[HN Gopher] Nobel Prize in Physics Awarded to Alain Aspect, John...
___________________________________________________________________
Nobel Prize in Physics Awarded to Alain Aspect, John Clauser and
Anton Zeilinger
Author : solarist
Score : 255 points
Date : 2022-10-04 09:50 UTC (13 hours ago)
(HTM) web link (www.nobelprize.org)
(TXT) w3m dump (www.nobelprize.org)
| lokimedes wrote:
| That is a strongly deserving selection.
| [deleted]
| leoc wrote:
| Some fun background on the history and politics involved:
| https://arxiv.org/ftp/physics/papers/0508/0508180.pdf . Clauser
| is apparently the guy who took most of the arrows in the back for
| advocating experimental tests of quantum mechanics. It seems that
| he and Feynman weren't big mutual admirers:
| https://www.aip.org/history-programs/niels-bohr-library/oral... .
| UniverseHacker wrote:
| John Clauser is a raging asshole, and isn't much an admirer of
| anybody, let alone "a ******* moron like Feynman." I say this
| as a friend of his, and I'm nearly certain those are the exact
| words he'd choose to describe both himself, and Feynman.
| Interestingly, I feel there's a certain good natured
| lightheartedness to Clauser's 'arrogant asshole genius'
| persona, as if he is consciously acting that way as a comedic
| performance. This Nobel Prize will feed perfectly into this,
| he's going to love it.
|
| Edit: I'm normally not one to complain about well deserved
| downvotes, but I think people may be missing my joking tone,
| and context here. Once a few people that also know Clauser give
| thoughtful replies in this discussion, it will make more sense.
| [deleted]
| keepquestioning wrote:
| Have I seen any of the fruits of this labour in my daily life, or
| is this for stuff like string theory?
| kergonath wrote:
| Their work is based on experimental verification of some very
| counter-intuitive aspects (!) of quantum theory. Just this put
| them in a completely different world than string theorists, who
| still don't know how to test their theory.
|
| As mentioned elsewhere, their work is the foundation of quantum
| computing and quantum cryptography, which probably hasn't
| directly affected your life yet but could very well do so in a
| not-too-far future. Again, entirely unlike string theory.
| keepquestioning wrote:
| Isn't Quantum Computing bullshit?
| [deleted]
| Nokinside wrote:
| Huh. I thought Zeilinger already had Nobel.
|
| He certainly deserves it. He is incredible experimentalist:
|
| - Macroscopic quantum inference with molecules like C70.
|
| - two photon orbital angular momentum entanglement with 600
| difference in quantum number.
|
| - multi-particle entangement.
|
| - quantum teleportation
| Nokinside wrote:
| .. and his work of testing of quantum mechanics goes on from
| far to weird:
|
| Cosmic Bell Test using Random Measurement Settings from High-
| Redshift Quasars (2018)
| https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.12...
| > .. This experiment pushes back to at least ~7.8 Gyr ago the
| most recent time by which any local-realist influences could
| have exploited the "freedom-of-choice" loophole to engineer the
| observed Bell violation, excluding any such mechanism from 96%
| of the space-time volume of the past light cone of our
| experiment, extending from the big bang to today.
|
| Challenging local realism with human choices
| https://www.nature.com/articles/s41586-018-0085-3
|
| >Bell himself noted this weakness in using physical setting
| choices and argued that human 'free will' could be used
| rigorously to ensure unpredictability in Bell tests8. Here we
| report a set of local-realism tests using human choices, which
| avoids assumptions about predictability in physics. We
| recruited about 100,000 human participants to play an online
| video game that incentivizes fast, sustained input of
| unpredictable selections and illustrates Bell-test methodology
|
| >... Project outcomes include closing the 'freedom-of-choice
| loophole' (the possibility that the setting choices are
| influenced by 'hidden variables' to correlate with the particle
| properties
| bumby wrote:
| > _Bell himself noted this weakness in using physical setting
| choices and argued that human 'free will' could be used
| rigorously to ensure unpredictability in Bell tests_
|
| Please don't flame me if this is an outrageous question,
| because I readily admit I know nothing on the topic of
| quantum physics, but isn't it a quite large limitation to
| assume human free will as a given? Or is "free-will" meant as
| a proxy for "pseudo-random" and that's enough for this
| experiment?
| mdorazio wrote:
| See here: https://www.pnas.org/doi/10.1073/pnas.1002780107
|
| It has to do with true randomness in the measurement
| aspect, not with human free will.
| kgwgk wrote:
| How is "free will" different from the "freedom of choice"
| extensively discussed in that link - "as crucial as
| realism and locality in the derivation of Bell's
| theorem"?
| Arrath wrote:
| Well I have some reading to do because that meant very little
| to me yet I am very intrigued.
| ortusdux wrote:
| There is a great NOVA documentary about the High-Redshift
| Quasars experiment - Einstein's Quantum Riddle (2019).
|
| https://www.youtube.com/watch?v=Mn4AwineA5o
| seydor wrote:
| I thought all three of them had!
| luc4sdreyer wrote:
| Zeilinger got the Wolf Prize in Physics in 2010, which is often
| considered the second most prestigious award after the Nobel
| prize.
| kgwgk wrote:
| The three of them did. (I was unaware about that prize until
| now - or maybe I had forgotten.)
| sigmoid10 wrote:
| They probably also got scared that he would die before he could
| ever get it. Same as with Penrose two years ago, if Zeilinger
| had gone without a Nobel, that would almost be a disgrace for
| the price.
| sidcool wrote:
| ELI5 anyone on their achievements?
| solarist wrote:
| The press-release has a fair summary:
| https://www.nobelprize.org/prizes/physics/2022/press-release...
|
| Also here for a bit of history:
| https://en.wikipedia.org/wiki/Bell_test
| shmageggy wrote:
| Note there are two pdfs with more detail linked at the bottom
| under "Read more about this year's prize"
|
| Popular science background: How entanglement has become a
| powerful tool (pdf)
|
| Scientific Background: "For experiments with entangled
| photons, establishing the violation of Bell inequalities and
| pioneering quantum information science" (pdf)
| hackandthink wrote:
| Popular Science Background: "Quantum mechanics' most
| important resource" (Entangled quantum states)
|
| From a Quantum Computing perspective entanglement ist kind
| of overrated.
|
| Scott Aaronson: How Much Structure Is Needed for Huge
| Quantum Speedups?
|
| https://arxiv.org/pdf/2209.06930.pdf
|
| Actually entanglement is not mentioned at all.
| krastanov wrote:
| Except for error correction, sensing beyond the classical
| limit, teleportation, key distribution, most forms of
| fault tolerance, cluster state computation, blind
| computation, one way computation, and more.
| hackandthink wrote:
| Sure you are right.
|
| This is just a computational Perspective.
|
| Gottesman-Knill Theorem:
|
| "The theorem proves that, for all quantum algorithms with
| a speed up that relies on entanglement which can be
| achieved with a CNOT and a Hadamard gate to produce
| entangled states, this kind of entanglement alone does
| not give any computing advantage."
|
| Entanglement alone is not sufficient for algorithmic
| speedup.
|
| Again Wikipedia:
|
| "The reason for the speed up of quantum computers is not
| yet fully understood"
| hackandthink wrote:
| Intuitively or naively there's some connection:
|
| (1) the dimension of the Tensorproduct Space of n
| entangled Qubits is 2^n.
|
| (2) exponential speedup
|
| but which?
| pkrumins wrote:
| The best way to understand what they did is to watch the so
| called award lecture. Each laureate gives an hour long lecture
| which is video taped where they explain what they did. Google for
| Nobel Prize Award Lecture.
| solarist wrote:
| Even in THE press conference of the Nobel Physics prize, one
| cannot expect to get the facts fully communicated clearly.
| Superdeterminism is a local hidden-variable theory that
| reproduces the predictions of quantum mechanics.
|
| Edit: Sabine Hossenfelder has explained this much better than I
| ever can: See for example
| http://backreaction.blogspot.com/2021/12/does-superdetermini...
| shusaku wrote:
| I think people are downvoting you because they missed the
| mistake in the press release, so it sounds like you were
| claiming super determinism is the definitive theory
| Strilanc wrote:
| Have people actually constructed a concrete example of a theory
| that's super deterministic in a way that violates the bell
| inequalities but is complex enough to contain Turing machines
| driving the tests?
|
| The requirement that you can encode Turing machines might sound
| silly but I really think it's the core of the issue. The
| ability to make computers implies a certain level of hard-to-
| control due to the existence of things like the halting problem
| and pseudo random number generators and cryptographic hash
| functions.
|
| My understanding is that super determinism is one of those
| loopholes where it's easy to say its a problem, but actually
| providung a plausible concrete model where it's a problem is
| very hard.
| q-big wrote:
| > Have people actually constructed a concrete example of a
| theory that's super deterministic in a way that violates the
| bell inequalities but is complex enough to contain Turing
| machines driving the tests?
|
| I am not aware that such a theory exists, but the Nobel
| laureate Gerard 't Hooft made some possible first baby steps
| into this direction:
|
| Gerard 't Hooft; The Cellular Automaton Interpretation of
| Quantum Mechanics
|
| > https://link.springer.com/book/10.1007/978-3-319-41285-6
| abdullahkhalids wrote:
| Turing machines will exist in even very simple universes,
| because they are very simple. Instead physicists usually use
| complexity theory to analyze any proposed new universe or a
| theory for our universe. If for example, the new theory
| ensures P=NP, then is suspect. There is a lot of work done on
| this, but I don't know a good reference off the top of my
| head.
|
| However, sometimes, people do think about Turing Machines.
| Here is one paper by Scott Aaronson
| http://www.scottaaronson.com/papers/ctchalt.pdf
| kryptiskt wrote:
| Superdeterminism is unscientific as it's utterly untestable.
| It's a cop-out.
| naasking wrote:
| > Superdeterminism is unscientific as it's utterly
| untestable. It's a cop-out.
|
| Every interpretation of quantum mechanics is utterly
| untestable, or more precisely, each one is exactly as
| testable as every other interpretation because they all
| explain the data equally. That's why they're
| "interpretations".
| aqme28 wrote:
| Weird thing to comment on the Nobel prize announcement for
| QM experimentalists.
| naasking wrote:
| People have a weird understanding of quantum mechanics
| and their interpretations.
| A_D_E_P_T wrote:
| It's untestable by the definition of the term
| "superdeterminism" and the meaning of what it implies -- just
| as "1 + 1 = 3" is something that cannot make sense, by the
| very definition and meaning of its symbols.
|
| But this doesn't make it wrong. Superdeterminism is a very
| neat way of resolving physical paradoxes, such as the
| Wigner's Friend paradox: Any experimenter's decision to take
| a measurement of a certain physical phenomenon is
| predetermined by events, so the experimenter can attain no
| outcome but the one he does eventually attain, and nothing is
| in superposition. Neither Heisenberg's uncertainty principle
| nor Bell's inequality render this condition impossible, as
| Bell himself was well aware.
| simiones wrote:
| Not necessarily. In principle, there could exist a super-
| deterministic theory that predicts phenomena that QM does
| not. None has been invented so far, but in general the idea
| of super-determinism has received little attention, so that
| is not surprising.
|
| This may (or may not) change with work by Gerard t'Hooft and
| others.
| q-big wrote:
| > Superdeterminism is unscientific as it's utterly
| untestable.
|
| The same objection can be stated for the many-worlds
| interpretation of quantum mechanics:
|
| > https://en.wikipedia.org/wiki/Many-worlds_interpretation
| kgwgk wrote:
| Not sure if you're defending the former or attacking the
| latter...
| q-big wrote:
| I cannot understand why superdeterminism is so much
| frowned upon while the many-worlds interpretation is
| considered to be perfectly fine.
|
| I rather think the same standard should be applied to
| both.
| n4r9 wrote:
| One key difference is that many-worlds is an
| interpretation of quantum theory, whereas super-
| determinism refers to a class of physical theories with
| no known plausible examples.
| kgwgk wrote:
| MWI is more suggestive to pop-sci readers and ill-defined
| enough to mean different things to different people, I
| guess.
| Strilanc wrote:
| I won't defend popsci presentations, but formally MWI is
| pretty precisely defined. It's defined by assuming the
| postulates of quantum mechanics without including the
| Born rule. States are unit vectors, operations are
| unitary matrices, systems combine using the tensor
| product. That's many worlds.
|
| It's sort of like constructivist mathematics in that it
| involves dropping an extremely useful axiom, and then
| rederives basically all the same results in a more
| roundabout way.
| kgwgk wrote:
| If the "precise definition" of MWI doesn't go beyond "QM
| mathematical formalism when you get rid of its link with
| the physical world" what's the use of it?
|
| https://www.quantamagazine.org/why-the-many-worlds-
| interpret...
|
| "Attempts to explain the appearance of probability within
| the MWI come down to saying that quantum probabilities
| are just what quantum mechanics looks like when
| consciousness is restricted to only one world. [...] What
| the MWI really denies is the existence of facts at all.
| It replaces them with an experience of pseudo-facts (we
| think that this happened, even though that happened too).
| In so doing, it eliminates any coherent notion of what we
| can experience, or have experienced, or are experiencing
| right now. We might reasonably wonder if there is any
| value -- any meaning -- in what remains, and whether the
| sacrifice has been worth it."
| Strilanc wrote:
| Why are you assuming that measurement is the link between
| quantum mechanics and the real world? Quantum mechanics
| doesn't need to be linked to the real world, it _is_ the
| real world.
|
| That quote is simply wrong when it says that MWI
| "restricts consciousness to one world". As a simple
| matter of calculation, you can work out what MWI predicts
| a complex agent will report as its experience. Here for
| complex agent I want you to picture a computer program
| recording events and accumulating statistics, not a
| person, just because it makes the thinking clearer.
| Anyways, the prediction is that the recordings will be
| consistent with a classical type view, for lack of a
| better word, as opposed to a superposition of
| experiences. Even if the computer program was in fact run
| in superposition and interacted with superposed objects.
|
| But this is not surprising, because we already know that
| all the interpretations of quantum mechanics give the
| same predictions. So of course many worlds is not going
| to disagree with collapse type theories on what people
| say they experience. Because it is mathematically
| equivalent to the others. Observationally
| indistinguishable.
| q-big wrote:
| > Because it is mathematically equivalent to the others.
| Observationally indistinguishable.
|
| By Occam's Razor, if there exist multiple theories that
| are indistinguishable, we should take the one that has
| minimal assumptions (i.e. no assumption of the existence
| of some "multiverse" like in the many worlds
| interpretation).
| kgwgk wrote:
| I didn't even say "real world", I said "physical world".
| Physics, unlike mathematics, is an experimental science.
|
| Edit: where does the MWI define "complex agent" and
| "experience", by the way? I thought that MWI was
| precisely defined by assuming the postulates of quantum
| mechanics without including the Born rule, but it seems
| that there may be more to it!
| cedilla wrote:
| Superdeterminism isn't a theory, it's more of a choice of
| assumptions that could lead to a local hidden variable theory.
| No convincing model has been proposed thus far.
|
| Other such assumptions that would allow local hidden variable
| theories are "a wizard did it" and the rejection of the
| principle of relativity. All three share that they have no
| convincing reasoning behind them and that they are largely
| incompatible with our model of falsifiable science.
| solarist wrote:
| Sabine Hossenfelder had predicted the winners just last year:
| https://www.youtube.com/watch?v=jNT9Hn-96rM&t=619s
| [deleted]
| benrapscallion wrote:
| The Nobel citation reads as if John S. Bell should've gotten the
| prize
| n4r9 wrote:
| According to Wikipedia, Bell may well have done if he'd lived a
| little longer:
| https://en.wikipedia.org/wiki/John_Stewart_Bell#Death
| frontman1988 wrote:
| Never heard of any of them until now, looks phenomenonal work
| that I don't even understand lol. I just had a morbid though
| related to this. It's interesting how even the best of the
| scientists of our times will just be forgotten names in the long
| term history. Even among the greatest scientists only a few names
| like Einstein, Tesla or Newton remain in public memory, rest are
| never even known. If you want history to remember you, being even
| the best scientist in the world isn't enough. Shows how
| inconsequential the average man is in the big picture.
| xwolfi wrote:
| Aspect is semi famous in France, does a lot of conferences on
| his early work introducing quirky experiments showing
| unintuitive behaviours of quantum physics (present interactions
| can influence past "path" (there is no actual path until final
| collapse but the choice could only have been made before the
| observation... however the observation was random so how did
| the particule "know") taken by a wave-particule, I wished there
| were more english translation of his conferences cause it's
| mind bending)
| kgwgk wrote:
| For those interested in following a Quantum Optics course of
| his: https://www.coursera.org/instructor/~6471336
| bumby wrote:
| Oliver Burkeman created a term called "Cosmic Insignificance
| Therapy" that is related to this realization.
|
| _" ...it comes as a relief to be reminded of your
| insignificance: it's the feeling of realizing that you'd been
| holding yourself, all this time, to standards you couldn't
| reasonably be expected to meet. And this realization isn't
| merely calming but liberating, because once you're no longer
| burdened by such an unrealistic definition of a "life well
| spent," you're freed to consider the possibility that a far
| wider variety of things might qualify as meaningful ways to use
| your finite time. You're freed, too, to consider the
| possibility that many of the things you're already doing with
| it are more meaningful than you'd supposed--and that until now,
| you'd subconsciously been devaluing them, on the grounds that
| they weren't "significant" enough. (Burkeman 2021, p 212)"_
| e12e wrote:
| Interesting take, and somewhat at odds with Douglas Adams in
| Hitchhiker's Guide:
|
| > The Total Perspective Vortex derives its picture of the
| whole Universe on the principle of extrapolated matter
| analyses.
|
| > To explain -- since every piece of matter in the Universe
| is in some way affected by every other piece of matter in the
| Universe, it is in theory possible to extrapolate the whole
| of creation -- every sun, every planet, their orbits, their
| composition and their economic and social history from, say,
| one small piece of fairy cake.
|
| > The man who invented the Total Perspective Vortex did so
| basically in order to annoy his wife.
|
| > Trin Tragula -- for that was his name -- was a dreamer, a
| thinker, a speculative philosopher or, as his wife would have
| it, an idiot.
|
| > And she would nag him incessantly about the utterly
| inordinate amount of time he spent staring out into space, or
| mulling over the mechanics of safety pins, or doing
| spectrographic analyses of pieces of fairy cake.
|
| > "Have some sense of proportion!" she would say, sometimes
| as often as thirty-eight times in a single day.
|
| > And so he built the Total Perspective Vortex -- just to
| show her.
|
| > And into one end he plugged the whole of reality as
| extrapolated from a piece of fairy cake, and into the other
| end he plugged his wife: so that when he turned it on she saw
| in one instant the whole infinity of creation and herself in
| relation to it.
|
| > To Trin Tragula's horror, the shock completely annihilated
| her brain; but to his satisfaction he realized that he had
| proved conclusively that if life is going to exist in a
| Universe of this size, then the one thing it cannot afford to
| have is a sense of proportion.
|
| - Douglas Adams, Hitchhiker's Guide to the Galaxy
| Whatboard wrote:
| Relatability. Pretty difficult to be memorialized if the
| average person cannot understand or identify with your work.
| Perhaps we can either be more forgiving of the burdens and
| limitations the average person carries, so far removed from
| quantum effects and scientific prizes.
| sixQuarks wrote:
| If you want to be remembered in history, it's much easier to be
| a mediocre sports athlete than to be the best scientist who
| actually helps humanity. We are a ridiculously stupid species
| Vt71fcAqt7 wrote:
| >We are a ridiculously stupid species
|
| Can you explain what you mean by this?
| zethus wrote:
| Not the OP of the comment, but seemingly a common point of
| view that the most noble (and in some cases only valid?)
| pursuit of the human species is science/technology. I do
| find it interesting of the comparison between "mediocre
| sports athlete" and "best scientist" from the lens of aid
| to humanity. One could make an equally valid argument that
| a mediocre sports athlete brings more immediate utility to
| people in terms of entertainment, inspired hope, economic
| spend. In short, value is relative. Being a mediocre
| professional athlete is still a tremendous achievement. If
| your goal is to be remembered, you must appeal to the
| masses. Doesn't mean our species is stupid, it just means
| we are social.
| asdff wrote:
| Who you are remembered by is the context. A lot of people
| like keeping up with sports so thats why they know this
| trivia. OTOH scientists in field X will know of all the
| seminal work in their field. You can make a big impact in the
| field and be totally unknown outside of it, most scientists
| probably prefer it that way.
| seydor wrote:
| Not true really; name an athlete from the 1400s.
| leoc wrote:
| I can name a pro athlete from the 1100s and 1200s, at
| least: https://en.wikipedia.org/wiki/William_Marshal,_1st_E
| arl_of_P... ! Not disputing your point though.
| bumby wrote:
| Or maybe what's stupid is to set a goal to be remembered in
| history in the first place :)
| Arrath wrote:
| Agreed. I'm not too concerned with being remembered by
| history or not, I am content in having chosen to do good
| with my time here.
| sonofaragorn wrote:
| it's even easier to do somethign atrocious like being a
| serial killer
| kronix wrote:
| Well you're remembered for having an immense impact for
| generations to come, not necessarily winning an award. Einstein
| is remembered for transforming physics, not winning the Nobel.
| Just like MLK is remembered for the civil rights movement not
| winning the Nobel peace prize.
| pyuser583 wrote:
| Some folks are remembered just for the Nobel. Elias Canetti
| comes to mind - his only meaningful work was non-fiction, and
| therefore didn't qualify.
|
| Winston Churchill is the similar ... remembered as a
| political leader, but won the Nobel in Literature, not Peace.
|
| Einsteins Nobel was for Brownian motion, which isn't what
| pops to mind when you think "Einstein."
| kgwgk wrote:
| > Einsteins Nobel was for Brownian motion
|
| "for his services to Theoretical Physics, and especially
| for his discovery of the law of the photoelectric effect"
| stared wrote:
| I created an interactive simulation of the Bell inequality
| violation (Clauser-Horne-Shimony-Holt form):
| https://lab.quantumflytrap.com/lab/bell-inequality
|
| Enjoy!
| LatteLazy wrote:
| That's a pretty huge experimental success: quantum mechanics is
| truly probabilistic, not just deterministic but based on some
| hidden variable we haven't (or cannot) found.
|
| Have I understood it correctly?
| hackandthink wrote:
| I like the essence of Quantum Strangeness here:
|
| "To be more precise, what we shall show is that the particles'
| response* to a certain type of experiment is not determined by
| the entire previous history of that part of the universe
| accessible to them."
|
| John Conway, Simon Kochen: Free Will Theorem
| https://arxiv.org/abs/quant-ph/0604079
| zmgsabst wrote:
| > Why do we call this result the Free Will theorem? It is
| usually tacitly assumed that experimenters have sufficient
| free will to choose the settings of their apparatus in a way
| that is not determined by past history. [...]
|
| > We consider experimenters A and B performing the pair of
| experiments described in the TWIN axiom on separated twinned
| particles a and b, and assert that the responses of a and b
| cannot be functions of all the information available to them.
|
| I don't get it -- this sounds like they assumed their
| conclusion.
|
| There's also a couple places they make strong assumptions
| about information geometry I'm not sure I agree with --
| namely, if you want to refute modern Bohm-inspired models,
| you need to account for radically non-Euclidean spacetime.
| (Where you have a much harder time with "space like
| separated".)
|
| > FIN is not experimentally verifiable directly, even in
| principle (unlike SPIN and TWIN3).Its real justification is
| that it follows from relativity and what we call "effective
| causality," that effects cannot precede their causes. [...]
|
| > Not all information in the universe is accessible to a
| particle a. In the light of FIN, information that is space-
| like separated from a is not accessible to a. The information
| that is accessible to a is the information in the past light
| cone of a.
| simiones wrote:
| Not exactly - they expressed an assumption that is too
| strong in this explanation. The assumption that is needed
| is only that measurement choice is not correlated with the
| generation of the particles themselves - not that it is not
| determined by past history.
|
| That is why there was a lot of interest in doing cosmic
| Bell-like experiments: it is very hard to define a
| mechanism whereby the hidden property of the particle that
| left the quasar many billions of years ago also determined
| that Alice and Bob would set their apparatuses to measure
| these specific angles today. Theoretically this doesn't
| rule out the possibility, but it does mean at least that
| the theory would have to be significantly non-intuitive in
| its own right (whereas if Bell-like inequalities only
| happened for small-scale experiment, the theory that
| explained them _could_ have been very simple indeed - such
| as some new wave that affected the measurement apparatus or
| some aspect of how we choose measurement angles).
| zmgsabst wrote:
| But isn't the Bohm model that all particles are weakly
| correlated? -- eg, there's some kind of "whole universe"
| quasi-particle from the inflationary period?
|
| The exact alternative to non-determinism is super-macro
| quasiparticles/correlations. Which this seems to assume
| away.
| simiones wrote:
| There is a difference between proving that all events
| have share a causal relationship (which is an assumption
| of every mechanistic model of the universe), and proving
| that that causal relationship between distantly related
| events determines very precise restrictions that happen
| to match the predictions of QM.
|
| To take it to a more human realm - we can all agree that
| if Caesar weren't killed by Brutus, the world would be so
| different that it's very unlikely both Biden and Putin
| would be presidents of their respective countries today -
| this is an almost trivially true statement I would argue.
| However, if we observe that at every public appearance
| Biden and Putin wear costumes of the same color, it's
| very hard to come up with a theory that explains that
| their choice of costume is caused by Caesar killing
| Brutus.
|
| And this is essentially what the super-determinism
| argument gets at: the same thing that caused this photon
| emitted by a quark to be polarized up 1 billion years
| after the Big Bang _also_ caused Alice to measure the
| polarization of that particle along 30 degrees 13 billion
| years after the Big Bang.
| zmgsabst wrote:
| But they're carrying shared quantum state -- why would it
| be surprising their actions were correlated?
|
| Eg, that particle being a particular state is correlated
| to Alice picking a particular measurement because the
| total system must maintain that quantum number. The
| particle which emitted the photon and the particles which
| give way to Alice have carried that information since the
| inflationary period -- and so the photon and Alice share
| that correlation now.
|
| The conclusion seems to be "the correlation must be at
| least this old!" -- but that's exactly the claim being
| made.
|
| So I'm not sure I understand the problem for Bohm-derived
| models.
| shellac wrote:
| That is a lovely way of putting it. (I wish they'd never
| mentioned 'Free Will' since people get hung up on that)
|
| Always keep in mind that Bell himself was quite a fan of
| Bohm's theory, which is the canonical hidden variable theory
| really. The question becomes one of characterising that
| 'strangeness': is it the violation of locality ('that part of
| the universe accessible to them'), is violating outcome
| independence palatable, but not parameter independence (this
| was Shimony's idea originally)? Lots of curious stuff.
| lucozade wrote:
| As I understand it, Bell showed that, if quantum mechanics is
| correct, then any deterministic hidden variable theory would
| either have to be non-local or non-causal.
|
| Aspect et al demonstrated experimentally that quantum mechanics
| is correct in the Bell sense.
| GolDDranks wrote:
| You understood correctly that quantum mechanics cannot be based
| on some hidden variable we haven't or cannot find. (Edit: oops,
| I re-read your comment and it seems you say the exact opposite
| thing? The point is that Bell's theorem rules hidden variables
| OUT. Here's an easily digestible video about this:
| https://www.youtube.com/watch?v=ZuvK-od647c )
|
| About probability: no one knows. It might be that there is a
| "wave function collapse" that has a probabilistic outcome. But
| it might be that there is no such a thing. Quantum mechanics
| that remain in the "quantum" realm are not probabilistic, it's
| only when you cross over to the classical world.
|
| So it might be equally well, that the Everett interpretation
| (so-called "many worlds interpretation") is true, and the
| probability is something physicist Sean Carroll calls "self-
| locating uncertainty":
| https://www.preposterousuniverse.com/blog/2014/07/24/why-pro...
| That is, there are multiple "yous" that experience different
| outcomes, and you don't know which branch of the wavefunction
| you find "yourself" in, which "you" you are.
| twawaaay wrote:
| > You understood correctly that quantum mechanics cannot be
| based on some hidden variable we haven't or cannot find.
|
| That's not true. The only thing we know is that the above
| _appears_ to be true, but since we do not actually know the
| mechanism behind quantum mechanics we will be in this limbo
| until (if ever) we find the actual rules.
| n4r9 wrote:
| Actually, the power of Bell's theorem is that it applies to
| _any_ physical theory which attempts to explain observed
| correlations in experiments on entangled particles. It
| really does say "No matter what's behind quantum theory,
| we know it isn't like this".
|
| I do have a small gripe with the above comment, in that
| Bell's theorem only rules out _local_ hidden variables.
| Some take the view that Bohmian mechanics is an formulation
| of quantum theory which employs hidden variables, just
| explicitly non-local ones.
| q-big wrote:
| > I do have a small gripe with the above comment, in that
| Bell's theorem only rules out _local_ hidden variables.
| Some take the view that Bohmian mechanics is an
| formulation of quantum theory which employs hidden
| variables, just explicitly non-local ones.
|
| Superdeterminism also allows local hidden variable theory
| without violating Bell's theorem:
|
| > https://en.wikipedia.org/wiki/Superdeterminism
|
| A 2013 interview with the Nobel Laureate Gerard 't Hooft
| on this topic:
|
| > https://spookyactionbook.com/2013/10/07/does-some-
| deeper-lev...
|
| A paper by Sabine Hossenfelder and Tim Palmer:
|
| Sabine Hossenfelder and Tim Palmer; Rethinking
| Superdeterminism
|
| > https://www.frontiersin.org/articles/10.3389/fphy.2020.
| 00139...
|
| In 2016, 't Hooft published a textbook on some specific
| points of superdeterminism:
|
| Gerard 't Hooft; The Cellular Automaton Interpretation of
| Quantum Mechanics
|
| >
| https://link.springer.com/book/10.1007/978-3-319-41285-6
| n4r9 wrote:
| It's true in a sense that you can get around Bell's
| theorem by supposing that Alice and Bob's mesasurement
| choices are strongly pre-correlated in a specific way.
| But then I feel you end up with this sort of bizarre
| universal conspiracy set up just to make humans believe
| in quantum theory.
| q-big wrote:
| If you have such an objection, you might be interested in
| section 4 (in particular section 4.1 and 4.2) of the
| linked paper
|
| Sabine Hossenfelder and Tim Palmer; Rethinking
| Superdeterminism
|
| > https://www.frontiersin.org/articles/10.3389/fphy.2020.
| 00139...
| n4r9 wrote:
| > Bell's and similar examples that rest on arguments from
| fine-tuning (or sensitivity, or conspiracy) all
| implicitly assume that there is no simple way to
| mathematically express the allowed (or likely) initial
| states that give rise to the predictions of quantum
| mechanics.
|
| I mean, this is the crux of it. You'd have to have some
| convincing way of explaining why states "give rise to the
| predictions of quantum mechanics" for all possible
| measurement choices yet to be made by anyone. It still
| feels conspiratorial to me, having read that whole
| section! If someone were to show me a simple mathematical
| expression as defined above, I would be open to it. As
| far as I can tell, all this article is saying is "
| _maybe_ it 's possible".
| q-big wrote:
| > If someone were to show me a simple mathematical
| expression as defined above, I would be open to it. As
| far as I can tell, all this article is saying is "maybe
| it's possible".
|
| Finding such a simple mathematical expression is exactly
| what research into this direction is for. But obtaining
| such is rather the _end result_ that one hopes for.
| n4r9 wrote:
| Sure. It's a fine and noble goal, but at this point it
| just looks... well, as the Wiki article you linked says,
| "as plausible, and appealing, as belief in ubiquitous
| alien mind-control".
| [deleted]
| heckerhut wrote:
| But there are constraints on those hidden mechanics as
| well. Not sure hidden variables theory survives these
| constraints. Can someone more knowledgeable talk on this?
| DebtDeflation wrote:
| QM can't be based on LOCAL hidden variables. Hidden variables
| theories that are explicitly nonlocal are not ruled out.
| Separately, Superdeterminism eliminates both the requirement
| for nonlocality and the result that QM is inherently
| probabilistic.
| q-big wrote:
| > QM can't be based on LOCAL hidden variables.
|
| ... as long as we assume that the system being measured is
| uncorrelated with the choices of which measurements to make
| on it. :-)
| rmu09 wrote:
| Superdeterminism eliminates any requirement(s).
| [deleted]
| himinlomax wrote:
| Aspect's experiment dates from the early 1980s, that's a long
| time coming!
| eternalban wrote:
| Congratulations to Alain Aspect. Long time coming, well deserved.
| walnutclosefarm wrote:
| Its about time they recognized Zeilinger's work - he's been doing
| astonishing work clarifying and articulating the foundations of
| Quantum Mechanics for decades.
| maxnoe wrote:
| The guy presenting the topic called Erwin Schrodinger "Edwin",
| both in writing on his slides and verbally.
|
| I was bewildered to see a blunder of that magnitude in the
| official nobel presentation...
| Nokinside wrote:
| There is even bigger mistake:
|
| >The Nobel Committee makes a common mistake in the press
| release, implying that Bell rules out hidden variables. It's
| only _local_ hidden variables that are ruled out (absent
| superdeterminism). Bell was a big supporter of Bohmian non-
| local hidden variables!
|
| from Sean Carroll
| https://twitter.com/seanmcarroll/status/1577254806208798722
| lioeters wrote:
| From another tweet of his:
|
| Bell on Bohm - Sheldon Goldstein -
| https://sites.math.rutgers.edu/~oldstein/papers/bb.pdf
| bowsamic wrote:
| Why is that a blunder of any important magnitude? As a
| physicist I do not think so. It's actually pretty common to
| make mistakes like that in physics. And physicists are not
| particularly careful about their presentations, even very
| important ones. We don't have the sense to care much about this
| things. "Official Nobel presentation" is still seen as "just a
| talk"
| maxnoe wrote:
| Not the reaction I got from my colleagues, they were all just
| like "WTF, how can _this_ happen? "
| SiempreViernes wrote:
| Were they all German Physicists? Leave Hans alone, he's
| chill.
| alephu5 wrote:
| Did you add a typo as a joke?
| hwestiii wrote:
| Someone's job in PR is to get the facts right in the press
| releases. Like referring to first American President as
| "Gerald Washington"
| bowsamic wrote:
| Was there a PR person to vet this presentation?
| rerx wrote:
| Clauser and Aspect did their experiments in the early 1970s and
| 1980s. That's a crazy long wait!
| c7b wrote:
| There's a quote, I believe by an economics Nobel (memorial)
| prize winner, that goes like "It's a strange feeling to be
| honored in your 80's for work that you've done in your 20's" -
| couldn't find who said it after a bit of searching
| fabatka wrote:
| In uni I remember one of my professors telling us that the time
| gap between the awarding of the Nobel prize and the discovery
| for which it is awarded keeps getting longer (he was talking
| specifically about physics). I remember he also lamented George
| Gamow never getting a Nobel prize. (edit: grammar)
| efsavage wrote:
| This is sad, IIRC the goal (and reason it only goes to living
| people) is to throw good money after good, in the hopes of
| more to come, not simply reward past advances and fund
| retirements.
| tokai wrote:
| The goal was to rub Nobels reputation clean with the
| reputations of great living scientists.
| leoc wrote:
| That's definitely the main cause, but in the case of Clauser
| at least there's the added wrinkle that for the first few
| years his work wasn't very popular with other physicists. His
| PhD advisor was writing recommendation letters specifically
| telling people not to hire Clauser for work on QM
| experiments:
| https://arxiv.org/ftp/physics/papers/0508/0508180.pdf .
| GistNoesis wrote:
| I'm not convinced. (But also I'm not a physicist).
|
| Don't get me wrong, they are all great experimentalists and their
| experimental work helped move the science forward in the
| understanding and control of the atomic scale.
|
| But their "Bell's experiment" variations have been used to
| "disprove" and cast aside wide branches of theoretical research,
| and this will probably remain as one of the biggest failure of
| modern science.
|
| If you model the experimental settings in your theory, it's
| indeed quite simple to reproduce the QM probabilities (and
| therefore violations of CHSH inegalities), with a local hidden
| variable theory.
|
| In fact here is 60 lines of numpy code to set-up virtual
| experiments to convince yourself (try various settings for the
| polarisers angles alpha and beta)
| https://gist.github.com/unrealwill/2a48ea0926deac4011d268426...
| (Straight implementation of Marian Kupczynski "Closing the Door
| on Quantum Nonlocality" https://www.mdpi.com/1099-4300/20/11/877
| (around eq.7-8) if you need more explanation).
| Strilanc wrote:
| Your code is not properly enforcing the communication
| constraint between the two players. Try to enter code that
| passes the bell tester widget included in this blog post and
| you'll find the problem:
|
| https://algassert.com/quantum/2015/10/11/Bell-Tests-vs-No-Co...
| GistNoesis wrote:
| Of course it can't be written into your bell tester.
|
| It's not hiding anything. It works because of the post-
| selection. But this selection is done in a locally compatible
| way.
|
| It works because you as the (virtual) experimenter can
| specify/choose explicitly a precise definition of what a
| measurement is, (which you can't do in your widget).
|
| My code is showing an example of the general structure of how
| you could/should define what a measurement is, in such a way
| that you preserve both the locality of the world, and the
| observed violation of the Bell inequalities (according to
| your definition of what a measurement is).
|
| I'd argue that it's in essence doing what, one way or the
| other, the real world measurement apparatuses of the
| experimenters are doing.
| enviclash wrote:
| I am also not an expert on the topic, but citing a MDPI paper
| to argue against a Nobel prize seems also unconvincing.
| AkshatM wrote:
| > it is indeed quite simple to reproduce ... with a local
| hidden variable theory
|
| This is not the whole truth. Bell's inequality assumes a few
| reasonable assumptions for hidden variable theories besides
| locality (https://plato.stanford.edu/entries/bell-theorem/) and
| it is true that sacrificing these assumptions can yield a local
| hidden theory consistent with Bell's inequality / CHSH
| inequality violations.
|
| But the whole point of these assumptions is that we _want_
| them. Bell 's inequality is the definitive experimental test
| that a standard classical theory is not waiting in the wings
| for us, and those assumptions are central to classical
| mechanics.
|
| The issue with a theory that sacrifices things like parameter
| independence or similar is that they will remain mathematical
| curiosities, much like interpretations of quantum mechanics,
| because there is no way to test them. _And_ they 'd be stranger
| than quantum mechanics, so you don't get any relief either.
|
| So, yes, you can do this. But it has no practical value. This
| is not the experiment's fault in any way.
|
| However, if you are arguing that you can have a local hidden
| variable theory that satisfies _all_ of Bell 's assumptions and
| violates the inequality, then you have some severe issues in
| your argument somewhere, because it is categorically
| impossible.
|
| > 60 lines of numpy code
|
| In the event you are arguing for a local hidden variable theory
| that satisfies all of Bell's other criteria: firstly, there is
| no guarantee the simulation has any fidelity to the real world
| at all.
|
| Thankfully, you don't have to settle for simulation. I was
| fortunate to take 180Q at UCLA, an undergraduate class where we
| were required to derive the CHSH inequality and perform simple
| experimental violations by ourselves. The tools needed to run a
| simple test are commercially available and affordable - you can
| do it yourself at home.
|
| I was able to achieve experimental violation when I did so back
| in 2015/2016, and documented the results here:
|
| https://github.com/AkshatM/Physics180Q/blob/master/Final%20P...
|
| Of course, if you are arguing we can sacrifice an assumption of
| Bell's besides locality, then the above is moot. But it would
| still be rather pointless.
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