joigus

As Markus says, all of physics is local. Why it is local is a mystery. Whether it is local is not.

Interesting. +1 People have been thinking about alternatives to complex formulations of QM for ages. I think Schrödinger himself initially thought that the presence of complex numbers in his equation might point to some flaw in his argument. There's always the trivial possibility of replacing the number 1 by the 2x2-dim identity matrix, the number i by a 2x2-dim antisymmetric matrix with determinant 1, and say something with philosophical undertones like "oh, the number i doesn't exist; it's just a 2x2 matrix!"

Sum of complex numbers can be implemented by 2-vectors. But product of complex numbers cannot. Product of complex numbers is equivalent to inner product (real part) and vector product (imaginary part). So their algebraic properties package more than ordinary 2-vectors. You can, of course, define special operations for 2-vectors that replicate all the properties of complex numbers. You can also do it with matrices, but in the end you would be doing the same thing.

Yes. There was something: the quantum state. It had all the correlations packed in. So it's not really saying anything about locality. Understood? Let me guess: No. Not necessary, not because of what you say, but because you don't need to explain it to me --I did a seminar on it in 1996-- or to Swansont, or to anybody else here. Physicists have been using PDC for a long time, and Bell already mentions it in his work. The key to its workings is non-linear crystals. The word spontaneous is not necessary, as it involves LASERs, and inherits the S from "spontaneous emission of radiation." The "spontaneous" part of it, certainly, doesn't add anything significant to the discussion of locality. You keep scavenging for words that seem to suggest non-locality is a fact, which is what you wish to be true. And it's not.

(My emphasis in bold) Yes. Another thing that bothers me is that sometimes it's a transaction or handshake --TIQM--; while other times it's the collapse of the quantum state --Copenhagen. One would think it's one or the other. But, as I said before, let them clean their own house.

I think it is. Besides, Heraclitus' is much less anthropocentric.

If that's your argument, it's as good as saying that the description of an angel consists in that it's defined as a single being of pure grace. This is a non-argument. You have no experimental basis for your FTL signal, nor theoretical description of it. (my emphasis in bold) Wrong. The spatial part of the state propagating to the left is a quantum superposition (up)1(down)2-(down)1(up)2, and the spatial part of the state propagating to the right is too. What do you mean spontaneous? You mean parametric down conversion of photons? It's essentially the same case we've been discussing all the time. Eise is reminding you that none of your points are new. We've visited them before. But every time you make a new comment, I find more and more ways in which it's obvious you totally misunderstand both the facts, and the formalism of quantum mechanics. There is no such a thing as "the identity of a particle" in quantum mechanics. The state is undetermined in the particle indices. There is no such thing as "spontaneous down conversion." Etc. And you haven't "described" the signal yet. You've just given it a fancy name.

Unfortunately, no. I did Latin and French. But as soon as I went to university, I started spending every waking hour learning English. Later I tried to learn some German and Japanese, but I was too old by then to make them stick. In English I'm quite fluent when writing and speaking, and have no accent, which sometimes I miss, as accents are often regarded as "delightfully peculiar." My English is some kind of mix between American and British. Yes, Heraclitus' "everything flows and nothing stands still" is a nice summary of it all. Isn't it? You take a bunch of phrases from the Greeks --the best ones, the scientists, the skeptics--, and all else looks like just adding details to the picture: Everything is made of atoms. Everything changes...

Subtle language barrier there. I'm not a native English speaker, and I obviously missed the nuance. Sorry.

Mathematical illiteracy is one of the best chances big oligopolies have to make bundles of money with no substance behind their claims. It's not beyond belief that some big companies will try to have you think they're giving money away. Or... maybe it was just a typo.

It's entirely possible that it was I who misunderstood you. Quantum tunneling is, in a manner of speaking, a way for something to disappear at some place and reappear somewhere else, in a totally continuous way, through its wave function. You wouldn't need any cuts or stitches, or surgical trusses. Then politics came up and I tip-toed away. Wasn't something like that what you meant?

Or quantum tunneling...

Correlation is an effect, or a coincidence. Depends. Most of the times it's an effect of something happening before, or even independently of time. Yeah, sure. It's an effect. An effect of what? Correlation (positive) between A and B. Possibilities: 1) A causes B 2) B causes A 3) Both, A and B, are caused by the same: C 4) A is caused by B plus other factors (not perfect correlation: B makes A more likely) 5) B is caused by A plus other factors (not perfect correlation: A makes B more likely) 6) Both A and B are caused by common cause plus other factors (both are more likely together because antecedent cause C makes both more likely) 7) Coincidence... If you can expand the sample space you can in principle rule this out. I think you're confused beyond recovery here. Also, you constantly cherry-pick what you want to answer. On top of that, you don't distinguish anything relevant here with any care. "Correlation is an effect." Yeah, sure. And a thing is a thing. And what's more, an effect is a something. And something is some thing. Thank you for your illuminating arguments --I'm being sarcastic.

Of what? Of number of people drowning by falling into a pool and Nicholas Cage appearing in a film?

Whois output now gives: Updated Date: 2022-10-20T01:25:16Z Registrar Registration Expiration Date: 2023-10-16T12:23:19Z Previous expiration date was October the 17, if I remember correctly. So brace yourselves in one year's time.

Dear @bangstrom. I think it's very much possible that at the bottom of your misunderstanding of this question is your confusion of causation with correlation. I've just commented on a related topic: The theme "correlation is not causation" could be where you're having difficulties. I do suggest you to do a look-up for that theme on SFN. It's come up before in many different contexts. I've seen statistics in the past going something like "people who take the bus are more prone to getting cancer." A hurried interpretation of this could be true, not because taking the bus is giving you cancer, but because, if you're more likely to take the bus, you're also more likely to be exposed to carcinogens, on the grounds that your lifestyle is more likely to be whithin that particular statistical cohort.ç Anyway, correlation is not causation.

Any conserved quantities are just conserved quantities. After you find out they're conserved, you can look upon these quantities as defined by local densities for them: local density of energy, angular momentum, and so on. But once you mathematically integrate over all values of space, they're just what we call a quantum number. The quantum number is neither here, nor there, but an overall property of the state. Same goes for non-conserved quantities that are nevertheless defined by local densities. Example: expected value of position. Only, we don't call them quantum numbers.

You're confusing correlation with causation. That's not what I'm saying. The experimenter's minds are determined by a common cause, either in the past --exactly as in the singlet state-- or not. Only state of affairs is more complicate in the case of the singlet. Confusing of correlation with causation can be very, very misleading. Sometimes, not even causal connection in the past can be significantly attributed. For causation to be attributed, you must have a theory for the common cause.

That was my best guess after doing a whois search from Linux command line. +1

🤣🤣🤣 Well, they say "often." So often but not here. They want to keep their readers on their toes.

Yes. A classic one: https://en.wikipedia.org/wiki/Lamb_shift Bohr's magneton is the magnetic moment due to orbital motion. That's all it is. The magnetic moment of the electron's spin is expected to be about that when looking at Dirac's equation as if it were a one-particle equation, but it happens to be different. The difference is due to radiative corrections (contributions of virtual particles.) This displaces the values of all physical constants from their quasi-classical value (often called "tree level") to a different value. I'm not sure what you mean, but the g-factor or gyromagnetic ratio (a factor that essentially tells you how much it deviates from a Bohr magneton) of nuclei is all over the place: https://en.wikipedia.org/wiki/Nuclear_magnetic_moment#g-factors Because nuclei are composite objects, I'm sure a lot of the variation has to do with nucleon-nucleon interactions calculable in approximate models, even before you get to radiative corrections. Elementary particles have considerable variance in their magnetic moments too: https://en.wikipedia.org/wiki/Magnetic_moment#Elementary_particles

Photons are not valid frames of reference. You can watch photons do their thing from outside, but you cannot sit on a photon and watch the world from the photon. Einstein considered this just as a gedaken experiment. This is because from the POV of a photon --to the extent that it makes any sense at all-- the world is frozen in one instant of time. Photons are useful thingummyjigs in order to parametrise other things going on, but not useful to parametrise their own view. They have no view. You're getting into the quicksands of quantum gravity here. I'd rather not take that pill just yet.

I'm afraid Mr. Juan Yin --and yourself-- are gonna have to do better than that. If I ask two students, one in Shanghai, and another in Massachusetts --at the same time in a given inertial reference frame-- at which speed the Pythagorean theorem is verified, they will find the speed is infinite. How could that be?: Because the truth of the theorem was already encapsulated in their respective minds long before they performed the measurement. What you say only proves there are people in Shanghai wasting millions of Yuan in measuring very stupid things. It's happened before.

EPR is not an effect, nor is it a "theory" as you say further below this quoted piece of text. EPR is a theoretical argument presented as a contingency: If this (what I propose here) is true, then that (what you've been saying) must be false. If what you've been saying is true (in the face of this example), then something we know for sure (relativistic causality) would have to be false. It's a bit involved, granted. But no "effect" is proposed, and no "theory." And it is a very crude argument in its original form, although it's very astute. The EPR argument, in its original form, is quite flawed. I've tried to explain why somewhere else: https://www.scienceforums.net/topic/127991-an-analogy-for-superposition/#comment-1219399 Nobody said "nothing unusual," and certainly nobody said "nothing non-classical." It's completely non-classical. It's quantum mechanics! ACZ and others performed experiments which bring out the flavour of quantum mechanics at its most strange and counter-intuitive: This fundamental non-reality can be transported at a distance. For one thing, they proved quantum mechanics to be right. For another thing, they managed to keep quantum coherence for very long distances. The last one in particular is a monumental technological achievement. This could be very useful for quantum computing. I'm thinking, eg, that you could delay the decision of defining a qubit until some ancillary calculation is completed. You could decide to set your qubit to a totally random couple of qbit states. It gives you handlers for your qubit logical gates (the AND, the NOT, the OR, the CNOT...). When you transport qubits instead of bits, there's a phenomenally richer set of possibilities. You would have to ask an expert in quantum computing to learn more. But you could do many things with those gates that would be impossible with classical gates.

Exactly. |state of the cat> = (1/sqrt(2))|cat dead>+(1/sqrt(2))|cat alive> These numbers 1/sqrt(2) are called probability amplitudes, and their squares 1/2, 1/2 are the probabilities. I don't want anybody to run away with any hurried conclusions, but the truth is the best analogy for these quantum superpositions is perhaps the human mind itself: When you're not sure about something, it's neither here nor there. It's only when you learn what happened that your mind gets either here or there. In the meantime, there's this Schrödinger equation, which is like the indefinite mind rotating between one and the other. When you measure, the state vector stops on one of the axis. Now, this stopping on one of the axis is called the projection postulate, and is known to be incompatible with the Schrödinger equation.