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The everything-is-a-quantum-wave interpretation of quantum physics
- sebzim4500 4y agoAFAICT he's arguing that the Many world's interpretation should be renamed to the "Everything-Is-A-Quantum-Wave" interpretation. I've heard people suggest "Universal wave function" interpretation, which IMO is better than either.
- mtlmtlmtlmtl 4y agoI like Sean Carroll's suggestion: Austere Quantum Mechanics. Because many worlds is really just taking the state of quantum mechanics and accepting what we do know about it without added assumptions. There's a wave function, it obeys the Schrödinger equation. Other interpretations always posit some extra stuff, like wave function collapse, or pilot waves. Many Worlds just takes the Schrödinger equation seriously on its own. Therefore it is in a very real sense the most austere interpretation, even though it posits all those worlds.
- jakear 4y agoSee also: "The Zen Anti-Interpretation of Quantum Mechanics" https://scottaaronson.blog/?p=5359 https://scottaaronson.blog/?p=5359
- mtlmtlmtlmtl 4y agoLove me a good Scott Aaronson blogpost! I go back and forth myself on whether I buy the austere interpretation. Mainly I struggle with the open question of probabilities. Something about the combination of probability and philosophical argument - the two most hard to intuit things in the world - makes my head spin. Though there are also so many compelling advantages, like providing an arrow in time in that branches of the wave function never re-merge. I'm also fascinated by superdeterminism. I don't have the same philosophical issues with it that others have. I settled on the "useful fiction" view of free will a long time ago anyway. But I've yet to see any logic supporting the idea that the entire universe would, or even could conspire in this way. But I also used to think many worlds was inherently illogical, so I don't know. Then there's the voice in me that says "it's just a collapse, it just has to be when there's enough moving parts", but again, can't think of a justification for it other than intuition. And now there's a 4th shouting at me "why are you thinking about this, you're a programmer". I guess I'm just wired that way, I can't not ponder the things I don't understand, no matter how irrelevant they are to my life.
- jakear 4y agoTiger got to hunt, bird got to fly; Man got to sit and wonder 'why, why, why?' Tiger got to sleep, bird got to land; Man got to tell himself he understand. ― Kurt Vonnegut, Cat's Cradle
- jemmyw 4y agoI find super determinism fascinating too. It's not really scientific because it's ultimately untestable. I just like the idea that the universe is whole, compete from end to end and time is just another axis through it. In my interpretation I'm not traveling through time but just exist in each moment of time thinking that I'm traveling through it because I remember the last moment. It's not a belief, just a thought.
- galaxyLogic 4y ago> There's a wave function, it obeys the Schrödinger equation." Or perhaps more precisely: "There is no wave function. The wave-function we talk about is just a mathematical recipe for computing the expected test-observations". Functions are abstract things, they don't exist in the physical world. They only describe the physical world, at best. So that really leaves the question why do our measurement results follow the predictions of the wave-function unanswered. I think we would like to come up with some theory of why the wave-function so closely predicts our observations.
- jakear 4y agoHow can you know there's not a Universal Quantum Turing Machine that has encoded precisely the functions we've discovered based on the test-observations we've conducted? And if there is, would the question "why" anything occurs be well defined? It does what it does because it was constructed to do so.
- resource0x 4y agoWhat hardware does this Turing Machine run on?
- jakear 4y agoIt's all in your head.
- BadThink6655321 4y agoEarlier today I came across this on Scott Aaronson's site: "Also, are the ultimate equations that govern the universe “real,” while tables and chairs are “unreal” (in the sense of being no more than fuzzy approximate descriptions of certain solutions to the equations)? Or are the tables and chairs “real,” while the equations are “unreal” (in the sense of being tools invented by humans to predict the behavior of tables and chairs and whatever else, while extraterrestrials might use other tools)? Which level of reality do you care about / want to load with positive affect, and which level do you want to denigrate?" https://scottaaronson.blog/?p=3628 https://scottaaronson.blog/?p=3628
- Jensson 4y ago> Therefore it is in a very real sense the most austere interpretation, even though it posits all those worlds. I strongly disagree. Wave function collapse is the best description for a randomized phenomena we can observe. That exact same phenomena exists in many worlds as well, just that many worlds invent whole different universes to try to get away from the fact that to us the event is random. So instead of saying "our universe is random" you say "Our universe is not random, we just observe a random part of the universe and can never observe the real whole part of it", that isn't solving anything at all, its just a more elaborate way to say "the universe is random".
- mort96 4y agoWave function collapse is an additional mechanism. If you remove the wave function collapse, you get many worlds.
- Jensson 4y agoBut we observe a random phenomena and call that wave function collapses, we don't observe many worlds. Many worlds is outside of observation, it is an additional feature of the universe that isn't based on any observations.
- mort96 4y agoI mean you're right of course, if this was easily experimentally testable we would've done so already. So we're left to choose between two theories: one in which the rules for macro systems and quantum systems are completely different and quantum systems collapse into a state consistent with the rules for macro systems when they interact with a macro system -- and one where there is only the one set of rules and no collapse. That doesn't mean you should choose to believe one or the other, but it means that one model requires fewer mechanisms than the other. At least that's my understanding.
- Jensson 4y ago> one in which the rules for macro systems and quantum systems are completely different and quantum systems collapse into a state consistent with the rules for macro systems when they interact with a macro system That is wrong, quantum state collapse just makes the quantum wave take the shape of another quantum wave, nothing in it requires it to be related to macro state nonsense like pointwise particles etc. If that is the reason you don't like wavefunction collapse then you just misunderstood quantum mechanics basics, all wave function collapse is is that it is a rule for how quantum waves can transform, there is nothing about it that connects it to our macro world view. > and one where there is only the one set of rules and no collapse. MWI still has wave function collapse, the "we observe random part of the universe" part is the wave function collapse, that remains unexplained, why do we only see a random subset? You can't explain that. Many worlds make it harder to see that this part is unexplained, that makes it strictly worse as an interpretation in my opinion.
- zackees 4y ago[dead]
- ummonk 4y agoI like to call it the Universal Wavefunction, or Everettian theory. The splitting into many worlds is just a side effect. That said, any discussion of this theory should mention the rather puzzling issue that gravitation is nonlinear, and thus it would be impossible for there to be a superposition of worlds in each of which general relativity works as observed.
- d_tr 4y ago> That said, any discussion of this theory should mention the rather puzzling issue that gravitation is nonlinear, and thus it would be impossible for there to be a superposition of worlds in each of which general relativity works as observed. Are such superpositions not a thing in String Theory? How would gravity's nonlinearity preclude this? Quantum mechanics works fine with nonlinear systems like weird oscillators.
- ummonk 4y agoRe-reading my comment, I shouldn’t have said “impossible”. Yes, any theory that successfully quantizes gravitation will allow superpositions of gravitational worlds. String theory likely does this, though some will quibble with the phenomelogy as to whether it reproduces general relativity as we know it.
- resource0x 4y agoNone of the interpretations I heard of addresses a simple question: why don't we see hibbles and glorphs? For the context, please refer to an old article by Matthew Cook: http://www.paradise.caltech.edu/~cook/Workshop/Physics/QMQuestion.html http://www.paradise.caltech.edu/~cook/Workshop/Physics/QMQue...
- whatshisface 4y agoYou don't need an interpretation to address them. The design of the measurement apparatus is what defines the basis in which the system is most easily expressed, which you don't see when doing abstract quantum information calculations but you do see when you are talking about magnetic fields and particles that move through them. For example in the stern-gerlach apparatus, the alignment of the magnet is what determines the measurement basis.
- resource0x 4y ago"most easily expressed"? How does the nature know that it has to behave according to the rules "most easily expressed" by humans? Mathematically, all bases are equivalent (which is exactly what the author reminds us about in the very first paragraph).
- panda-giddiness 4y agoI don't think you really groked your parent's comment. Asking why we don't see |dead> + |alive> states is like asking why we don't measure states of definite Jx when measuring Jz -- you're simply measuring in the wrong basis. So why do we measure only states of |dead> or |alive>? I don't know; maybe it's evolutionarily advantageous (those simultaneously dead and alive beings sound quite bothersome). Regardless, it's irrelevant -- evidently we are only capable of making measurements in the basis {|dead>, |alive>}, so naturally that's all we'll ever see. Of course, that restriction by itself doesn't make the |dead> + |alive> state less real, only unobservable when you're coupled with the system.
- 4y ago
- MichaelRazum 4y agoFor the experts here. As far as I know Quantum Theory is described by a linear differential equation. How can it describe observed non linearity? The point was made by Sabine Hossenfelder
- sebzim4500 4y agoNot sure what you mean exactly? Nonlinearity in what? If you read an introductory textbook the first nontrivial quantum system you will study is the harmonic oscillator, which has potential V(x) ~ x^2.
- MichaelRazum 4y agoI mean the dynamics is driven by a linear operator. But you can observe objects that can't be described this way. I think Hossenfelder described it in the video the problematic in Chaos: The real problem with quantum mechanics
- sebzim4500 4y agoIs there somewhere I can read/learn about it somewhere else? I'd rather not watch Hossenfelder's videos, she seems to live in a different branch of the wave function from me where e.g. superdeterminism is a reasonable thing to study.
- vandahm 4y agoI didn't study physics in university, so please forgive this naïve question. Would an appropriate interpretation of quantum physics simply be that we don't have an interpretation of quantum physics? We have mathematical equations and observations that confirm the math, but it seems that we don't have observations that give credibility to one interpretation over the others. Instead of speculating, can't we just agree that we don't know? I'm not suggesting that we should do that -- I suspect that there's a lot that I'm missing. But I guess I don't understand why these speculative interpretations are so alluring if we can't confirm or invalidate them through experiments.
- mtlmtlmtlmtl 4y agoIt's a valid concern to be sure, and one with a lot of interesting historical background. Foundations of quantum mechanics was a taboo subject in physics ever since the Bohr-Einstein debates, and still is to this day, in some circles. And mosts physicists actually do this; they don't worry about intepretation of quantum mechanics in their work. They use the Schrödinger equation and the Born rule for their calculations and leave it at that. This is often referred to as "shut up and calculate". But the measurement problem, addressed through these interpretations is a foundational problem, and the tricky thing with those is you have no idea what the implications might be on other foundational problems. An understanding of the measurement problem may very well have something to say about other open questions like the arrow of time or quantum gravity. It could even have implications for the scalability of quantum computers. And I don't think it's fair to say that this question is empirically unanswerable. A number of possible interpretations have actually been ruled out by the bell inequality, for instance. And both theoretical and empirical research on this topic has seen a resurgence in recent decades. On a purely sociological basis I feel inclined to think that the reason the measurement problem has seemed so incalcitrant is not because it's fundamentally unsolvable, but because physics as a field has denied itself from actually trying to solve it, and actively pushed out those who dared work on it.