were always going to receive the red sock also caused you to choose 0.2 red and 0.8 soft, so what may look like a coincidence is in fact pre-determined (superdeterminism)
Search for Wigner's friend. Relational quantum mechanics is the only logical and consistent epistemology for what all this means.
Effectively, nothing ever changes, just extra information allows for simplification of observables backed by large expressions.
The universe is inherently lazy, and it's like LISP. PG come at me!
But objective collapse due to anyone's consciousness does not solve anything - my observation of this particle still causes infinite speed effects on your particle, so the universe is anyway non-local.
There is a correlation between us, still. So it isn't like our wavefunctions are going to be radically different. We both are entangled since the Big Bang and even after that many times over as shared information exchanges between us.
In general, I believe the most obvious interpretation of consciousness is simply as a computational process, so looking at consciousness as a key to QM is incompatible with my beliefs.
Furthermore, given the classical-ness of the world we see everyday, I have huge problems believing theories like MWI or these consciousness-based ones that claim the world is entirely quantum everywhere and it's just some kind of accident that it seems so classical to us (contrast to relativity which has a very satisfying answer for why we don't notice the difference from classical mechanics).
The universe is indifferent to your persuasions. The double slit experiment has been successfully performed on large molecules of 810 atoms. Quantum mechanics is fundamentally about knowledge and information after interactions. You seem to be a physics guy but something tells me you aren't aware that every single interaction causes entanglement. Entanglement is simply a constraint on interaction products, given the input particles. It is just easier to see its effects on small objects since they are less likely to be perturbed.
I think we just don't know enough yet to choose any one interpretation. I hope that at some point we'll find a way to address the measurement problem - either finding that the classical world also behaves quantically or that there is some clear limit between them or that the quantum world behaves classically (least likely).
But until then, we're all just guessing.
Edit: 810 atoms is great, just ~6.023*10^21 more to go and we'll have something that is truly in our range of advertising.
Eraser experiments have already shown that collapse either doesn't actually happen or is reversible. It appears that all observables are just lazily evaluated nested expressions. Collapse/decoherence is just the phenomena of simplification of expressions. The expressions don't change. In the quantum eraser experiment, the erasure causes the expression to no longer be simplifiable.
This would assume that somehow the atoms in our brain work differently than the atoms anywhere else. There is nothing special about consciousness.
Honestly, the rest of your post is a bunch of mumbo jumbo, it’s difficult to see what you are trying to say.
You assume wrongly. The implication is that all wavefunctions have a corresponding consciousness. Since the universe is a nested set of wavefunctions, it's essentially all consciousness.
There is nothing special about consciousness, it's the unified field, it's all there actually is.
Honestly, the rigidity of your thinking holds you back from seeing any deeper truth.
Since humans have finite lifespans, we all develop some heuristics (probably heavily biased ones) to serve as filters for what is efficient to consider.
As such, one of my (again, heavily biased) filters are any such claims that meditation could have an outsized impact on the level of deviance/crime in the Washington DC.
" We present the published results of a National Demonstration Project-in which 4,000 advanced meditators markedly reduced violent crime in Washington, DC."
I simply don't have time to consider this as my personal biases are telling me to ignore it and that it is bad science.
Furthermore, the researcher here very frequently makes use of highly theoretical and even unproven concepts such as string theory and a particular variant of the multiple universes idea which has also not been proven. Both are presented misleadingly as concrete fact rather than assumptions made. I dislike being misled and distrust the researcher moreso because of that.
I assume your biases are quite different from mine. I assume some level of experimentation with hallucinogenic drugs may be involved? No judgement - I've just seen lots of similar appeals to philosophical interpretations of physics from other LSD users I know.
> You assume wrongly. The implication is that all wavefunctions have a corresponding consciousness. Since the universe is a nested set of wavefunctions, it's essentially all consciousness.
First, a wavefunction is a way of making sense of (some of) the concepts of quantum mechanics. It has a specific meaning, and scientists to this day argue about whether it is necessary or actually a thing.
When it is used, it is a scalar field that is used to describe the probability of some experimental result, i.e. a mathematical tool. It has no link whatsoever with consciousness, which is the result of electric signals going up and down a group of neurons bunched together.
You sound like you want to redefine “consciousness” as “existence”. In that case there is some tautological beauty in what you say, but it is not as enlightening as you seem to think it is.
> There is nothing special about consciousness, it's the unified field, it's all there actually is.
What the hell does that even mean? You use scientific-sounding words without seeming to grasp their meaning.
I mean, surrealism is fun, and metaphysics can be interesting, but don’t confuse them with a deep understanding of physical truths.
> https://youtu.be/LPhgDfT4Zpc
I need to point out that you are citing a crackpot and that there was absolutely nothing scientific in what I have seen in this video. But yeah, it probably is my mental rigidity talking.
https://en.wikipedia.org/wiki/Universal_wavefunction
> Since the universal validity of the state function description is asserted, one can regard the state functions themselves as the fundamental entities, and one can even consider the state function of the entire universe. In this sense this theory can be called the theory of the "universal wave function," since all of physics is presumed to follow from this function alone.[7]
You appeal to a trivially naive interpretation of what the wavefunction represents, yet claim that I or Hagelin are the crackpots. Don't you know that all modern science requires unobservables? Yet you want to constrain the wavefunction to being a mathematical tool for measurement only because that was its intended purpose and conceptual creation. Narrow mindset.
https://en.wikipedia.org/wiki/Unobservable
> You use scientific-sounding words without seeming to grasp their meaning.
You think you understand quantum physics when no one does. Furthermore, you don't even understand wavefunctions except by their textbook definition...
The map is not the territory. A ball is a ball and its motion is its motion, while Newton's equations of motion for that ball are something else.
While it is possible that the MWI is right and the state of the entire universe could be described by a single, universal wavefunction, that wouldn't mean that the universe is that wavefunction, anymore than Maxwell's equations are the electromagnetic field.
Now, there is an interesting question that indeed no one knows the answer to for now: is the wavefunction a direct description of a physical object, or is it just a statistical tool for predicting possible positions of the real objects (waves and particles existing in some duality)?
Also, you shouldn't forget that none of the existing interpretations of QM actually solve the measurement problem, not even MWI. Here is Sabine Hossenfelder's explanation of this [0]:
> In the many worlds interpretation, if you set up a detector for a measurement, then the detector will also split into several universes. Therefore, if you just ask “what will the detector measure”, then the answer is “The detector will measure anything that’s possible with probability 1.”
> This, of course, is not what we observe. We observe only one measurement outcome. The many worlds people explain this as follows. Of course you are not supposed to calculate the probability for each branch of the detector. Because when we say detector, we don’t mean all detector branches together. You should only evaluate the probability relative to the detector in one specific branch at a time.
> That sounds reasonable. Indeed, it is reasonable. It is just as reasonable as the measurement postulate. In fact, it is logically entirely equivalent to the measurement postulate. The measurement postulate says: Update probability at measurement to 100%. The detector definition in many worlds says: The “Detector” is by definition only the thing in one branch. Now evaluate probabilities relative to this, which gives you 100% in each branch. Same thing.
> And because it’s the same thing you already know that you cannot derive this detector definition from the Schrödinger equation. It’s not possible. What the many worlds people are now trying instead is to derive this postulate from rational choice theory. But of course that brings back in macroscopic terms, like actors who make decisions and so on. In other words, this reference to knowledge is equally in conflict with reductionism as is the Copenhagen interpretation.
[0] http://backreaction.blogspot.com/2019/09/the-trouble-with-ma...
The wavefunction of the universe is the state of it, and all conscious observers _ever_ do, is measure states. Interaction is all there is, just relationships. The state is isomorphic to the reality. The only difference is the reality has some process running on it, to advance the arrow of time.
This is not confusing the map for the territory. Every physicist you ask will tell you that a particle is the matrix it is represented by. Now, we may not have those matrixes fully complete or accurate, but the backing of reality IS information. And no, information and numbers do not have to have a reality onto themselves - they are just the medium of comparison, otherwise any description is impossible. All descriptions that humans use are metaphors based on past experience.
That just begs the question of what consciousness actually is. You can define consciousness as being the wave function, but then you still have to actually check if what 'consciousness' colloquially means has any resemblance to that.
For example, when you tell me something is conscious, I expect that I can teach that thing certain things, like how to sing or how to fetch. Since a photon has a wavefunction, by your definition I would expect to be able to teach a photon to do things.
Similarly, I expect conscious things to be able to interact with the world and have feelings about it. Do you beleive a photon admires an electron more than a proton, or anything similar?
Until you can show any experiments where anything that is known to be described by a wavefunction is shown to have all of the properties we associate with the word 'consciousness' in everyday usage, your assertion that all wavefunctions have a corresponding 'consciousness' doesn't really mean anything. I could just as easily say that all wavefunctions have an associated music, and that music is all there actually is. It's a definition, so it's not wrong, but it's not illuminating.
The possible futures for a photon, given the laws of physics, are much simpler than for you or I. Its wavefunction is known. The usual (classical) Maxwell field is the quantum wave function for a single photon.
> Similarly, I expect conscious things to be able to interact with the world and have feelings about it. Do you beleive a photon admires an electron more than a proton, or anything similar?
You are confusing consciousness with reactiveness. Deterministic rules can cause reactions. Your refrigerator for example, reacts to temperature changes. It however, is not exercising free will or any kind of quantum randomness to do so.
> Until you can show any experiments where anything that is known to be described by a wavefunction is shown to have all of the properties we associate with the word 'consciousness' in everyday usage, your assertion that all wavefunctions have a corresponding 'consciousness' doesn't really mean anything. I could just as easily say that all wavefunctions have an associated music, and that music is all there actually is. It's a definition, so it's not wrong, but it's not illuminating.
There is no rule-based construct for random number generation except for PRNG[1]. It follows that, if true randomness is exhibited by the universe, one that is not generated by rules, then it must be the leftover ingredient. Consciousness is the only leftover ingredient. Everything else we know about physics is deterministic and rule-based. Now, you know very well, things like this are likely not able to be proven given the hard consciousness problem and the other proximal issues. So I'm making an argument. Some things in life are arguments, not proofs. Like political views. Get used to it instead of being cliche and resorting to Newton's Flaming Laser Sword.
[1] https://en.wikipedia.org/wiki/Pseudorandom_number_generator
Now, you could say that consciousness is a quantity that humans possess a lot of, while photons possess a tiny little amount of, like the Integrated Information Theory people claim. But there is no proof (or even indication, in my opinion) that the IIT 'consciousness' actually captures what we mean by human consciousness.
> It follows that, if true randomness is exhibited by the universe, one that is not generated by rules, then it must be the leftover ingredient. Consciousness is the only leftover ingredient. Everything else we know about physics is deterministic and rule-based.
Randomness is not necessarily a part of QM. For example, in MWI, there is no randomness in the universe - it is perfectly deterministic, as every state of the wave function is realized. In pilot-wave theory, the only randomness is classical - errors in knowing the initial state with absolute precision.
Even if CI or other fundamental randomness interpretations of QM are correct, there is no obvious connection between consciousness and randomness. There are other unknowns in the universe - you could just as easily say that dark matter is consciousness or dark matter is the source of randomness, or dark energy etc.
And only since you briefly mentioned it, free will (as in conscious choice affecting the next state of the universe) is incompatible with QM, as QM is a linear theory, where the next state is uniquely determined by the previous state, especially in MWI.
Rules are not a source of real randomness and there is a consensus among physicists that quantum randomness is actually true randomness. Even if you put the source of randomness into some other thing like dark matter, you cannot explain its construct..because all you have is rules. You must forfeit and concede to nature a black box RNG library. This is clearly ludicrous. The more obvious and consistent view is that conscious beings (that feel they have willful decisions) are the manifestation of nature's RNG for quantum mechanics
IIT is an entirely different beast related to self attention, a different kind of definition for consciousness, that has little to do with will. Unrelated...
QM is unitary, but it is one to many. It's a giant branching rooted tree. This is irrelevant, it is not deterministic like general relativity.
Please step back in the element. These refutations are becoming exhausting.
In CI there is indeed true randomness, since only one 'branch' of the wavefunction is actually happening.
Say you are going to flip a quantum coin. Before you flip it, given MWI, you know that there will be two copies of you, each experiencing one of the outcomes. After you flip it, one copy sees tails, the other heads. Each copy is perfectly identical except for the new observation. Each may ask itself 'what were the chances that I am seeing heads/tails?', and with MWI in mind, they should answer 1: the chance that the copy-that-sees-heads sees heads is 1, and same for copy-who-sees-tails seeing tails, since there is no other way to identify them as separate entities.
This also corresponds to the mathematics of QM: if you want to give proper predictions, you need to 'update' the wavefunciton to have value 1 for the observed outcome and value 0 for any other outcome. Doing that for 'your branch' is precisely how MWI works.
Taking your example of the socks, with their varying and inverse properties, why do we need "spooky action at a distance" to describe the fact that one can test the properties of their local sock and therefore know the properties of the distant, entangled sock? If we now that the total value of each property will equal 1 (as in your case) then measuring the local sock will tell us the values of the distant sock.
I am not sure what I am missing, only that I am missing something here.
Fundamentally the answer is that you can't break a Bell inequality with the socks, but you can with some entangled particles.
The socks analogy kinda fails to capture the interesting stuff here, and I'm not sure if any classical analogy really works, but I'm gonna try to summarise the setup.
You have two boxes (imagine they're in different rooms, being operated by different people), call them A and B. Each Box allows you to input a single bit, we'll call A's bit x and B's bit y. Each box outputs a single bit in response to the bit you give it, call the bit output by A a, and the bit output by B b. You can then form a probability distribution
P(a,b | x, y)
The joint probability distribution of a and b conditioned on the inputs x and y. Quantum mechanics predicts a particular form for this distribution, and in particular it does not depend where the boxes are, and when (in which order) the bits are input. Based on special relativity therefore we would expect that the distribution of a conditioned on x should be independent of the distribution of b conditioned on y. In maths this means that
P(a,b | x, y) = sum_i P(i) P(a|x, i) P(b|y,i)
Basically we're allowing the output bits to depend on some shared randomness P(i), but we're not allowing a to depend on y and we're not allowing b to depend on x. This is reasonable because we have the freedom to put x in a after we receive b from y, or vice-versa, or have them separated by arbitrary amounts of space, or whatever we like.
It turns out that the probability distribution P(a,b|x,y) that quantum mechanics predicts is not of this form. The probability distributions we observe in reality, when we actually do the experiment are also not of this form. This seems to mean that somehow, even if they're separated by arbitrary amounts of space, or done in whatever order you like, or whatever the output bit a does somehow depend on what input you give box B and vice-versa.
https://simple.m.wikipedia.org/wiki/Bell%27s_theorem
The book it's taken from is excellent
Basically what is happening is in some ways similar to what gives quantum computing its extra power compared to classical computers: as far as we can tell, quantities at the microscopic level are in fact complex numbers, and so combine in ways that give different values from the real-valued quantities we are used to from the classical world.
Einstein Podolsky and Rosen put down the scientific and theoretical foundation for testing enganglement in Quantum Mechanics.
Treating it like just a horse race where Einstein was "wrong" is missing the contribution they made by designing the experiment (refined by Bell and tested by Aspect).
What is interesting is that Bohr was "correct" but his contribution is mostly a bunch of untestable philosophical nonsense.
The better contribution to science here is Einstein even though nature decided that his hunch was wrong.
And there's a lesson in here somewhere about human nature and how we value people who just make lucky guesses that pay out and we call people who change their mind after more information comes in "flip-floppers".
It seems to me that it's fairly easy to explain why one particle correlates to the other. Both of their properties are set before they are separated. We just didn't measure those properties beforehand.
I've read and watched a lot of quantum physics on youtube. This kind of refusal is always elusive, as in nobody has an experiment to negate this explanation (or maybe I miss it).
Wave-particle duality is another one that doesn't feel real, especially when we fire one electron and we say "electron interfere with itself". It seems we think of it as a wave simply because the electron is too small for us to see. And that's it. Somehow we come up with this convoluted explanation with catchy name "wave-particle duality".
This one is also elusive. Is there an experiment that refuses this explanation of how wave-particle duality isn't real?
She is the kind of specialist that we expected to find more of in the early days of the internet: deep knowledge and an interest in and capability for explaining things clearly to non-experts. We need more people like her, if only to be able to evaluate if she is right or not in some key questions (like her opposition to still more powerful particle accelerators).
In this case I find her explanation of Einstein's famous phrase regarding quantum mechanics quite rational, which is a novel experience for me when it comes to quantum mechanics.
The important difference between now and when the answer was written is that she has given her own alternatives: she believes that only theories that resolve an explicit contradiction or open problem in current physics should be considered, such as quantum gravity or dark matter or the measurement problem; while theories that simply fix 'ugliness' should be ignored, such as grand unification.
Furthermore, she believes that theories with open parameters whose range exceeds possible near future possible colliders should not be tested, even if the lower bounds on the parameter could be testable - this is true for supersimmetry or WIMPs. Since ruling out supersimmetry entirely requires a planet-sized accelerator, there's no reason to keep building slightly larger ones just in case.
Finally, she makes a concrete recommendation: shifting focus to astronomy as a better way to observe high energy particle physics occurring in the universe, investing in much more advanced telescopes instead of bigger particle colliders.
Each starlink launch makes this task harder and more expensive. They have chosen a military satellite grid over scientific research :(
People can have strong opinions and still present the issue fairly. I'd even go as far to say, you're probably not a very good expert if every view you have exactly mirrors the status quo.
If you advocate that A (for example, a large telescope) should be funded instead of B (for example, a particle collider), because you estimate A to be more fruitful, it's not a negative view. It's just a view.
You must be pretty strongly in the particle collider camp, if you view funding telescopes as a negative view.
“Distance” is still a factor in fields hence locality, the action isn’t instantaneous and is governed by the universal speed limit and the amplitude is also affected by distance.
Entanglement works instantly and regardless of distance hence the spooky part.
Sean Carrol gave a talk about his new book and his claim is that quantum mechanics is pretty straightforward, and all the spooky weirdness is only needed if you try to ignore the implication that the data supports the-many world interpretation.
i.e. similar to the sock example given, when you open the envelope you find out what universe you are in, the blue sock or red sock universe and that tells you information about the other sock in your universe. But another you is finding the other color sock in a different universe.
https://www.quantamagazine.org/why-the-many-worlds-interpret...
He appears to be saying it can't be true because it would make life/and or the concept of self meaningless.
Whereas I would say that a theory that suggests we are meaningless temporary blips in an infinite universe is probably a much greater indication that it is true than otherwise.
I'm not a big fan of the article, it mostly just defines self in a nonsense way and then treats it as a contradiction with MWI despite also laying out more sensible answers.