4 ms·

Entanglement is not a non-local interaction, it means that state of the system can not be separated into independent states of its constituents. That altering t

Entanglement is not a non-local interaction, it means that state of the system can not be separated into independent states of its constituents. That altering the state of one particle could non-locally influence the state of another particle far away is not really a mind-bending idea, pressing the power button on a remote control turning on the TV across the room is pretty much the same thing, at least to our human perception as we can not see the IR light and the speed of light is essentially infinite on a human scale. But that is not how to think about entanglement properly, that is much more mind-bending. The remote control and the TV become a unit and only this unit has a state, neither the TV nor the remote control have an independent state of their own. Note that entanglement requires superposition, without it you can separate the state. The state power button not pressed and TV on can obviously be separated into independent states for both devices, but power button not pressed and TV off or power button pressed and TV on can not. You could try to say the power button is pressed or not pressed and the TV is on or off, but that description would not account for the correlation that power button pressed implies TV off (and vice versa) and power button not pressed implies TV on (and vice versa).

bowsamic 3y ago
> Entanglement is not a non-local interaction, it means that state of the system can not be separated into independent states of its constituents. Yes, and then what happens when you decide to measure the state of the part of the system that lies in one region of space? > That altering the state of one particle could non-locally influence the state of another particle far away is not really a mind-bending idea, pressing the power button on a remote control turning on the TV across the room is pretty much the same thing, at least to our human perception as we can not see the IR light and the speed of light is essentially infinite on a human scale. That's irrelevant, because EM is local in physics.
- danbruc 3y ago
  Yes, and then what happens when you decide to measure the state of the part of the system that lies in one region of space? If I had any good idea, I would go pick up my Nobel Prize. The only thing I can really say is that I do not think that the wave function instantly collapses as this would be a non-unitarity evolution of the wave function. That's irrelevant, because EM is local in physics. You missed my point, I of course did not want to say that turning on the TV is a non-local interaction, just that it looks like one to humans. So if non-local interaction was all that is going on in quantum mechanics, than it would not be that hard to make sense of it, as we have an intuition for non-local interactions, even though only from things that look like non-local interactions to us but are not actually non-local interactions.
  - bowsamic 3y ago
    > If I had any good idea, I would go pick up my Nobel Prize. Well, we already have many ideas, as summarised by the various interpretations of quantum mechanics, some of which have instantaneous non-local interaction. > The only thing I can really say is that I do not think that the wave function instantly collapses as this would be a non-unitarity evolution of the wave function. Sure, but many people do think it does, and such an interpretation is totally compatible with QM. > You missed my point, I of course did not want to say that turning on the TV is a non-local interaction, just that it looks like one to humans. So if non-local interaction was all that is going on in quantum mechanics, than it would not be that hard to make sense of it, as we have an intuition for non-local interactions, even though only from things that look like non-local interactions to us but are not actually non-local interactions. But it's irrelevant because physics isn't about what things "seem like to humans", it's about what we actually measure and how to create theories that explain and predict it.
    - danbruc 3y ago
      Sure, but many people do think it does, and such an interpretation is totally compatible with QM. The Schrödinger equation and wave function collapse are not compatible. Maybe they could be integrated in some theory, but that will need a lot of additional explaining when and how the evolution changes between being unitary and non-unitary. But it's irrelevant because physics isn't about what things "seem like to humans", it's about what we actually measure and how to create theories that explain and predict it. You are still missing my point. Quantum mechanics in general and entanglement in particular are arguably hard to understand because they are unintuitive. If all that was going on were some non-local interactions, than entanglement would not be hard to understand because non-local interactions are intuitive to us because we are familiar with things that look like non-local interactions to us. Now turn this argument around. We are still having a lot of trouble making sense of quantum mechanics, therefore it seems unlikely that non-locality is at the core of quantum mechanics, because if it was and would explain everything, than it would not be so difficult to grasp quantum mechanics because we have an intuition for non-local behavior. This is obviously no rigoros argument but it was also never was meant to be one.

bowsamic 3y ago

> Entanglement is not a non-local interaction, it means that state of the system can not be separated into independent states of its constituents. Yes, and then what happens when you decide to measure the state of the part of the system that lies in one region of space? > That altering the state of one particle could non-locally influence the state of another particle far away is not really a mind-bending idea, pressing the power button on a remote control turning on the TV across the room is pretty much the same thing, at least to our human perception as we can not see the IR light and the speed of light is essentially infinite on a human scale. That's irrelevant, because EM is local in physics.

danbruc 3y ago
Yes, and then what happens when you decide to measure the state of the part of the system that lies in one region of space? If I had any good idea, I would go pick up my Nobel Prize. The only thing I can really say is that I do not think that the wave function instantly collapses as this would be a non-unitarity evolution of the wave function. That's irrelevant, because EM is local in physics. You missed my point, I of course did not want to say that turning on the TV is a non-local interaction, just that it looks like one to humans. So if non-local interaction was all that is going on in quantum mechanics, than it would not be that hard to make sense of it, as we have an intuition for non-local interactions, even though only from things that look like non-local interactions to us but are not actually non-local interactions.
- bowsamic 3y ago
  > If I had any good idea, I would go pick up my Nobel Prize. Well, we already have many ideas, as summarised by the various interpretations of quantum mechanics, some of which have instantaneous non-local interaction. > The only thing I can really say is that I do not think that the wave function instantly collapses as this would be a non-unitarity evolution of the wave function. Sure, but many people do think it does, and such an interpretation is totally compatible with QM. > You missed my point, I of course did not want to say that turning on the TV is a non-local interaction, just that it looks like one to humans. So if non-local interaction was all that is going on in quantum mechanics, than it would not be that hard to make sense of it, as we have an intuition for non-local interactions, even though only from things that look like non-local interactions to us but are not actually non-local interactions. But it's irrelevant because physics isn't about what things "seem like to humans", it's about what we actually measure and how to create theories that explain and predict it.
  - danbruc 3y ago
    Sure, but many people do think it does, and such an interpretation is totally compatible with QM. The Schrödinger equation and wave function collapse are not compatible. Maybe they could be integrated in some theory, but that will need a lot of additional explaining when and how the evolution changes between being unitary and non-unitary. But it's irrelevant because physics isn't about what things "seem like to humans", it's about what we actually measure and how to create theories that explain and predict it. You are still missing my point. Quantum mechanics in general and entanglement in particular are arguably hard to understand because they are unintuitive. If all that was going on were some non-local interactions, than entanglement would not be hard to understand because non-local interactions are intuitive to us because we are familiar with things that look like non-local interactions to us. Now turn this argument around. We are still having a lot of trouble making sense of quantum mechanics, therefore it seems unlikely that non-locality is at the core of quantum mechanics, because if it was and would explain everything, than it would not be so difficult to grasp quantum mechanics because we have an intuition for non-local behavior. This is obviously no rigoros argument but it was also never was meant to be one.