91–100 of 167 posts
Highly recommend looking at Jacob Barandes’ formulation of quantum mechanics as non-Markovian stochastic processes. It was the first introduction to quantum mechanics I could actually follow. https://www.jacobbarandes.com/
Im fully willing to believe I just don’t “get it” but I took a pretty deep dive into quantum computing and the underlying mechanics and I kind of got the sense (with QC) that nobody really knows what they are talking about. I got this feeling so strongly that stopped studying the topic all together. I’m probably way off base and I’m probably missing some insights that I could get by going to school or something but t…
https://arxiv.org/pdf/1811.09062
However, it still doesn't really address the core question of when the collapse actually occurs. All it really seems to add is that the environment is an "observer" and that decoherence actually causes the collapse.
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"I think I can safely say that nobody understands quantum mechanics." --Richard Feynman You're far from alone. Quantum physics is tricky because it frequently doesn't agree with our physical intuition. Humans are used to dealing with macroscopic objects. They surround us for our whole lives. Matter behaves in surprisingly different ways at the level of single quanta. Seemingly impossible things flop out of the math a…
> Quantum physics is tricky because it frequently doesn't agree with our physical intuition. Quantum physics tricky for two separate reasons. (i) The mathematical theory (Schrödinger equation, wave function, operators, probabilities) is solid and well-defined, but may feel unintuitive, as you say. (ii) But quantum mechanics is also an incomplete theory. Even if you learn to be at peace with the unintuitive aspects of…
I'm thinking that the nature of intuition is about training your neurons to approximate stuff without needing to detour through conscious calculation.
And QM is in too high of a complexity class for this to be a thing.
Im fully willing to believe I just don’t “get it” but I took a pretty deep dive into quantum computing and the underlying mechanics and I kind of got the sense (with QC) that nobody really knows what they are talking about. I got this feeling so strongly that stopped studying the topic all together. I’m probably way off base and I’m probably missing some insights that I could get by going to school or something but t…
> I’m probably way off base and I’m probably missing some insights that I could get by going to school A school would usually teach the "shut up (about philosophy) and calculate" approach. These philosophical problems about the meaning of quantum mechanics have been with us for 100 years, and mainstream physics sees them as too hard or even intractable, and thus as waste of time.
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The question presupposes that "the experience of the color blue" is a discrete object that needs a storage location. But that's the dualist picture in disguise. On a functionalist view, blueness isn't stored; it's what certain neural activity constitutively is when you're that system observing that blue. As an aside, isn't it more weird that violet and purple look indistinguishable despite being physically so differe…
What is mysterious to me is why and how chemical reactions in a certain part of my brain create an experience of blue. Yes some chemical change happened there, but so what. These are not very unusual chemical reactions. They happen and are happening everywhere. Does all the chemical reactions going on generate an experience to some experiencer?
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Yes, except for the “asymmetrically” part. In other words, Many Worlds.
But isn’t it conceivable, because the original quantum state contains probabilities of different outcomes, that one imprint might correspond to “up” and another to “down,” [...] [Zurek’s theory] predicts that all the imprints must be identical. Does this not imply that there is an asymmetry, one half of the state gets imprinted, the other half neglected? This however also raises the question about the basis, what is…
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Random is a very interesting concept. In relation to nature we seem to use "random" as anything we can't or are currently unable to model. To call something random doesn't mean it's impossible to model, in fact all sorts of natural facts seemed random one day before being covered by a model. One very relatable example example is the motion of stars in the the night sky, which seemed random for ages, until the Coperni…
In science randomness is usually used to abstract over a large number of possible paths that result in some outcome without having to reason individually about any specific path or all such paths. It does not have to mean something inherently non-deterministic or something that can't be modelled, although it certainly is the case that if something is inherently non-deterministic then it would necessarily have to be m…
Output of of a pseudorandom generater is a good example.
> None of the leading interpretations of quantum theory are very convincing. They ask us to believe, for example, that the world we experience is fundamentally divided from the subatomic realm it’s built from. Or that there is a wild proliferation of parallel universes, or that a mysterious process causes quantumness to spontaneously collapse. Actually, the "many worlds" "interpretation", simply treats the highly suc…
The part that I have trouble wrapping around with many worlds interpretation is how I as an observer end up in one of the many bifurcations. Any links you can share that will help me with understanding that is welcome! The Stanford Encyclopedia of Philosophy ( https://plato.stanford.edu/entries/qm-manyworlds/ ) goes into this in some depth, and it seems like the right way to think about it is say that "I" in one bran…
Just a pleb here, but that does not stop me from thinking about it..
I think your consciousness is a function of the world you belong. So asking why your are in a certain world, and not in other, is like asking why you are born to your specific parents, and not to others.
So you don't end up in some fork, by a roll of dice, you are already confined to, and defined by a single branch.
So I don't think the exact "you" don't exist in another branch. But another consciousness that only differ from "you" by only a single random event (ie you and this consciousness only differ from you in the observation of a single random event) exist in another branch.
And it is not like this is all orchestrated by some entity. It is just how consciousness and subjective experiences emerges in mathematical structures (+ the set of random events), that does not need rendering anywhere (Mathematical Universe Hypothesis).
Once you understand the hopeless inevitablity of existence, a lot of questions like "When", "how", or "why" of our existence disappears.
You can ask if there is any proof for this, except for some thought experiment. But I think the only thing that can come close to proving this is if we exhaustively searched for other extra terrestrial consciousness and don't find any.
https://www.quantamagazine.org/quantum-darwinism-an-idea-to-...
I feel that it really just gives an explanation of decoherence, but doesnt offer any testable hypothesis for darwinian pruning and collapse to pointer states.
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Yes, except for the “asymmetrically” part. In other words, Many Worlds.
But isn’t it conceivable, because the original quantum state contains probabilities of different outcomes, that one imprint might correspond to “up” and another to “down,” [...] [Zurek’s theory] predicts that all the imprints must be identical. Does this not imply that there is an asymmetry, one half of the state gets imprinted, the other half neglected? This however also raises the question about the basis, what is…
Indeed, as you say, Decoherence explains why certain bases are special: when a system is in a pointer basis state, it does not continue entangling with environment (or, at least, does so minimally). When a spinning particle enters a Stern-Gerlach apparatus oriented in z-direction, spin-z is the pointer basis of the system during its time in the apparatus. A spin-up or spin-down particle does not entangle with the environment, but spin +x state would quickly entangle with environment, placing environment in a superposition and "branching" the total state vector of all the stuff in the universe.
Quantum Darwinism is just a refinement of this picture in which the "environment" interacting with the system is itself modeled a series of fragments (i.e. all the different photons that bounce off object). It turns out that the information about which pointer basis state the system is in (spin up or spin down) is redundantly encoded in each of these fragments. Hence, intercepting one photon that interacted with system and reveals "spin-up" (because the particle is in upper path) agrees with other photons that also bounce off object.
BUT, of course, due to linearity of unitary time evolution, there is another "branch" in which spin-down was the outcome of the measurement and everyone agrees on spin-down. This is exactly the Everett picture.