5 ms·

I mean, your argument supposes that the system can't have that many bits -- but doesn't your device to generate arbitrary bits require more bits to be generated

I mean, your argument supposes that the system can't have that many bits -- but doesn't your device to generate arbitrary bits require more bits to be generated than that amount? Your argument sounds like "5 bits is too many bits to have in a system, and my 10 bit device can generate 5 bits!" I guess? But that doesn't really seem interesting to me: impossible outcomes from impossible to construct situations don't matter. Also, any value which can take on an arbitrary real (or even rational) number has arbitrary storage capcity -- and so far as I know, lots of quantum values do.

lisper 10y ago
Did you not bother to read the original article? "Now an international collaboration led by Adán Cabello has invoked a fundamental thermodynamics result, the Landauer erasure principle, to show that systems in hidden-variable theories must have an infinite memory to be compatible with quantum mechanics." All I'm saying is that you don't need thermodynamics to show this. Conservation laws are enough.
- SomeStupidPoint 10y ago
  My point was your argument doesn't hold, because you cant actually construct a situation in which the system doesnt already have sufficient storage capacity: the inability to require those bits without already having enough bits in the system to store them is pretty important. I don't believe that it can require QM to account for arbitrary memory, without presupposing we have it to construct the device. Hence, impossible constructions dont matter. I have some similar objections to the summary of their paper, but I haven't had time to read it yet. It's possible they address some of them. In particular, measuring from an arbitrary location and an arbitrary number of times sounds like the introduction of the infinity by assumption, rather than by consequence.
  - lisper 10y ago
    I think you're missing the point. It is not that all that information exists, it is that all that information has to exist in a single particle. This is not impossible, but it is implausible.
    - SomeStupidPoint 10y ago
      Correction: it has to be accessible to a single particle, but the information could be non-localized across the whole system, since your particle is itself fairly non-localized, and arguably has weakly interacted with the various devices along the way, meaning that Im not sure we can fully disentangle the wave-equation for the photon from the equations for the splitters. This could easily be the photon "borrowing" bits from the splitter, by sharing a non-local value with it, which carries the split path information for both. Which is just to say that the system (in full) has to be able to contain a number of bits sufficient for that, which your setup does.
      - lisper 10y ago
        > Im not sure we can fully disentangle the wave-equation for the photon from the equations for the splitters That doesn't matter. The two sides of the experiment are space-like separated, and the splitters on each side are light-like separated. There is no place the information can possibly be other than in the photons.
        SomeStupidPoint 10y ago
        ...except non-local variables. Which is why I keep mentioning non-locality. I don't think words are working and I'm not sure I understand your point fully. Could you draw a diagram? Specifically, the apparatus and where you think the requirement for information occurs. I really do want to understand your point, because it's an interesting argument, even if I'm not sure I agree.
        lisper 10y ago
        > I don't think words are working Indeed. I have no idea what you mean by "non-local variable." You should read this: http://www.scottaaronson.com/democritus/lec11.html http://www.scottaaronson.com/democritus/lec11.html just to make sure we're on the same page about the basics. (Pay particular attention to the part starting with "No-go theorems galore".)
deleted 10y ago
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lisper 10y ago

Did you not bother to read the original article? "Now an international collaboration led by Adán Cabello has invoked a fundamental thermodynamics result, the Landauer erasure principle, to show that systems in hidden-variable theories must have an infinite memory to be compatible with quantum mechanics." All I'm saying is that you don't need thermodynamics to show this. Conservation laws are enough.

SomeStupidPoint 10y ago
My point was your argument doesn't hold, because you cant actually construct a situation in which the system doesnt already have sufficient storage capacity: the inability to require those bits without already having enough bits in the system to store them is pretty important. I don't believe that it can require QM to account for arbitrary memory, without presupposing we have it to construct the device. Hence, impossible constructions dont matter. I have some similar objections to the summary of their paper, but I haven't had time to read it yet. It's possible they address some of them. In particular, measuring from an arbitrary location and an arbitrary number of times sounds like the introduction of the infinity by assumption, rather than by consequence.
- lisper 10y ago
  I think you're missing the point. It is not that all that information exists, it is that all that information has to exist in a single particle. This is not impossible, but it is implausible.
  - SomeStupidPoint 10y ago
    Correction: it has to be accessible to a single particle, but the information could be non-localized across the whole system, since your particle is itself fairly non-localized, and arguably has weakly interacted with the various devices along the way, meaning that Im not sure we can fully disentangle the wave-equation for the photon from the equations for the splitters. This could easily be the photon "borrowing" bits from the splitter, by sharing a non-local value with it, which carries the split path information for both. Which is just to say that the system (in full) has to be able to contain a number of bits sufficient for that, which your setup does.
    - lisper 10y ago
      > Im not sure we can fully disentangle the wave-equation for the photon from the equations for the splitters That doesn't matter. The two sides of the experiment are space-like separated, and the splitters on each side are light-like separated. There is no place the information can possibly be other than in the photons.
      - SomeStupidPoint 10y ago
        ...except non-local variables. Which is why I keep mentioning non-locality. I don't think words are working and I'm not sure I understand your point fully. Could you draw a diagram? Specifically, the apparatus and where you think the requirement for information occurs. I really do want to understand your point, because it's an interesting argument, even if I'm not sure I agree.
        lisper 10y ago
        > I don't think words are working Indeed. I have no idea what you mean by "non-local variable." You should read this: http://www.scottaaronson.com/democritus/lec11.html http://www.scottaaronson.com/democritus/lec11.html just to make sure we're on the same page about the basics. (Pay particular attention to the part starting with "No-go theorems galore".)

deleted 10y ago

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