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Can the double-slit experiment distinguish between quantum interpretations?
- konschubert 4y agoI wish I could have studied Physics in 2050 when the Copenhagen Interpretation was already dead. Or maybe I should have stuck around to move the science along. I didn’t have the grit for that
- drowsspa 4y agoIf my experience in Physics is somewhat typical, it's barely taught as an interpretation, it's just as Feynman put it "shut up and calculate".
- konschubert 4y agoTrue. And I’m not saying we should be having philosophical discussions. But pretending that there isn’t a problem with the copenhagen interpretation is also an insult to the students intellect.
- analog31 4y agoWe were certainly more than aware of the problems. They even brought in colloquium speakers to talk about it.
- konschubert 4y agoI don't remember this being discussed at my alma mater. Not in lectures and not in colloquia. But then again, maybe it happened and I missed it. I don't want to throw shade.
- Nomentatus 4y agoHope you'll pardon my pedantry (I just got schooled on this): https://www.motleybytes.com/w/N_David_Mermin_quotes/Shut_Up_and_Calculate https://www.motleybytes.com/w/N_David_Mermin_quotes/Shut_Up_... What I like is that the first use was ironic, as he continues "But I won't."
- eternalban 4y ago[flagged]
- UseofWeapons1 4y agoFascinating. The summary: “On the one hand, according to the (generalized) standard canonical interpretation, the arrival distribution is considered as a generalized observable, which is described by a positive-operator-valued measure (POVM), satisfying some required symmetries [10, 11, 30, 31]. On the other hand, in the realistic- trajectory-based formulations of quantum theory, such as the Bohmian mechanics [32], Nelson stochastic mechanics [33], and many interacting worlds interpretation [34], the arrival time distribution could be obtained from particles trajectories [7, 18, 35, 36].” I’d be interested to hear a definition of each of those interpretations.
- User23 4y agoBohm is the pilot-wave theory[1]. [1] https://en.wikipedia.org/wiki/Pilot_wave_theory https://en.wikipedia.org/wiki/Pilot_wave_theory
- deleted 4y ago[deleted]
- ko27 4y agoIf this paper is correct and we can experimentally verify different QM interpretations, then this is really groundbreaking stuff. I wonder why this news isn't everywhere.
- danielam 4y agoA side note: Robert Koons at UT Austin has just published a book in which he examines the lesser known Aristotelian interpretation of QM. Here’s a short review of the book[0] (the book is quite cheap for the genre) and a lecture Koons gave last year. [0] https://www.thepublicdiscourse.com/2023/01/86512/ https://www.thepublicdiscourse.com/2023/01/86512/ [1] https://youtu.be/Mf-iVHgIz3E https://youtu.be/Mf-iVHgIz3E
- BadThink6655321 4y agoEdward Feser published a review of Koon's book ([0], [1]). I was struck by the number of times Feser argued that a "common sense" view of QM is the one that is "basically correct." Given the documented failures of common sense in mathematics and physics (see especially Feynman's comments in the first 15 minutes of [2]), why should anyone think common sense is a reliable metric to how things are? [0] https://www.thepublicdiscourse.com/2023/01/86512/ https://www.thepublicdiscourse.com/2023/01/86512/ [1] https://edwardfeser.blogspot.com/2023/01/koons-on-aristotle-and-quantum-mechanics.html https://edwardfeser.blogspot.com/2023/01/koons-on-aristotle-... [2]https://www.youtube.com/watch?v=41Jc75tQcB0 https://www.youtube.com/watch?v=41Jc75tQcB0
- derbOac 4y agoI have no idea what a common sense interpretation of QM would be. I'm having trouble locating what I'm thinking of but I thought it had been established that at least one of three very non-common-sense interpretations of QM had to hold at this point.
- danielam 4y agoThe article you provide a link to is the review I linked to (and that article mentions that Heisenberg was partial to the hylomorphist view of QM). > Given the documented failures of common sense in mathematics and physics [...], why should anyone think common sense is a reliable metric to how things are? I think the most serious objection is that categorical dismissal of common sense is a form of skepticism, and as a consequence, you undermine the very claims you are appealing to. All science takes place within a context and that context is going to be common sense, ultimately; the alternative is some truncation or corruption of it. So you might as well own it and own it to the fullest. All skepticisms suffer from the same problem, namely, the strange belief that you can know something while undermining the very conditions possibility of knowing it. Note that by "common sense", we mostly mean that we take the human apprehension of the world as basically accurate, even if it is fuzzy around the edges or needs correction or refinement [0]. So at the very least, I think that the presumption is in favor of common sense. Your question does not provide a reason for doubting common sense categorically or even rejecting common sense interpretations of QM. It is a better idea to engage with the proposed interpretation, to understand it, and make specific criticisms instead. [0] https://www.firstthings.com/web-exclusives/2012/10/aristotle-call-your-office https://www.firstthings.com/web-exclusives/2012/10/aristotle...
- chedca21 4y ago[flagged]
- elmomle 4y agoCould you explain the connection between these two statements?
- lucisferre 4y agoYes the OP doesn't understand the first one therefore the second one might be false. QED.
- rsstack 4y agoIf you see something absurd in a HN comment, it's worthwhile to check their comment history. You aren't missing anything or miscomprehending - it's just a troll.
- a257 4y agoHigh energy EM radiation is able to ionize atoms through the photoelectric effect. Cellphone radiation is unable to do this because it doesn't have enough energy. This is strictly the case because energy in these scales are quantized.
- red_trumpet 4y agoBy high energy you mean low wavelength, right? Because also large wavelengths could transmit a high amount of energy.
- PartiallyTyped 4y agoIf you don’t like the theoretical explanation given in the sibling comment regarding energy carried by photons, try an experimental approach and get back to us with your results.
- ajross 4y agoCan someone in the physics community give us the consensus summary of whether this is serious/real/non-BS? Seems like this would be an absolutely earth-shattering theory result (especially since they claim it's verifiable with a feasible experiment), which seems hard to judge from outside based on the paper itself. Are people buying this, or are there questions?
- scythe 4y agoIt's not earth-shattering for theory, I can tell you that for sure. If you read the citations of the paper, you'll find that Das, Nöth and Dürr already proposed something similar in 2019 which was published in Phys. Rev. A, one of the most respected journals. What these authors are doing is basically to propose a refined (and possibly more general) experimental setup. Whether this actually works out in practice, or even represents a particularly good way to go about it, is beyond my fluency in this field; I would guess the practical effect is incremental at best.
- ko27 4y agoIt's earth-shattering, because the current prevailing opinion in physics is that some of those QM interpretations are indistinguishable in reality and that their difference is only a matter of philosophy.
- sounds 4y agoI think what's being asked is if this is the best way to formulate a testable hypothesis. It seems to pass a first scan here.
- Vox_Leone 4y agoIt would seem to me that the sheer amount of observation on the macro scales has the effect of freezing the quantum observables in space and time, giving rise to the common, agreed-upon, reality. Seems like a solution to a problem. [edited for spelling errors]
- russdill 4y agoThe concept for this is called decoherence
- danbruc 4y ago[...] freezing the quantum observables in space and time [...] also sounds like the quantum Zeno effect [1] which is kind of the opposite of decoherence [2]. [1] https://en.wikipedia.org/wiki/Quantum_Zeno_effect https://en.wikipedia.org/wiki/Quantum_Zeno_effect [2] https://en.wikipedia.org/wiki/Quantum_decoherence https://en.wikipedia.org/wiki/Quantum_decoherence
- russdill 4y agoI think the parent is using the terms here in a very loose way and it's not trying to refer to the quantum zeno effect but rather the emergence of the classical world.
- Vox_Leone 4y agoYes, that is what I tried to convey: The emergence of the classical reality from quantum effects. Sorry for not having been clearer.
- chriswarbo 4y agoThat's usually referred to as 'decoherence' https://en.wikipedia.org/wiki/Quantum_decoherence#In_interpretations_of_quantum_mechanics https://en.wikipedia.org/wiki/Quantum_decoherence#In_interpr... (Observation can also literally freeze the state of a system, via the Quantum Zeno Effect https://en.wikipedia.org/wiki/Quantum_Zeno_effect https://en.wikipedia.org/wiki/Quantum_Zeno_effect but that's based on observing the same system over and over again, not different systems interacting)
- alberth 4y agoStill the best video I've ever found that describes the phenomenon of the double-slit experiment. Cartoon by "Dr Quantum" https://www.youtube.com/watch?v=Bq69-MI9TA0 https://www.youtube.com/watch?v=Bq69-MI9TA0
- deleted 4y ago[deleted]
- jjbinx007 4y agoOh god no. That video is very misleading and pretty much borders on pseudo-science. For starters it depicts photons as balls, when it would be much less confusing and more intuitive to instead think of them as waves with discreet energy amounts. If you think about it as a wave, what's happening is a wave with a photon-amount of energy passes through both slits which causes an interference pattern. When it hits the wall it coalesces into a single particle/dot. Also, it talks about 'observer' and strongly indicates the observer needs to be a conscious entity. Instead of observer, just use the word "detector", and bear in mind that detector interacts with the photon (whereas at the classical level you can watch or observe something without affecting the system).
- alberth 4y agoWould you mind linking to a better video, suitable for a general audience. The difficulty is most video are either way to technical or way too high-level.
- jjbinx007 4y agoI recommend videos by Arvin Ash. He's one of the few who manages to explain things in a way that makes sense to me. A lot of Youtube videos either parrot the pop-sci explanations I get tired of reading in magazines or they're way above my head.
- criddell 4y agoThe video talks about shooting electrons rather than photons through the slits. Does it matter what kind of particle you shoot through? If I fired a stream of hydrogen atoms or neutrons through the slit, would I get an interference pattern? I’ve also always wondered if it matters what side of the slits the detector is on? The experiment as depicted in that video has the detector on the gun side of the slits. Would you get the same thing if you moved it to the wall side of the slits? Also, does the wall itself count as a detector/observer?
- fredgrott 4y agoThat is about like saying photons can display quantum interpretations given that photons are the entities that interact with double slits in the first place. Or event to get more eccentric, your ocular lobes can interpret quantum because they receive photon interactions with the rod cells. Just pointing out the obvious problems with tongue-in-cheek.
- gumby 4y agoThe first author named on the paper is...interesting. A literal ghost writer.
- eternalban 4y agoYes, "interesting". A cry for help from Sharif University, perhaps. Ayatollah Ali Akbar Rafsanjani gave up the ghost rather 'unexpectedly'. Prior to his sudden removal from the scene he had made remarks regarding Japan, Germany, and their ultimate relationship with USA. He was an eminently pragmatic ideologue. This internal contradiction clearly proved to have had adverse health consequences. https://www.theguardian.com/world/2018/jan/09/iran-reopens-investigation-into-rafsanjani-death https://www.theguardian.com/world/2018/jan/09/iran-reopens-i... "Today, you can see that Germany and Japan have the strongest economies in the world. These same two countries were prohibited from having military forces after the Second World War. When a country is at war, it spends so much money on its military. With no military spending, these countries could use that extra money on science and production and were able to create a science-based economy for themselves. As a result, they are no longer fragile. The door has been opened to a similar process in Iran." https://www.al-monitor.com/originals/2016/09/ayatollah-hashemi-rafsanjani-japan-germany-military-spending.html https://www.al-monitor.com/originals/2016/09/ayatollah-hashe... Yes, you are correct to read that and understand the Ayatollah Rafsanjani was explaining the benefits for Islamic Republic to throw in the towel and join the ranks of former enemies now prosperous allies of US: Germany and Japan. https://www.newyorker.com/news/news-desk/rafsanjani-irans-wiliest-revolutionary-dies https://www.newyorker.com/news/news-desk/rafsanjani-irans-wi...
- mh7 4y agoIt's probably a case of me not knowing what I don't know, but I've never understood what the big deal with 'observation' is in QM. I dabble a lot in electronics and I'm painfully aware of how measurements affect a circuit - try to measure current and you introduce a voltage drop, stick a probe somewhere and you add an antenna, add capacitance, etc. So to me when trying to measure anything it seems so blatantly obvious that it has to change the outcome - you will interact in some way with the system to get any information out, and this will change the tracejctory, energy, momentum or whatever of the particles. I mean is that it? That's the mystery?
- dinkumthinkum 4y agoNo, it’s not like sticking a voltmeter on a circuit. The double slit experiment definitely does not show something obvious. If you look into it a bit more about the wave function collapse, you will see very surprising results, if you are not familiar with it. I never heard anyone say it was obvious when they learned it. :)
- changoplatanero 4y agoImagine you set up Schrodinger's cat experiment where you have a photon pass through a double slit and if it goes through the left slit then it electrocutes the cat in the box and if it goes through the right slit then the cat is spared. You set up the experiment and leave the box for two days and then come open it to "measure" if the cat is alive or dead. The mystery is that its hard to understand how performing the measurement of opening the box can change the outcome of seeing a healthy cat or one that's been dead for two days.
- SAI_Peregrinus 4y agoSchrodinger's cat thought experiment was meant to argue against the collapse-based interpretations of QM.
- DontchaKnowit 4y agoIt very obviously does not change yhe outcome here right? This is an odd example
- pdonis 4y agoThe paper goes astray in my view right at the start, when it points out that time is a parameter in the Schrodinger equation, not an operator, so that equation gives no way to uniquely derive a probability distribution for measurement results as a function of time--but then fails to note the solution to that problem, which is to not use the Schrodinger equation in the first place. The correct framework in which to treat time on the same footing as other observables is relativistic quantum field theory. That is never even mentioned in this paper. (To be fair, I have never seen any discussion or comparison of QM interpretations that uses QFT as its framework; they all use non-relativistic QM, even though we know that's just an approximation. But it's still an issue even if it's an extremely common one.)
- d_tr 4y agoI do not know QFT or String Theory and I have a question. Can these other equations be derived from the Schrödinger equation using a suitable Hamiltonian? And do you mean that you need time to be in the Hamiltonian as an observable to satisfy Lorentz invariance?
- pdonis 4y ago> Can these other equations be derived from the Schrödinger equation using a suitable Hamiltonian? No, it's the other way around: given a quantum field theory, under certain conditions (the main one I'm aware of is choosing a particular frame and taking the non-relativistic limit), you can derive a Schrodinger equation. > And do you mean that you need time to be in the Hamiltonian as an observable to satisfy Lorentz invariance? I mean that a fully relativistically correct treatment needs to treat time and space on the same footing. In quantum field theory that is usually done by making the quantum fields local operators, i.e., a quantum field is a mapping of points in spacetime to operators. In the simplest case, a free scalar field, these are the creation and annihilation operators of an infinite set of harmonic oscillators.
- prettyStandard 4y agoSean Carroll's many worlds is what I subscribe to. In a nutshell, you are a quantum system as well, when two quantum systems interact, then you get the wavefunction collapse, but it doesn't collapse, it just appears that way. https://youtu.be/F6FR08VylO4 https://youtu.be/F6FR08VylO4
- d_tr 4y agoSean Carroll is not the originator of the MWI by the way, Hugh Everett is.
- prettyStandard 4y agoYes agreed. I got lazy and didn't elaborate like I should have. I wanted to say Sean Caroll's talk on many worlds is the most coherent explanation I've seen of quantum mechanics so far.
- d_tr 4y agoI studied some QM on my own a while ago and while I could just do what the problems asked me to, I was really confused about how a quantum system is supposed to evolve assuming the state collapses. Then I got to density matrices and understood what that "parallel universes" thing actually is... It removed a major source of confusion.