3 ms·

I did not say it made anything easier to understand. I did not say it made anything clearer. I did not say I like it better. Stop putting words into my mouth.

by mort96 4y ago

I did not say it made anything easier to understand. I did not say it made anything clearer. I did not say I like it better. Stop putting words into my mouth. I said it has fewer mechanism. Which it does. Because it does not have the wave function collapse mechanism.

Jensson 4y ago
But the wave function collapse is there. Wave functions stops interacting with each other, that is a micro system phenomena, it requires nothing of our macro state magic, and we can observe it, it happens, and that is what we call "wave function collapse", and it happen in MWI.
- mort96 4y ago
  In MWI, there is one single wave function. It is the single wave function which describes the state of "the multiverse". It is always in a superposition of eigenstates. It never collapses. That's literally the entire point of the MWI. If you refuse to understand that, you have some reading to do. I don't believe further discussion is fruitful.
  - Jensson 4y ago
    But that wave function still gets transformed similar ways as wave function collapses would. You can turn around a particle with wave function collapses, we have done that in reality, so no matter how you structure your MWI the wave function collapse is there. That giant waveform you are talking about thus has to react to wave function collapses, there is no way around it.
    - mort96 4y ago
      > But that wave function still gets transformed similar ways as wave function collapses would. No it doesn't? After a wave function collapse, a particle's (or quantum system's) wave function is reduced from representing a superposition of eigenstates to representing one eigenstate. That does not happen in MWI. I don't understand why you find that so difficult to accept. If a particle is in a superposition, and an observer observes the particle, MWI says that the observer also enters a superposition with one eigenstate for each of the particle eigenstates, following the normal "rules" of interaction/entanglement since the observer is also a quantum system. There is no collapse.
      - Jensson 4y ago
        > That does not happen in MWI So if I use a series of quantum collapses to move a particle a meter forward, a state it wasn't originally in, how would that work in MWI? To do that you just make a long series of "measurements", each perturbation so small that the chance is basically 100% since the chance is squared with the overlap, how did that particle get moved according to MWI? How do you explain that without wavefunction collapse?
        mort96 4y ago
        For each event you experience as a "collapse", you "branch" the wave function. You put a particle into a superposition between two eigenstates representing two positions, then you observe the particle, and as a result, you as the observer enter a superposition; you now have two eigenstates, one where you observed the particle being in the one location, and one where you observed the particle being in the other location. And since you and your measurement equipment and everything else macroscopic is highly entangled with the rest of the world, the whole world also enters the same superposition, one where the particle was in one place, and one where it was in the other. Repeat until one "branch" in the "tree" has observed the particle moving a meter.
        Jensson 4y ago
        But the particle moving a meter in this scenario isn't described by the Schrödinger equation or any other part of quantum mechanics. If you just measured the chance of it being there originally it would be 0% chance, it isn't there. The only thing moving the particle is the wave function collapse. I don't see how the theory can be both correct and ignore that the wavefunction collapse can move particles into states they weren't originally in. You would need new rules for the wave function in order for MWI to work, one that handles the collapses. But if you do that I wouldn't call the theory "just standard quantum mechanics without collapses".
        mort96 4y ago
        But you're influencing the particle between each step, right? Is my understanding correct that you put the particle in a superposition, observe it a little bit further along, then put it in another superposition, observe it further along again, etc until it has moved a meter? I don't see why you would expect there to be some probability to see the particle as having moved a whole meter after the first observation. Obviously you putting it in a superposition in between steps is an important factor. And each time you've first put it in a superposition and then observed it, you've created two branches of what we would classically call the universe. The only thing which really changes between an interpretation with collapse and an interpretation without collapse, is that in one without collapse (i.e MWI), the universal wave function splits into two "branches" which can't interact after the split. Sadly, I don't know much about the math though, so it's completely possible that I've missed some detail in your question and given a reply which doesn't address what you're getting at. If that's the case, I've probably reached my limit and you'd have to ask someone who has studied this way, way more than me.

by mort96 4y ago

Jensson 4y ago

But the wave function collapse is there. Wave functions stops interacting with each other, that is a micro system phenomena, it requires nothing of our macro state magic, and we can observe it, it happens, and that is what we call "wave function collapse", and it happen in MWI.

mort96 4y ago
In MWI, there is one single wave function. It is the single wave function which describes the state of "the multiverse". It is always in a superposition of eigenstates. It never collapses. That's literally the entire point of the MWI. If you refuse to understand that, you have some reading to do. I don't believe further discussion is fruitful.
- Jensson 4y ago
  But that wave function still gets transformed similar ways as wave function collapses would. You can turn around a particle with wave function collapses, we have done that in reality, so no matter how you structure your MWI the wave function collapse is there. That giant waveform you are talking about thus has to react to wave function collapses, there is no way around it.
  - mort96 4y ago
    > But that wave function still gets transformed similar ways as wave function collapses would. No it doesn't? After a wave function collapse, a particle's (or quantum system's) wave function is reduced from representing a superposition of eigenstates to representing one eigenstate. That does not happen in MWI. I don't understand why you find that so difficult to accept. If a particle is in a superposition, and an observer observes the particle, MWI says that the observer also enters a superposition with one eigenstate for each of the particle eigenstates, following the normal "rules" of interaction/entanglement since the observer is also a quantum system. There is no collapse.
    - Jensson 4y ago
      > That does not happen in MWI So if I use a series of quantum collapses to move a particle a meter forward, a state it wasn't originally in, how would that work in MWI? To do that you just make a long series of "measurements", each perturbation so small that the chance is basically 100% since the chance is squared with the overlap, how did that particle get moved according to MWI? How do you explain that without wavefunction collapse?
      - mort96 4y ago
        For each event you experience as a "collapse", you "branch" the wave function. You put a particle into a superposition between two eigenstates representing two positions, then you observe the particle, and as a result, you as the observer enter a superposition; you now have two eigenstates, one where you observed the particle being in the one location, and one where you observed the particle being in the other location. And since you and your measurement equipment and everything else macroscopic is highly entangled with the rest of the world, the whole world also enters the same superposition, one where the particle was in one place, and one where it was in the other. Repeat until one "branch" in the "tree" has observed the particle moving a meter.
        Jensson 4y ago
        But the particle moving a meter in this scenario isn't described by the Schrödinger equation or any other part of quantum mechanics. If you just measured the chance of it being there originally it would be 0% chance, it isn't there. The only thing moving the particle is the wave function collapse. I don't see how the theory can be both correct and ignore that the wavefunction collapse can move particles into states they weren't originally in. You would need new rules for the wave function in order for MWI to work, one that handles the collapses. But if you do that I wouldn't call the theory "just standard quantum mechanics without collapses".
        mort96 4y ago
        But you're influencing the particle between each step, right? Is my understanding correct that you put the particle in a superposition, observe it a little bit further along, then put it in another superposition, observe it further along again, etc until it has moved a meter? I don't see why you would expect there to be some probability to see the particle as having moved a whole meter after the first observation. Obviously you putting it in a superposition in between steps is an important factor. And each time you've first put it in a superposition and then observed it, you've created two branches of what we would classically call the universe. The only thing which really changes between an interpretation with collapse and an interpretation without collapse, is that in one without collapse (i.e MWI), the universal wave function splits into two "branches" which can't interact after the split. Sadly, I don't know much about the math though, so it's completely possible that I've missed some detail in your question and given a reply which doesn't address what you're getting at. If that's the case, I've probably reached my limit and you'd have to ask someone who has studied this way, way more than me.