"But there were experiments with 2 distant entangled particles. If we change the spin of one, another "feels" it IMMEDIATELY ??"
There have been many, many, many experiments with space-like separated entangled "particles". More recently, entanglement has been used as part of an experimental design for an empirical realization of Wheeler's delayed-choice thought experiment. Also, in the "classical" realizations of non-locality/entanglement (i.e., those like Alain Aspect's 1982 breakthrough and Gisin's much more dramatic but still basically the same empirical demonstration of nonlocality), the idea isn't that we "change' one system and therefore affect another. Rather, by knowing the outcome of measurement on one system we are able to determine the state of another, arbitrarily space-like separated system before we've even measured it. More recent experiments with entanglement get wilder (the delayed-choice experiments are pretty interesting), but we still aren't "changing' one system in a way that somehow affects the other. It's more like discovering an existing link of a nature completely alien to us. I've attached one of the better, recent surveys on entanglement that is about as thorough as is possible without being book length (for those, see e.g., Jaeger's very accesible text Entanglement, Information, and the Interpretation of Quantum Mechanics; for an account of entanglement and other aspects of quantum "weirdness" that is also non-technical but not pop. science and is fairly representative of the mainstream views of quantum physics, see SIlverman's Quantum Superposition: Counterintuitive Consequences of Coherence, Entanglement, and Interference)
I don't think there's any perception, aka 'feeling' , nor any propagation. Two elements are entangled if they are representable by two variables bound within a currently valid Schrödinger equation.
As long as decoherence does not intervene, the applicable Schrödinger equation must continue to be valid , and therefore any change affecting one of the variables must be at once reflected by the other variable in a way that the equation continues to be seamlessly coherent and valid. Indeed, there is no expression relating to the spatial separation between variables in Schrödinger's equation: therefore, the inter-variable separation plays no role whatsoever. This is amply demonstrated by experiments (Aspect, Gisin, et al.)
This all seems to indicate that we live in a universe where the fundamental reality is some purely mathematical structure.
When we seek explanations by 'modes of propagation', we are thinking in material terms - a cognitive bias born of our evolution in a physical, palpable world - but we are most likely barking up the wrong tree.
Thanks ones again, Dr. Ransford. An interesting viewpoint about a "purely mathematical structure". But there were experiments with 2 distant entangled particles. If we change the spin of one, another "feels" it IMMEDIATELY ??
Of course - there is a vast body of such experiments, Alain Aspect, Nicolas Gisin, et al. Again, it's because separation does not figure at all in Schrödinger's equation, hence the adaptation of an entangled object to any change affecting its mate(s) is immediate, so that a valid Schrödinger equation not be violated.
"But there were experiments with 2 distant entangled particles. If we change the spin of one, another "feels" it IMMEDIATELY ??"
There have been many, many, many experiments with space-like separated entangled "particles". More recently, entanglement has been used as part of an experimental design for an empirical realization of Wheeler's delayed-choice thought experiment. Also, in the "classical" realizations of non-locality/entanglement (i.e., those like Alain Aspect's 1982 breakthrough and Gisin's much more dramatic but still basically the same empirical demonstration of nonlocality), the idea isn't that we "change' one system and therefore affect another. Rather, by knowing the outcome of measurement on one system we are able to determine the state of another, arbitrarily space-like separated system before we've even measured it. More recent experiments with entanglement get wilder (the delayed-choice experiments are pretty interesting), but we still aren't "changing' one system in a way that somehow affects the other. It's more like discovering an existing link of a nature completely alien to us. I've attached one of the better, recent surveys on entanglement that is about as thorough as is possible without being book length (for those, see e.g., Jaeger's very accesible text Entanglement, Information, and the Interpretation of Quantum Mechanics; for an account of entanglement and other aspects of quantum "weirdness" that is also non-technical but not pop. science and is fairly representative of the mainstream views of quantum physics, see SIlverman's Quantum Superposition: Counterintuitive Consequences of Coherence, Entanglement, and Interference)
Sofia, maybe you misread the texts.
The mathematics demonstrates that an entangled particle must react at once to any change that would otherwise lead to a violation of Schrödinger's equation. There is no question of 'immediately felt' anywhere - there is an adaptation of physical circumstances such that valid mathematical equations shall not be violated.
The very same holds in the case of, say, e=mc² , a purely mathematical equation easily derived from simple mathematics, which however leads to the actuality of nuclear reactions. If nuclear reactions did not exist, then the equation e=mc² would be violated - a circumstance that our universe has never been caught allowing.
In the narrow case of Bell's equations, or of, say, delayed choice experiments, and many such others, you could argue that there is an alternative that either the physics (the spooky actions at a distance, say), or the math, shall be falsified. In every single such case, the mathematics has always been correct (and hence you could argue that the 'physics' has been falsified.) This leads to a view that this is a mathematical universe.
Dear H Chris Ransford:
"The mathematics demonstrates than an entangled particle must...."
Mathematics cannot demonstrate what anything "must" do outside the closed discourse realm/formal system in which mathematical expressions, derivations, etc. exist. For example:
"The very same holds in the case of, say, e=mc² , a purely mathematical equation easily derived from simple mathematics"
This is neither a purely mathematical equation (one need only see how many times "e" is used in mathematics to denote Euler's number rather than energy), nor is it "easily derived from simple mathematics." One cannot derive the speed of light mathematically, only empirically. It is derived from changes made to pre-relativistic equations which were based upon a theoretical framework itself a combination of mathematics and empirical study, and simplification to give us an expression of rest mass (that, incidentally, is completely wrong if we are considering massless particles, demonstrating in a different way that it is not a "purely mathematical" anything).
"In every single such case, the mathematics has always been correct"
1) Were this true, then we wouldn't have classical physics, because there would be no modern physics: all the equations from classical physics would be correct. The mathematics have usually been wrong.
2) Currently, the mathematics governing mechanics in general relativity is incompatible with the whole of quantum physics.
3) Bell's equations, which are about as close as we can get to mathematics that depend only upon mathematical axioms (i.e., depend only upon the system/formal languge in question), is questioned despite the minimal assumptions built into his theorem.
4) "Spooky action at a distance" was derived from the formalism of quantum mechanics. EPR makes this quite clear. A central problem in modern physics is mathematics. Because so much of modern physics is based upon e.g., changing the mathematics of QM in order to incorporate e.g., electrodynamics and relativity, and because QM is fundamentally, irreducibly statistical in nature, it is unclear how the mathematics corresponds to reality in many cases and worse still what the mathematics allows vs. what reality would seem to. An easy example would be the admission of CTCs in general relativity. The math allows one to interact with one's self in the past (it's far more general, actually, which makes it far worse).
5) The mathematics is physics here. That's how we know that in the equation e=mc2 the "e" isn't Euler's constant. Mathematics can't win. I can mathematically define just about anything I wish so long as I adhere to the structure I create. In physics, the farther away from the physics we get, the worse the results we can get from mathematics can become (and the more diverse).
I fully subscribe to what Andrew says that by measuring one particle, "we still aren't "changing' one system in a way that somehow affects the other". Regretfully, I disagree with the idea that "we live in a universe where the fundamental reality is some purely mathematical structure". The nature works by physical processes, and we invent and adjust different mathematical formalisms for describing as close as possible those processes. The idea to just work with the mathematics without trying to understand the natural process, is anti-research.
I the case of entanglements the nature manages the entangled particles in a smart way that at present we understand only partially. What is known is that nothing is transmitted between the distant particles. Each particle gives its response at a measurement by picking probabilistically an answer according to its reduced density matrix. However, the nature has a way to block forbidden combinations of answers.
The idea that what happens with one of the particle is immediately felt by another particle is non-physical. We live in a universe in which the time is not absolute, and simultaneity of events is relative. According to a moving frame of coordinates the measurements of the two particles are simultaneous, by another frame Alice measures first, and by still another frame Bob measures first. Thus, we cannot say that the result obtained by Bob is immediately felt during Alice's measurement, as there exists a frame in which Alice measures first. From analogous considerations the vice-versa is also true, we cannot say that during Bob's measurement the result obtained by Alice is felt.
It remains for us to find in which way the nature proceeds for blocking the forbidden combinations. About this, different interpretations of the QM hint of different ways.
Andrew, a proper answer to your post would be quite long, I'll try to tackle that when I have more available time .
A brief first note though - there is the old semantic issue of what is understood by mathematics. By 'mathematics' is understood here pure mathematics, in the Monastyrsky sense, not applied math nor mathematical modelling.
Dear Natalia ,
The second particle does not "feel". Because of entangled particles don't exist! Indeed, the two particles can get into exactly the same conditions at the very same moment, and receive the same state. Thus, all particles must get all their properties at their birth.
And the Nature no need to block prohibited combinations of states, because such combinations not exist.
Experiments with 2 distant entangled particles incorrectly interpreted and are useless.
Unfortunately, modern Particle Physics came to a standstill when completely unreasonable an incorrect formulation of the uncertainty principle was introduced in her.
It is my point of view.
---
Уважаемая Natalia ,
Никак она не чувствует. Поскольку спутанных частиц не существует! Действительно, ведь обе частицы могут попасть в совершенно одинаковые условия совершенно одновременно, и получить одинаковые состояния. Таким образом, все частицы получают все свои свойства при своем рождении.
И Природе нет необходимости блокировать запрещенные комбинации ответов, потому что таких комбинаций нет.
Эксперименты с 2 далекими запутанными частицами неправильно трактуются и являются бесполезными.
К сожалению, современная Particle Physics попала в тупик, когда полностью необоснованно в нее ввели неверную формулировку принципа неопределенности.
Это моя точка зрения.
Dear Alexander , thank you very much for sharing your interesting viewpoint !
Dear Natalia, thank you for understanding me. Task for particle physicists is to find other way to describing of effects which led to incorrect formulation of the uncertainty principle.
--
Уважаемая Наталья, благодарю вас за понимание меня. Задача для физиков-элементарщиков - найти другой способ описания эффектов, которые привели к некорректной формулировке принципа неопределенности.
Due to the joint amplitudes.
In an entanglement of two particles A and B,
(1) α|x>A|x>B> + β|y>A|y>B,
if one tests the particle A and gets x, no wave-packet |y> impinges the detectors of particle B, because the joint amplitude of |x>A|y>B> is NULL.
A good question in continuation is what happens in this case with the coupling |y>A|y>B, but this is another question than asked in this thread.
entanglement has nothing to do with Dirac material. Photons, for instance, are bosons. Neither has the tunneling anything to do with entanglement. As to disentangling, no unitary operations changes an entanglement. Entangle and disentngle -- wht's this? Physics is no abracadabra.
Dear Sofia,
In my opinion, the two entangled particles decided to took those related physical values in coordination while being adjacent! and we observed this physical values right after their quantum jumps, and no any correlation exists after the moment of jumps achievement wich is the moment of wave collapse.
The jump velocity may exceed the speed of light but the mean velocity still less than of light.
And sure these physical values are related to the stuff of experiment, and it confirms the nonlocality behavior in quantum mechanic like the issue related to Bell's inequality.
With best regards.
Dear Bernd,
of course I can use a moderate sound.
The issue is that you introduce in the discussion issues that have nothing to do with the entanglement. Well, you just come from other domains, not from the domain of "foundations of QM" to which this question belongs. That's nothing wrong with this, to the contrary! QM fascinates extremely many people, belonging or not to the domain.
I do belong to this domain, I study it for tens of years. I daresay that I understand a good couple of things in it - of course not absolutely everything. Also, we need more experiments.
Fortunately, how entanglements work, is no more a secret. The fact that in an entanglement some combinations of results were suppressed from the stage of preparation, implies that some combinations (the same or others) are suppressed in the final wave-function. Such combinations of results have amplitude of probability zero, e.f. if the result x appears for particle A, the wave-packet |y>B is destroyed by multi-particle interference. Thus, there is no possibility for the result x of A and y of B. SIMPLY and CLEAN!
This is why I invite you to read that answer of mine in which appears the line
(1) α|x>A|x>B> + β|y>A|y>B.
Tunneling is not a phenomenon of entanglement - entanglement is between two or more particles as shows the formula above. As you disentanglement, what you mean by that? An entanglement does not undergo disentenglement without a non-unitary intervention.
So, NO! The Nature is subtle, the micro-world is governed by laws that we have to try very hardly for understanding, but there is no abracadabra. There are rigorous laws.
Lovely Mazen,
"In my opinion, the two entangled particles decided to took those related physical values in coordination while being adjacent!"
I am not sure what you mean by "coordination". I believe that you mean that which combinations of results appear in the wave-function, and which do not appear, is prepared at the time of preparation of the wave-function. This is perfectly true.
But I don't understand of which "jumps " you speak.
With kind regards from me!
Dear Bernd,
A person who understands a certain issue is able to explain the issue by himself/herself.
I explain what I mean, by myself. About your references, I don't have time to read them - if you can't explain the concepts you use, by yourself, I am sorry but I don't have to pay with my time.
"Where foundations of mathematical physics is concerned, I am familiar with your formulas and with the phenomenology of entangled states (as much as seems to be known today)."
What is known today to whom?
Bernd,
I KNOW HOW THE ENTANGLEMENTS WORK. Therefore, no need to waste time on me. I am not with this problem anymore. Moreover, I understand - PARTIALLY - WHY the so-called "collapse of the wave-function" occurs. Neither this is anymore a problem for me.
Bernd, the Nature is of an extraordinary subtility and smartness. Sometimes, we try to understand Her by formulating complicated hypotheses and equations. And She laughs at us because Her geniality is in simplicity - smart tricks. I said that physics is not abracadabra because EVERYTHING HAS AN EXPLANATION, there are no miracles. For instance, the nonlocality of the entanglements is a smart trick, completely understood today.
The issue that preoccupies me now is whether Peres was right in saying "there is no collapse – there are no miracles“. What he spoke about was the belief, not justified by any experiment (but also not contradicted), that at the macroscopic measurement of a quantum object, part of the wave-function disappears. It seems indeed irreasonable: in our apparatus travels something, how can part of that "thing" disappear? There is no abracadabra. Many contradictions stem from this hypothesis of disappearence. So, probably, this is not the way the Nature works.
About your feeling that the quantum object is not a particle, I subscribe. But since this object has a distributed behavior - e.g. collects phase-shifts from different parts of the space (Tan, Walls, Colett experiment) - it is a wave. No doubt, it's a wave with strage properties. For understand how they work, we have to try to understand which tricks the Nature uses.
Best regards,
Sofia
To Bernd, Natalia, and all the other users!
The way the entanglements achieve their nonlocality is very simple. It's a trick of the Nature.
Let's take for instance the well-known polarization singlet,
|x>A |x>B + |y>A |y>B.
It's trivial to check that if Alice measures her photon's polarization in the base { |x'>, |y'> }, and gets the answer x', NO WAVE-PACKET |y'> enters Bob's detectors. That happens because the combination |x'>A |y'>B is erased by the TWO-PARTICLE INTERFERENCE. If one does the calculus one gets that all the contributions to the combination |x'>A |y'>B cancel out among themselves.
The two-particle amplitudes erase or enhance combinations of results, as if the two particles were one near the other.
This is the trick the Nature uses: TWO-PARTICLE COMPLEX AMPLITUDES. In the macroscopic world we don't have multi-particle amplitudes, and not even single-particle amplitudes. The dimensions of the objects are two much big in comparison with the wavelength of their movement. Thus, if we would try to write a wave-function for such objects, we could not say what are the phases of the amplitudes. For instance, if we try to define the center of a macroscopic object, the imprecision is extremely many times greater than the wavelength of the movement.
Oh, Bernd,
I don't laugh at anybody.
Now, I placed an explanation on how the entanglements work, because this is the question Natalia asked. It's just above your post. It's a rigorous explanation. But you ignored it completely.
It can't go like that. To have a coherent talk - not each one of us speaking of something else - I ask you to tell me if you understood my explanation, or, if you see an error. You say that you know well the quantum formalism, so you can't have a problem with my proof which is absolutely elementary.
We can discuss other things too, but, if you ignore my post it's a talk between deaf people.
With kind regards,
Sofia
For me entanglement is only relevant if you have interation at some point in time at least.
Say between two spin 1/2 particles, forming a spin 0, near t=0, presumably then interact a one entity.
Then as they fly apart, interaction goes to zero, but the spin correlation remains intact, but just because
the states evolve continuously, in a smooth way.
Otherwise you can put a psi) xi) on anything with anything, which would not make sense.
When the two particles are identical you should also contemplate Fermi statistics. so that the whole is
antisymmetric under interchange.
This implies that two entangled things has to be treated holistically as one at all time, cannot talk about what changes one makes and not in the other.
Bernd,
there is a saying that if one runs after two rabbits at once, one catches none. I showed you how the entanglements work. Entanglements means just that some combinations of results cannot appear, and I showed you where from comes this effect. It is this effect that makes people ask "how does Bob's particle KNOW what responded Alice's particle?" And I showed you that Bob's particle KNOWS NOTHING about Alice's particle, that the effect looking as nonlocality is a consequence of superposition, constructive or destructive of the joint amplitudes. If you look at the terms in an entanglement, each term is a product of states of the two particles, preceded by an amplitude common to the two particles.
Now, you say that it is correct and you don't understand it. I don't know such a type of logic. It is as saying that I am white but I am black. PLESE DECIDE!
Also, I don't know what means to write in front and background for being dissatisfied. Please do not talk to me in riddles.
About the coherence of your talk, I am not there yet. It may be coherent but it is not coherent with what I told you. When I expose a rationale, I expect first to conclude with you that rationale. Only AFTER THAT we may run after another rabbit - i.e. talk on other things.
As you are a busy person, and aged, so am I. To remind you, this thread is about E N T A N G L E M E N T S. And I explained how they work. If you did not understand my proof, I invite you to place the finger on the point where I lost you. On the other hand, if you are not interested on how they work please let me know, s.t. I would economize my time.
Anyway, I do not run after two rabbits at once, I am too much busy, I need order in discussion.
With kind regards
Juan, did you read my proof on how entanglements work? I wrote it in this thread one day ago. It begins with "To Bernd, Natalia, and all the other users!".
However, one step at one time. I explained you why the concept of particle does not make sense, at
https://www.researchgate.net/post/Could_this_be_a_NO-GO_of_the_quantum_mechanics
Let's not make a salad of things, let's clarify one thing at one time. So, please, pay attention at my explanation about the contradiction to which leads the concept of particle.
Now it's very late in my country, "tomorrow is another day". Pleasant dreams!
Well if you have two entangled particles, and you use a two particle wave function, all is fine. If identical
they are radically indistinguishable, a quantum phenomena where it even makes no sense to talk about
particle a and particle b. So you cannot mix with an essentially clasic SR conception where the distinction is important.
In your arguments you do have particle a and particle b.
This however should not imply that I cannot talk about particle at all. Got it?
regards, juan
Juan,
Look at my answers in my questions with NO-GO. As I said, I can't run after two rabbits at once. Let's clarify one thing, and after that the other.
Well, I have to go to sleep immediately.
Mr. Schmeikal should know that he has no right to make public things that another person tells him privately. Moreover, it's ResearchGate here, it's exchange of scientific arguments, not column of gossip. I feel disgust and I salute his decision to withdraw from talking with me. I only hope to God that he'll keep his decision.
A radio station is entangled with a radio. Likewise entangled particles may be causing waves in an ether (as Bohmian mechanics can allow) with like or once connected particles share similar wave characteristics which resonate.
Sofia
You ask if there is quantum SR.
Well, at least approximately, with the Dirac equation in the quantum, shown also to be Lorenz invariant.
However you are still bound by specific quantum rules, that make the quantum quite different.
regards, juan
Juan,
The relativistic QM obeying the Dirac equation does not mean that there exists a quantum relativity. Dirac's equation obeys the same Lorentz transformations. It's QM adapted to relativity, not vice-versa.
A quantized relativity would mean some quantization of the space-time, or God knows which thing, but dirac equation has nothing to do with that.
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