This talk was held during the "Summer School on the Foundations of Quantum Mechanics dedicated to John Bell" in Sesto, Italy (28.07.2014 - 30.07.2014). More information can be found on the conference website www.sexten-cfa....
This is a great talk, but I found the dot points in the presentation frustratingly unreadable. Luckily there is a PDF available to help you follow the flow of the talk. www.mathematik.uni-muenchen.de/~bohmmech/BohmHome/files/Maudlin_Sesto_2014.pdf
The issue with superdeterminism is that it can never be experimentally verified (by definition). Therefore it is viewed by many (myself included) as a more of a “cop out” than a legitimate scientific theory.
Any computer simulation of quantum mechanics needs to make use of a random number generator (stating the obvious?) but modification of the Schroedinger equation is prohibited, whether the modification be explicit or implicit. Does this bring our enquiries to a quick end? No, because there is a nonlocal degree of freedom to be exploited, as hinted at by Bell's Theorem. I propose tachyonic Brownian motion which is orthogonal to the Schroedinger equation, which is an oscillation in the other way to travel faster than light. I am sure that there are other ideas. Please let's hear them. Surely somebody like me, an amateur, doesn't have this subject all to himself ! I’m an amateur now, but I did a PhD on the computer simulation of the Navier-Stokes equations using Alexandre Chorin’s model of vorticity in Brownian motion. This requires a random number generator and it is pretty obvious to ask questions about doing something similar for quantum mechanics. One difference is that there is no viscosity term that can be added to the Schroedinger equation. We need to think of something new.
The problem here is too many words not enough equations. Talk about the equations not what other ppl say about equations you're not currently looking at. The primary issue here is that when talking about equations the ALL of the details are very important.
@simonfarre4907 guys on the quantum gift circuit (not this guy) love to talk about what the great physicists thought about the theory as it was emerging. This is a good thing for many reasons. However, what it isn't good at is building your intuition and understanding of quantum mechanics or quantum theories in general. Most physicists understand quantum mechanics far better than Feynman ever did. Why? They spent their formative years being trained by 3rd generation texts with well designed pedagogy. He didn't get to be a 20 year old with the quantum and relativistic world laid out before him with 8 digits of precision and next to zero experimental wiggle room remaining on the realism question and a well constructed proof of Born's rule by the guy who proved the no cloning theorem that has the side effect of making random probability of outcomes a fundamental property of the theory. This proof requires fewer assumptions than are generally presented in most of the accepted formulations of quantum theory but contains something of a minimal intersection of their axioms. 1. Hilbert space (ie superposition) 2. Operators are unitary 3. Measurements Repeated on very short timescales will agree (ie some version of a weak conservation law applies to measurements of a quantum state capable of holding or propagating information). So we're not really wrestling with these questions regarding fundamental structural uncertainty in the theory. Really big questions still exist but these aren't them. They were big questions that got groundbreaking answers verified by incredibly elegant and difficult experiments. But to talk about this stuff and where we think we've figured it out and where there's still enough wiggle room to drive a truck through we need equations numbers and the sketch of an experiment and it's required precision to discriminate between various competing ideas. It's science that's how we do physics you predict and you measure. Until you do this we're not able to have a meaningful exchange. So shut up and calculate... because we need something concrete to talk about... alternatively feel free to head towards the lab and make some measurements (but fyi building a scientific apparatus usually requires a lot more and more detailed calculations than just making a rough theoretical prediction).
also it turns out Gleason did the proof years before Zurek later refined it (Zurek is the guy that proved the no cloning theorem). The issue here is that no one but Zurek read Gleason's proof... and having read it myself it's not easy to follow. Regardless these results prove that Hilbert + Unitarity + weak information conservation = God playing dice ... this goes beyond Bell which makes the question implicit. Zurek's proof shows that randomness is just a side effect of the underlying geometry of pure states in these kinds of spaces. This doesn't say anything about local or realism but it removes anything deterministic from quantum theory that incorporates those assumptions. Some people say ah but strong conservation and super determinism fix the problems here... they don't, weak or strong its a MATHEMATICAL contradiction if your theory also includes Hilbert and Unitarity. To kick out randomness or use an argument/interpretation that is inconsistent with randomness you must explicitly violate weak and strong information conservation, Hilbert, or Unitarity which are all consistent with experiment. To change this requires a new experimental observation because the math we use to describe existing experiment is internally consistent. Alternatively, you need to find a mathematical system that breaks the above assumptions but still gets results that match all the experimental data.
love for Maudlin. Because he pushed the Hammer on the nail. However the world seems non local entangled as a system, if we live in one of the dual CPT symmetric copy multiverses , which are full symmetric. Called the 12x Raspberry multiverse of Q.FFF theory. Non local EPR RELATED.
I feel so non-local when I listen to Bell clarifications.. I find I get some great non local effects in my photography when I use three polarizing filters. Why are quantum physicists such horrible photographers? You need to know how to manipulate the photons or you will wash out as a photographer.
24:41 - So what the paper argues is that if you have events A and B, A cannot be thought of as disturbing or influencing B if B is outside of A's future light cone.
this is an excellent talk. best short explanation of Bell and to the actual problems concerning causality and locality confronting quantum theory. talks like this make me think more bachelors degrees should simply be replaced with philosophy/history of science.
Is it POSSIBLE to measure a quantum system without DISTURBING it? If it is impossible, then EPR is wrong because EPR posits an impossibility, thus making EPR irrelevant. Sanjosemike
15:30. EPR refer to disturbing system B when A is measured AND disturbed! Bohr reply: there are NOT two systems, is ONLY ONE, though both parts are space-like separated
There is a way around Bell's theorem, and it's superdeterminism. If one assumes that experimentalists are not free to choose the measurement they make, Bell's inequalities don't apply anymore.
That would be the conspiracy that Schrödinger was talking about (@around 38mins in the talk) Namely that not all students know all answers, but that each knows only some, and by seperate trick without realising we always pick the correct pair of student and question, and therefore without cause assume that all know all.
@@theholk I understand, but I don't think that is a correct way to see superdeterminism. In my opinion there is nothing crazy about superdeterminism, I think it is as "bad" of an interpretation as any possible other interpretation
@@jordifolch7833 Does not superdeterminism imply that our reality is actually simulated ? It's as if each particle was a "pixel" programmed in advance so that they follow specific results. If all particles are not following physical laws but just *pretend* to do it because of a program, that's pretty much the definition of a simulation.
@@En_theo Not sure I can agree totally with that. I mean, clearly everything follows the laws of physics, there is no such thing as being "out" of the laws of physics. Everything has an explanation, even if we don't know it yet (this the assumption sciene makes, things have explanation, thus phenomena follows rules/laws). I hope you agree with this. Furthermore, I wouldn't say that things that follow laws "pretend" to follow them. They simply do follow the laws of physics, I don't see a direct jump to say they pretend to do what they do, they just do it because we observe it. It is very very important, in my opinion, to keep in mind that the first assumption physics makes is that phenomena has an explanation, and that we can find such an explanation. Of course the explanations come in the form of laws, which are nothing else than patterns. So, well, everything follows laws, thus is a simulation? Not trivial and not clear to me. My only possible answer as a good scientist is that maybes yes, maybe not, I have no way to prove it or disprove it.
Maudlin doesn't provide sufficient evidence that Einstein wasn't bothered by indeterminism. As the quote clearly states, he cannot believe that God doesn't play dice AND uses 'telepathic' methods. And the reinterpretation of the analogy of a dice playing God as a criticism of nonlocality instead of indeterminism doesn't go very well.
What's manifestly local is time-keeping. Clocks do not tick at the same rate everywhere and everywhen in the cosmos. In particular, time-keeping is a function of the local gravitational field strength (and there are gravitational gradients pretty much everywhere). So what does that mean? It means that Bell's derivation is fine if you assume the hidden variable is not time-varying. But if you allow that a hidden variable is time-varying, then Bell's derivation runs into a snag where the hidden variable would otherwise vanish. Rather than vanishing, there would arise a non-vanishing "beat frequency" term that survives to the bottom line of Bell's derivation. And that's why Bell's Inequality does not apply to our cosmos, where time-keeping is local, and varies from one location to the next, due to the presence of gravitational gradients. Or, to put it another way, the hidden variable is _time_ itself. So it's not a question of "spooky action at a distance" but not-so-spooky time-keeping at a distance.
As far as I can see Bell's argument does not limit itself to time-constant hidden variables. ANY predetermined variables are ruled out, also time-varying ones. The only thing that matters in the argument, is what the value of that hidden variable is at the moment of measurement. Besides that, time only differs between two locations if these two locations are in different reference frames. If you make sure the two locations are stationary wrt. each other, and at the same gravitational potential, then there would not be any difference in time between them.
@@renedekker9806 ~ Time-varying state variables are not ruled out, but their initial state does not determine their final state, because timekeeping varies along any path where gravitational gradients are present. See, for example, the gravitational red shift of photons ascending out of the sun's photosphere. That is, time itself is the crucial "hidden variable" because the age of a particle at position x differs from the reference clock located at x=0. Were one in possession of a gravitational map along the path, one could employ a gravitational path integral to compute the state of the time-varying particle at the destination. Bell adopted the tacit simplifying assumption of no gravitational gradients which is why his prediction departs from observational measurements.
@@BarryKort _"their initial state does not determine their final state"_ - and that is fine. The hidden variables can vary all they like on the way to the detectors, and they can vary as fast or as slow as they like. Because what is measured is only that final state. It does not matter for the result of Bell's experiment what happens before that final state. It is that final state that needs to be correlated between two entangled particles. And without non-local interaction, those final states will never violate Bell's inequality, no matter how they came about. _"Bell adopted the tacit simplifying assumption of no gravitational gradients"_ - Bell made clear that any local influence on the way (including gravitational gradients), do not influence the results. And again: In experiments, Bell's inequality is violated even with no gravitational differences between the paths of the two particles. So also experimentally, it is shown that gravitational differences cannot be the reason for the violation.
@@renedekker9806 ~ Bell's Inequality is violated in every real experiment undertaken to test it. I'll repeat that: Bell's Inequality is violated. That means Bell's Inequality is an incorrect prediction, arising from an incorrect model. What mistake did Bell make in the framework that he adopted? He neglected to account for the real phenomenon that timekeeping is local. That's why his simplistic hypothesis leads to an incorrect prediction. Given that his prediction is incorrect, it means he was working from an incorrect model. I'll repeat that: Bell was working from an incorrect model. That's why he derived an incorrect prediction.
@@En_theoit is possible that we are. The reason why we don't assume it is that it isn't really very helpful. But I do agree that many things can be better understood by being part of a simulated world.
@@PhilAtremo Non-locality and entanglement is the basis of explaining the universe as a quantum computing function, although the algorithm is not yet known. As we learn more we will know how error-correction, fine tuning etc., get simulated. It will enable us to understand QM more completely,e.g. how randomness and chance are eliminated to produce life and consciousness, with perfection and with probability one.
The two entangled particles don’t care about sub-light speed observations. From their perspective, there is no such thing as distance nor time. These are constructs which only exist in our slower perspective. We see two “entangled” particles. From their perspective, they never separated but are still the same particle. We only perceive these interpretations as shadows of what’s happening.
I've also been told when discussing pilot waves that Bell ruled out hidden variables. I learned then that Bell's result involves non-locality instead. I'm still uncomfortable with non-locality. What sort of connection between entangled particles could account for it? Is that question faulty? Has non-locality really been confirmed experimentally?
_"Has non-locality really been confirmed experimentally?"_ - yes. That is what Alain Aspect, John F. Clauser and Anton Zeilinger got the 2022 Nobel Prize for.
« Entanglement » is ill named. There is nothing « entangled ». Precisely the OPPOSIT. What is observed is a NON LOCAL QUANTUM, and not two « entangled » quanta. There is only ONE single Schrödinger equation of a TENSOR PRODUCT WAVE FUNCTION describing this NON LOCAL QUANTUM. One single Schrödinger equation that CANOT be splited in two Schrödinger equations for « each part of an entangled pair of quanta ». There is no « pair ». Noting is « entangled ». There is just a NON LOCAL QUANTUM. That’s all
The distance between the experiments does not add anything. The entanglement is a fact at the departure and does not alter with travelling to the point of detection. There is a spooky action from the outset. Distance does not add anything. It is introduced to isolate the experiments, but once you have concluded that spookyness remains, you can get rid of the distance. It is only introduced for isolation purposes and confuses us to think something has to travel physically. If anything travels, it is the particle, and the uncertainty travels with it. The uncertainty is not a physical thing it is a distribution of possible outcomes. If you alter the distribution correlated particles by adding certainty, it will correlate with observation of another site. The correlation is already present at the source of entanglement.
I would appreciate seeing some evidence of preparation for this talk so that we can avoid all the ums and ahs that he started with. I’m not staying to watch
Complete tripe. He spent an hour dancing around a subject, that those who are interested, would be familiar with. He did NOT explain "What Bell did". I could have given his talk, and I'm just a humble retired Electrical Engineer. Its what I've always thought - academic's are mostly full of BS and get their money for nothing.
Why does anyone assume that these states have to be predetermined? Reflexive processing is the logical option, one which restores meaning to causality and eliminates the infinite regress of prior causes.
Perhaps the two best examples are the "double slit" and "quantum Zeno" experiments. When changes are made to these experiments, the observable properties of the quantum system changes reflexively. For example it's generally impossible to determine the trajectory of a single photon relative to two slits, or determine which particle will decay next with a given radioactive element. However, when specific experimental conditions prevail, it then becomes possible to determine these properties. The change of properties is reflexive each and every time the experiment "makes it possible" to determine these properties (essentially location & trajectory), whereas it's not possible *whatsoever* (in principle) to determine them w/o the experiment. In lieu of the experiment, the "properties" in question are observed to be "random", ie "wave patterns" or else "radioactive decay". Upon initiation of the experimental procedure, the properties change, and do so reflexively, into "stable" and "predictable" patterns, ie "particle patterns" and "non radioactive elements.
@@xxxYYZxxx As I understand it, reflexive processing involves becoming aware of your biases and how they affect the interpretation of empirical findings. The trouble for this argument is that you cannot eliminate the impact of your own ‘cultural baggage’ by suggesting that the other party might not be aware of their own. (Which with regard to Tim Maudlin appears to miss his point.) And there is a second problem. Your argument boils down to a tautology: It is because it is observable, and it is observable because it is.
@@TedsBeach Reflexive processing is both Ontological and Epistemological in nature. Perception is reflexive as are the physical and metaphysical processes which underlie it. The reflexive nature of perception is exhibited by its biconditional relation to binary logic. I haven't watched the video in years, so your comments about "cultural baggage" elude my grasp, however a tautological argument isn't a "problem", rather it's one which can't be logically refuted, so I thank you for the praise.
