| 1 Nicolaas Vroom | Nobel price physics 2022 | Monday 10 October 2022 |
| 2 Austin Fearnley | Re :Nobel price physics 2022 | Thursday 13 October 2022 |
| 3 richali...@gmail.com | Re :Nobel price physics 2022 | Sunday 16 October 2022 |
| 4 ju...@diegidio.nam | Re :Nobel price physics 2022 | Monday 17 October 2022 |
| 5 Tom Roberts | Re :Nobel price physics 2022 | Monday 17 October 2022 |
| 6 richali...@gmail.com | Re :Nobel price physics 2022 | Monday 17 October 2022 |
| 7 Austin Fearnley | Re :Nobel price physics 2022 | Tuesday 18 October 2022 |
| 8 Stefan Ram | Re :Nobel price physics 2022 | Tuesday 18 October 2022 |
| 9 Nicolaas Vroom | Re :Nobel price physics 2022 | Friday 21 October 2022 |
| 10 Sylvia Else | Re :Nobel price physics 2022 | Monday 24 October 2022 |
| 11 Nicolaas Vroom | Re :Nobel price physics 2022 | Tuesday 25 October 2022 |
Nobel price physics 2022
0 posts by 1 author
https://groups.google.com/g/sci.physics.research/c/rf6a1AyvS0s
keywords = entanglement
64 weergaven
For background information about this price read this document:
(1) https://www.nobelprize.org/uploads/2022/10/advanced-physicsprize2022.pdf
One of the best documents, mentioned in this document, is the document
(2) https://escholarship.org/uc/item/1kb7660q by Carl Alvin Kocher in 1967.
This brilliant Ph. D. Thesis clearly explains the reaction involved how to
produce entangled photons. What this document indirect shows, is that to
demonstrate polarization correlation, no thought experiment can be used.
This document states: "A measurement made on one particle can affect the
result of a subsequent measurement on another particle of the same system,
even though the particles may be non-interacting and separated in space."
The question is if that is correct.
The point is, first you have to establish this correlation by performing
1000 experiments on both particles. The result will be that this reaction
produces 'always' 2 correlated photons. That does not mean that the
measurement of one affects the other. It is the specific reaction which
causes this correlation.
In document (1) at page 5 is written: "Schroedinger's cat is bizarre".
My first remark is that you can't do this experiment as a thought experiment,
but besides that you should try to perform this experiment as simple as
possible. This is a description:
Take a wooden box and place a cat, alive, in that box. Close the box.
After 5 minutes you open the box, and observe the state of the cat.
But before you open the box, the experimenter declares that the cat
is both alive and dead. It is not clear what he means. Because the state
of the cat is determined by the physical condition of the cat and how long
the cat is in the box. But not by any human involvement.
You can repeat this experiment 1000 times and observe the state of the cat
after 5 minutes, (or any duration) but always is the cat either alive or dead.
You can also replace the wooden box by box made from glass, but that makes
no difference for the final outcome. The only difference is when the cat
dies, you can establish the moment when this happens.
You can also make what happens inside the box more complex, but that does
not make any difference; you can't claim that the cat is in two states
simultaneous.
It also does not make sense to claim, that Schroedinger's cat would be
alive in one world and dead in another. See page 3. Such a statement can't
be tested by means of any experiment.
Nicolaas Vroom https://www.nicvroom.be/
I am an amateur physicist, just at the point of calling it a day. I have a few days ago put online my final physics paper: on preons and Bell's experiment. So I hope you allow this post as a swan song.
Of course the experimentalists have worked well for their prizes. But the theoreticians still have work to do on this topic.
In the late 1960s I read a book about quantum particles on the magical world of Mr Tomkins. It was very exciting at the time but I now believe it is very wrong physics. Particle entanglement of states is merely a sign that calculations and observations cannot separate two items of raw data, instead only the average is available. The raw data are not available for entanglement, only the statistical, average value data are available. Forget dead/alive cats as that is a distraction (and a waste of time). Consider particles entangled with one another and with unknown spin states. The most believable assumption in my opinion is that nothing travels faster than light. Associated with this assumption is that retrocausality is the key to this problem.
The implication of retrocausality is that quantum computers have no foundation in physics as particle always have local hidden variables. Also that time is two-way at the microscopic level. It is possible that quantum cryptography is supported by retrocausality as there is an apparent action at a distance despite nothing physically travelling faster than light locally.
Austin Fearnley
| > |
...
...The most believable assumption in my opinion is that nothing
travels faster than light. Associated with this assumption is that
retrocausality is the key to this problem.
The implication of retrocausality is that quantum computers have no foundation in physics as particle always have local hidden variables. Also that time is two-way at the microscopic level. It is possible that quantum cryptography is supported by retrocausality as there is an apparent action at a distance despite nothing physically travelling faster than light locally. Austin Fearnley |
Austin,
I think I am in general agreement with you. If you assume no communication of any kind faster than the speed of light then "retrocausality" or "superdeterminism" are the natural conclusions. If, on the other hand you accept faster than light coordination between two distant detection events you necessarily have an ambiguous causality sequence, which I don't like.
It appears to me that while there are a significant number of physicists that accept, or are willing to consider, retrocausality, it is still not a mainstream concept among physicists. I think the hesitation is related to the idea of free will and the ability to determine your own future. Unfortunately this is probably on the boarder of proper science since it may be untestable and unfalsifiable. I would be very interested in an idea for testing these ideas experimentally in a more transparent way than the entanglement experiments.
Rich L.
| > | But before you open the box, the experimenter declares that the cat is both alive and dead. It is not clear what he means. |
That is not what "the experimenter declares", that is rather the gist of Schroedinger's paradox, that *the theory* says the cat *is in a superposition of states*, and what the "paradoxical" consequences of taking the theory at face value, i.e. for serious, may be.
So, it is not clear what *the theory* means: which, as I have been explaining in another recent thread, overall is a question and an issue of ontology...
Julio
| > | On Thursday, October 13, 2022 at 2:59:07 PM UTC-5, Austin Fearnley wrote: |
| >> | [...] |
You are both overthinking this.
Consider a generic experiment on quantum entanglement: Two particles are created at event A in an entangled state, they are separated and transported to events B and C, where their individual properties are measured; B and C are spacelike-separated events.
It is observed that: a) one cannot predict the outcome of either measurement b) when the results of the two measurements are brought together and compared, they are found to have the same correlation as when the particles remain at A and are measured there simultaneously.
Why would anyone think "retrocausality" is involved here? The path of causality is quite clear: from A to B and independently from A to C -- there is no causal link between B and C. The fact that the particles at B and C have a property that is correlated is curious, and violates classical notions of locality, but is not any sort of refutation of causality.
The source of this confusion is clear: thinking these are "individual properties", when in fact such ENTANGLED properties are not individual to the two particles.
Tom Roberts
| > | On 10/16/22 7:09 AM, Richard Livingston wrote: |
| > > | On Thursday, October 13, 2022 at 2:59:07 PM UTC-5, Austin Fearnley wrote: |
| > >> | [...] |
| > |
You are both overthinking this. ... The source of this confusion is clear: thinking these are "individual properties", when in fact such ENTANGLED properties are not individual to the two particles. Tom Roberts |
I disagree, I believe there is something to understand about how these correlations are maintained over such space-time separations.
I believe the point of view of QM is that the two "entangled" particles are in effect a single thing. Certainly the math treats it that way. Suskind et al. have speculated that the two particles are connected by a wormhole, and thus they are able to coordinate their behaviors over spatially separated space-time distances. I'm skeptical of this idea for several reasons: 1) wormholes have never been observed, 2) wormholes are a speculated GR effect and it isn't clear to me that photons can have the energy density to warp space-time as required, and 3) it treats photons as localized particles, which I think is a big misconception.
But I don't know, nobody does yet.
The reason I think there is something to understand here is that the coordination of results is clearly not a local effect. The state of the detectors have been changed randomly and rapidly in some experiments and still the required correlations observed. Some how the correlations were preserved even when the detection conditions changed after emission. This requires either that the detection events coordinated their response (at faster than the speed of light) or that the detection events somehow affected the properties of the emitted photons (i.e. retro-causality).
These ideas are controversial because they are so counter to our everyday experience. Just saying that the correlations happen is ignoring the question of how they happen. While it appears that many physicists choose to not question the mysteries of QM, I think that is ignoring the possibility of discovering new physics. It might be like saying Newtonian gravity is the final law and ignoring the small unexplained precision of Mercury. We should ALWAYS wonder if there is another layer to be discovered.
Rich L.
I have no ideas about how to introduce free will into a framework of deterministic calculations that the universe appears to need. Chaos can be introduced into calculations using non linear equations but chaos is not free will? One would need guided-by-free-will use of non-linear equations. Anyway, I am hanging up my Physics hat and at 73 years of age feel that I am now too old to work hard enough on physics.
You mention testing. I have obviously thought, but without success, about how to test whether antiparticles are travelling backwards in time. For an antiparticle, under my assumption, the polarisation vector changes from a random vector to vector d or -d (= detector setting vector) at measurement, in the antiparticle's own, reversed time direction. This appears to be a change from vector d or -d to a random polarisation in the forward time direction. Adding extra test measurements before or after the main measurement would always seem to me to interfere too much and ruin the test.
I am glad you responded to Tom as I could not have responded so well.
Tom: "The fact that the particles at B and C have a property that is correlated is curious"
Alice: curiouser and curiouser Bob: seems darned well spooky to me
My own speculation about Susskind's wormhole connection is that particles are in dS while antiparticles are in AdS. This is complicated in my preon model where each and every particle has both forwards and backwards-in-time preons within it. Entanglement (of particle and antiparticle) is probably involved in construction of spacetime metrics as the metric forms in the zone where both dS and AdS meet which has minimal curvature. But that speculation is probably rubbish. Although most particles are matter, they overall have an equal number of (my) preons and antipreons within them. So the loss of antimatter is caused by spontaneous symmetry breaking in forming elementary particles from preons.
| > | I have no ideas about how to introduce free will into a |
What do you mean by "free will"?
| > | Consider a generic experiment on quantum entanglement: Two particles are created at event A in an entangled state, they are separated and transported to events B and C, where their individual properties are measured; B and C are spacelike-separated events. |
What I understand is that you perform an experiment which involves entangeled particles in two ways: (See https://escholarship.org/uc/item/1kb7660q by Carl Alvin Kocher in 1967. This thesis explains the reaction involved how to produce entangled photons.) First local. The two particles are created as event A and local measured as event A1 and A2. Both particles are correlated in the sense when event A1 indicates up, event A2 indicates down. Secondly more global. The two particles are created as event A and measured at a certain distance as event B and C. Both particles are correlated in the sense when event B indicates up, event C indicates down.
| > | It is observed that: b) when the results of the two measurements are brought together and compared, they are found to have the same correlation as when the particles remain at A and are measured there simultaneously. |
| > | Why would anyone think "retrocausality" is involved here? The path of causality is quite clear: from A to B and independently from A to C -- there is no causal link between B and C. |
| > | The fact that the particles at B and C have a property that is correlated is curious, and violates classical notions of locality, but is not any sort of refutation of causality. |
| > | The source of this confusion is clear: thinking these are "individual properties", when in fact such ENTANGLED properties are not individual to the two particles. |
Nicolaas Vroom
However, once measurements are made on axes at other angles to each other, the correlations are no longer explainable that way, and locality is brought into question.
Sylvia.
| > | I disagree, I believe there is something to understand about how these correlations are maintained over such space-time separations. |
| > | I believe the point of view of QM is that the two "entangled" particles are in effect a single thing. |
| > | Certainly, the math treats it that way. |
| > | Suskind et al. have speculated that the two particles are connected by a wormhole, and thus they are able to coordinate their behaviours over spatially separated space-time distances. |
| > | I'm sceptical of this idea for several reasons: |
| > | The reason I think there is something to understand here is that the coordination of results is clearly not a local effect. |
| > | These ideas are controversial because they are so counter to our everyday experience. Just saying that the correlations happen is ignoring the question of how they happen. |
In case 3 the measurement equipment is more complex to establish the correlation between the photons. That means you both have to measure the fact that there are photons involved and the direction of the spin in either the x, y or z direction. Also, in this case there is no reason to assume that the measurement of the spin-direction of one photon influences the spin-direction of the other photon.
Suppose, (1) based on multiple experiments, that the direction of the two photons created is always in one line, but in opposite directions. Do you think, that (2) when a mirror is placed in one path and the photon will be reflected, that (3) the direction, of an other photon (without a mirror) also will be 'reflected'. IMO the answer is No.
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