6 ms·

My understanding is that any kind of measurement will do, it doesn't matter how you get it. You could use photons to do the measurement but there are other ways

by warent 6y ago

My understanding is that any kind of measurement will do, it doesn't matter how you get it. You could use photons to do the measurement but there are other ways which all have the same result. It's a mystery how the particle "knows" (In other words, nobody knows when the wave function collapses) but one popular interpretation is that the particle exists in all states, i.e. in a pure description of reality. When any quantum system interacts with it, then it becomes entangled with the result of that measurement, branching it into a new universe (edit for clarification: a new world where it was as if it was never a wave, and it was always a particle). That's my understanding of the many-worlds theory. That entanglement propagates across nearby particles, so it doesn't have anything to do with eyes or consciousness. If the air molecules around your body interact with the particle then that entanglement propagates through your body and places you in the new world.

tabtab 6y ago
Re: When any quantum system interacts with it, then it becomes entangled with the result of that measurement, branching it into a new universe. That's my understanding of the many-worlds theory. This is a case of a simple theory that indeed models the mystery well. However, it seems "wasteful" in that it would branch into gazillion trees of reality. In Occam's Razor, does "simplicity" include quantity of "stuff" needed? Because sometimes the brute force algorithm/model is the "simplest" if we ignore quantity of stuff and time, such as bubble-sort. Bubble-sort is one of the simplest sorting algorithms known, but is inefficient from a time and resource standpoint. If there are "free" dimensions to spare out there, then the "wasteful" multi-verse model may not really be wasteful. We humans are used to thinking in terms of economic trade-offs, and a model that uses up large quantities of space/time rubs our instincts wrong. If true, the theory means that in some universe somewhere I'm a billionaire who married a supermodel.
- tim333 6y ago
  If the universe is a mathematical object there being an infinity of universes isn't any more wasteful than there being an infinity of integers for example. From Occam's point of view it's simpler if all integers exist rather than there being a cap if that were even logically possible. So yeah go supermodel!
  - tabtab 6y ago
    Re: If the universe is a mathematical object... Math is a modeling technique, not a "thing". To me it doesn't make sense to say the universe "is" math. Maybe it's a machine "running" math notation (programming code), but that's not the same as it "being" math. (Is "God" the server admin?)
    - tim333 6y ago
      It's been hypothesised: "the physical universe is not merely described by mathematics, but is mathematics" https://en.wikipedia.org/wiki/Mathematical_universe_hypothesis https://en.wikipedia.org/wiki/Mathematical_universe_hypothes... not proven of course.
    - handol 6y ago
      Suppose God is running multiple identical instances of the universe on several machines. Are we in a particular one?
      - tabtab 6y ago
        We wouldn't know or care and it would make no difference. It only becomes an "issue" if there is a mutation or glitch that breaks symmetry.
  - Waterfall 6y ago
    The universe isn't mathematical, it is explained by math, a country is not Chinese because I wrote a tour guide in Chinese about it. Infinite universes isn't really applicable here, you're thinking of a growing block universe. A simpler point is a block universe. https://en.m.wikipedia.org/wiki/Eternalism_(philosophy_of_time) https://en.m.wikipedia.org/wiki/Eternalism_(philosophy_of_ti...
    - Koshkin 6y ago
      But if Chinese was the only language (which is a more correct analogy), the country might in fact be Chinese.
- deleted 6y ago
  [deleted]
- RobertoG 6y ago
  >>"However, it seems "wasteful" in that it would branch into gazillion trees of reality." In a way, it could be interpreted as very efficient. Only the branches where some "measurement" is done are "calculated". I suppose the others are garbage collected at the end of time, or something like that. And maybe it's not a tree, but a graph of universes. In the same way that a universe split in two, two universe could also fuse into one when they share the previous state. Somehow it feels like this have to be connected to reversible vs. non-reversible computation. Ah.. it's a good feeling being a fearless dilettante.
  - tabtab 6y ago
    Re: Only the branches where some "measurement" is done are "calculated". I suppose the others are garbage collected at the end of time, or something like that. But that's adding complexity back into it. You are increasing complexity of the theory/model by adding a complex cleaner/trimmer in order to reduce the quantity of resources consumed.
- deleted 6y ago
  [deleted]
- warent 6y ago
  I think you're mixing up metaphysics and human intuition with what the math describes. The current math says there may be essentially infinite worlds created in infinite time, where yes there is least one in which you are a billionaire married to a supermodel. The only constraint is in the properties of nature (e.g. a world will never be created in which an electron has 0 spin). However, I agree with you that it seems implausible because it implies absurd situations like, there is a world in which someone lives a life of celebrity because every time they roll some dice it always lands on 6, and every time they flip a coin it lands on heads, etc.
- tsimionescu 6y ago
  Even worse, many-worlds doesn't really solve the problem anyway - it still doesn't explain WHY you only observe one result, when the Schrodinger equation predicts several. That is, why can't you see the other worlds?
  - warent 6y ago
    That doesn't seem like a question that can be answered mathematically, does it? That's like asking, why do electrons have a spin of 1/2? Why is the speed of light 299,792,458 m/s? These are just properties of the universe.
    - tsimionescu 6y ago
      Not really. It's the same question as the measurement problem: Schrodinger's equation predicts that a particle can exist in many places at the same time, with different amplitudes, and interact with particles in all those places. However, if we want to predict the particle's movement after it encounters a detector, we need to update the wave function to set its probability to 1 at the position of the detector and 0 everywhere else - otherwise, our predictions are measurably wrong. Now, the question is: what causes this discontinuity in the equations of motion? Why is interaction with a detector different than interaction with another particle? Many Worlds simply reframes this problem, but doesn't get rid of it. In MWI, you would say 'the particle moves in all universes according to the wave function, until it interacts with a detector, possibly interfering with versions of itself in other universes. Then, when it encounters the detector, the world line of the detector splits - in some universes it passes the detector, in others it doesn't. However, it no longer interacts with other versions of itself,so we must update the wave function inside the universe where it passed the detector'.
      - warent 6y ago
        > Now, the question is: what causes this discontinuity in the equations of motion? Why is interaction with a detector different than interaction with another particle? > Many Worlds simply reframes this problem, but doesn't get rid of it. Maybe I'm misunderstanding. It's like asking "why is there a difference between me jumping in a swimming pool and someone else jumping in it? I don't get wet when someone else is swimming." The difference is... one of you is in the pool. It's not going to spontaneously make the other person wet. In MWI the difference is that if it interacts with a particle, you're not entangled, the particle is. If it interacts with a detector then you're entangled. So, there is no difference except for what gets entangled. What that means is the wave function can only appear to collapse when you entangle. If some particle entangles, it will collapse for that particle and branch into a new world, but you're not in that world; for you it's still a waveform. Edited for clarity.
Waterfall 6y ago
Ever heard of pilot wave theory? https://en.m.wikipedia.org/wiki/De_Broglie%E2%80%93Bohm_theory https://en.m.wikipedia.org/wiki/De_Broglie%E2%80%93Bohm_theo... It's an easy visualization that can be shown with speakers and liquid
- tabtab 6y ago
  But to fit experimental observations, the "wave" would have to be faster than light.
  - jsmith45 6y ago
    Yeah. On the other hand it does give decent intuition about how certain interactions would result, especially if talking about massive particles traveling much slower than light. I remember reading an article here a while back that involved a macroscopic re-creation of the double slit experiment results, but where mere observation remained possible, because light did not sufficiently influence the substrate. In that experiment the particles were droplets traveling on top of a set of waves, working in the pilot wave fashion. Any attempt to use anything of similar scale to the particles to observe which slit the drop went through would break the interference pattern, but mere light did not, allowing one to visually see how a pilot wave style interpretation could work, if it were not for that whole (photons travel at the speed of light, so these would need to be faster than light propagating pilot waves) thing. Indeed it looks like flubert linked a video from an earlier study of the same basic mechanics, prior to the more recent one that included the double slit experiment replication.
    - flubert 6y ago
      I was under the impression that the double slit experiment with the oil drops does not replicate the quantum mechanics expected interference pattern. http://math.mit.edu/~bush/wordpress/wp-content/uploads/2017/12/Pucci-Slits-2017.pdf http://math.mit.edu/~bush/wordpress/wp-content/uploads/2017/...
- flubert 6y ago
  Here's one interesting silicone oil pilot-wave video: https://www.youtube.com/watch?v=nmC0ygr08tE https://www.youtube.com/watch?v=nmC0ygr08tE
thaumasiotes 6y ago
> one popular interpretation is that the particle exists in all states, i.e. in a pure description of reality. When any quantum system interacts with it, then it becomes entangled with the result of that measurement, branching it into a new universe (edit for clarification: a new world where it was as if it was never a wave, and it was always a particle). The two-slit experiment contradicts this. You get different results depending on when you perform the observation(s). So the new world is a world where the particle was originally a wave, and became a particle when it was observed. Not a world where the particle was always a particle.

by warent 6y ago

tabtab 6y ago

Re: When any quantum system interacts with it, then it becomes entangled with the result of that measurement, branching it into a new universe. That's my understanding of the many-worlds theory. This is a case of a simple theory that indeed models the mystery well. However, it seems "wasteful" in that it would branch into gazillion trees of reality. In Occam's Razor, does "simplicity" include quantity of "stuff" needed? Because sometimes the brute force algorithm/model is the "simplest" if we ignore quantity of stuff and time, such as bubble-sort. Bubble-sort is one of the simplest sorting algorithms known, but is inefficient from a time and resource standpoint. If there are "free" dimensions to spare out there, then the "wasteful" multi-verse model may not really be wasteful. We humans are used to thinking in terms of economic trade-offs, and a model that uses up large quantities of space/time rubs our instincts wrong. If true, the theory means that in some universe somewhere I'm a billionaire who married a supermodel.

tim333 6y ago
If the universe is a mathematical object there being an infinity of universes isn't any more wasteful than there being an infinity of integers for example. From Occam's point of view it's simpler if all integers exist rather than there being a cap if that were even logically possible. So yeah go supermodel!
- tabtab 6y ago
  Re: If the universe is a mathematical object... Math is a modeling technique, not a "thing". To me it doesn't make sense to say the universe "is" math. Maybe it's a machine "running" math notation (programming code), but that's not the same as it "being" math. (Is "God" the server admin?)
  - tim333 6y ago
    It's been hypothesised: "the physical universe is not merely described by mathematics, but is mathematics" https://en.wikipedia.org/wiki/Mathematical_universe_hypothesis https://en.wikipedia.org/wiki/Mathematical_universe_hypothes... not proven of course.
  - handol 6y ago
    Suppose God is running multiple identical instances of the universe on several machines. Are we in a particular one?
    - tabtab 6y ago
      We wouldn't know or care and it would make no difference. It only becomes an "issue" if there is a mutation or glitch that breaks symmetry.
- Waterfall 6y ago
  The universe isn't mathematical, it is explained by math, a country is not Chinese because I wrote a tour guide in Chinese about it. Infinite universes isn't really applicable here, you're thinking of a growing block universe. A simpler point is a block universe. https://en.m.wikipedia.org/wiki/Eternalism_(philosophy_of_time) https://en.m.wikipedia.org/wiki/Eternalism_(philosophy_of_ti...
  - Koshkin 6y ago
    But if Chinese was the only language (which is a more correct analogy), the country might in fact be Chinese.
deleted 6y ago
[deleted]
RobertoG 6y ago
>>"However, it seems "wasteful" in that it would branch into gazillion trees of reality." In a way, it could be interpreted as very efficient. Only the branches where some "measurement" is done are "calculated". I suppose the others are garbage collected at the end of time, or something like that. And maybe it's not a tree, but a graph of universes. In the same way that a universe split in two, two universe could also fuse into one when they share the previous state. Somehow it feels like this have to be connected to reversible vs. non-reversible computation. Ah.. it's a good feeling being a fearless dilettante.
- tabtab 6y ago
  Re: Only the branches where some "measurement" is done are "calculated". I suppose the others are garbage collected at the end of time, or something like that. But that's adding complexity back into it. You are increasing complexity of the theory/model by adding a complex cleaner/trimmer in order to reduce the quantity of resources consumed.
deleted 6y ago
[deleted]
warent 6y ago
I think you're mixing up metaphysics and human intuition with what the math describes. The current math says there may be essentially infinite worlds created in infinite time, where yes there is least one in which you are a billionaire married to a supermodel. The only constraint is in the properties of nature (e.g. a world will never be created in which an electron has 0 spin). However, I agree with you that it seems implausible because it implies absurd situations like, there is a world in which someone lives a life of celebrity because every time they roll some dice it always lands on 6, and every time they flip a coin it lands on heads, etc.
tsimionescu 6y ago
Even worse, many-worlds doesn't really solve the problem anyway - it still doesn't explain WHY you only observe one result, when the Schrodinger equation predicts several. That is, why can't you see the other worlds?
- warent 6y ago
  That doesn't seem like a question that can be answered mathematically, does it? That's like asking, why do electrons have a spin of 1/2? Why is the speed of light 299,792,458 m/s? These are just properties of the universe.
  - tsimionescu 6y ago
    Not really. It's the same question as the measurement problem: Schrodinger's equation predicts that a particle can exist in many places at the same time, with different amplitudes, and interact with particles in all those places. However, if we want to predict the particle's movement after it encounters a detector, we need to update the wave function to set its probability to 1 at the position of the detector and 0 everywhere else - otherwise, our predictions are measurably wrong. Now, the question is: what causes this discontinuity in the equations of motion? Why is interaction with a detector different than interaction with another particle? Many Worlds simply reframes this problem, but doesn't get rid of it. In MWI, you would say 'the particle moves in all universes according to the wave function, until it interacts with a detector, possibly interfering with versions of itself in other universes. Then, when it encounters the detector, the world line of the detector splits - in some universes it passes the detector, in others it doesn't. However, it no longer interacts with other versions of itself,so we must update the wave function inside the universe where it passed the detector'.
    - warent 6y ago
      > Now, the question is: what causes this discontinuity in the equations of motion? Why is interaction with a detector different than interaction with another particle? > Many Worlds simply reframes this problem, but doesn't get rid of it. Maybe I'm misunderstanding. It's like asking "why is there a difference between me jumping in a swimming pool and someone else jumping in it? I don't get wet when someone else is swimming." The difference is... one of you is in the pool. It's not going to spontaneously make the other person wet. In MWI the difference is that if it interacts with a particle, you're not entangled, the particle is. If it interacts with a detector then you're entangled. So, there is no difference except for what gets entangled. What that means is the wave function can only appear to collapse when you entangle. If some particle entangles, it will collapse for that particle and branch into a new world, but you're not in that world; for you it's still a waveform. Edited for clarity.

Waterfall 6y ago

Ever heard of pilot wave theory? https://en.m.wikipedia.org/wiki/De_Broglie%E2%80%93Bohm_theory https://en.m.wikipedia.org/wiki/De_Broglie%E2%80%93Bohm_theo... It's an easy visualization that can be shown with speakers and liquid

tabtab 6y ago
But to fit experimental observations, the "wave" would have to be faster than light.
- jsmith45 6y ago
  Yeah. On the other hand it does give decent intuition about how certain interactions would result, especially if talking about massive particles traveling much slower than light. I remember reading an article here a while back that involved a macroscopic re-creation of the double slit experiment results, but where mere observation remained possible, because light did not sufficiently influence the substrate. In that experiment the particles were droplets traveling on top of a set of waves, working in the pilot wave fashion. Any attempt to use anything of similar scale to the particles to observe which slit the drop went through would break the interference pattern, but mere light did not, allowing one to visually see how a pilot wave style interpretation could work, if it were not for that whole (photons travel at the speed of light, so these would need to be faster than light propagating pilot waves) thing. Indeed it looks like flubert linked a video from an earlier study of the same basic mechanics, prior to the more recent one that included the double slit experiment replication.
  - flubert 6y ago
    I was under the impression that the double slit experiment with the oil drops does not replicate the quantum mechanics expected interference pattern. http://math.mit.edu/~bush/wordpress/wp-content/uploads/2017/12/Pucci-Slits-2017.pdf http://math.mit.edu/~bush/wordpress/wp-content/uploads/2017/...
flubert 6y ago
Here's one interesting silicone oil pilot-wave video: https://www.youtube.com/watch?v=nmC0ygr08tE https://www.youtube.com/watch?v=nmC0ygr08tE

thaumasiotes 6y ago

> one popular interpretation is that the particle exists in all states, i.e. in a pure description of reality. When any quantum system interacts with it, then it becomes entangled with the result of that measurement, branching it into a new universe (edit for clarification: a new world where it was as if it was never a wave, and it was always a particle). The two-slit experiment contradicts this. You get different results depending on when you perform the observation(s). So the new world is a world where the particle was originally a wave, and became a particle when it was observed. Not a world where the particle was always a particle.