5 ms·

Layman here, but one thing I never understood: if we are to believe everything occurred started in a Big Bang, then why shouldn't we expect everything in the un

Layman here, but one thing I never understood: if we are to believe everything occurred started in a Big Bang, then why shouldn't we expect everything in the universe to be entangled quantum-mechanically? I feel like I'd be surprised if that weren't the case.

K0SM0S 7y ago
Entanglement is not a stable mode for particles afaik, it takes effort not to break apart. Note that it's not limited to two particles, so you have a point, but the effects would be vastly more limited in time, at least in the first degree of causality. If you however mean that any entire observable universe¹, if cosmic super-inflation is true, must be causally related and thus "pre"-determined, which may be qualified as "super"-determined in a way, then I agree (layman too). -- [1]: Should we keep -c² as the metric of spacetime, i.e. no causality beyond the light boundary (function of time, in space).
- atq2119 7y ago
  Isn't it more accurate to say that isolated entanglement is not stable? Basically any interaction with some other particle causes that particle to become entangled as well, and so you very easily get "avalanches" of entanglement that spread at the speed of light. As soon as the avalanches reaches "the observer", the observer themselves become entangled with the originally entangled particle, which means that from their perspective it looks as though they no longer are. This is similar to conditional probabilities.
  - K0SM0S 7y ago
    The math says so (and the math is right¹), but how we interpret it is another story entirely. To get back on the example of dices: we might be building a whole storytelling around "probabilistic dices" because we haven't formalized the concept of the hand behind, yet. I've always pictured entanglement as totally acceptable if you postulate an extra dimension. Then you simply have to picture a link in that extra dimension between the particles, like a 'U' crossing flatland in two 'dots' (particles) would manifest as 'entanglement' for the flatlanders. But I've really grown skeptical of all such interpretations now (mine very much included), I'd tell you honestly that I probably favor the one that seems most beautiful to me within the space of possibilities (which is what I care about and investigate, the pure science). Interpretation is belief, basically, even if your name is Schrödinger. ____ [1]: Even if eventually found to be partial as the article suggests, I think it's fair to assume any "new" quantum theory would be to QED/QCD what General Relativity was to Newton's equations of motion: precisely a generalization from which to derive Newton for small-ish quantities. Ergo, we can assume QM is 'True'.
jfengel 7y ago
That kind of entanglement doesn't really explain the Bell test results. Entanglement is unstable, and easily swamped. It doesn't go away, but it becomes a very small factor in things. If I had two entangled electrons, and added them to two coins, the two coins are now entangled. But if I flip them, I don't expect the results to be significantly correlated. The classical behavior of the coins massively swamps the entanglement. So even if you and I were performing a Bell test experiment, and know that the atoms of your brain are somehow entangled to the atoms of mine dating back to the origin of the universe, it's still unreasonable to expect that to lead us to set up the equipment in such a way as to preserve the correlations between two entangled particles in our experiment. There's just too much brain matter, and too much has happened to it from the beginning of the universe until now, for that entanglement to make a difference.
- mehrdadn 7y ago
  Thanks for the reply! So what I don't understand is, in your explanation, you appear to tacitly assume the rest of the brain matter is (in some sense, maybe statistically) "[mostly] independent" from the electrons we're measuring. As if, maybe they were behaving independently before, and only now have become a teeny tiny epsilon bit entangled due to the entangled electrons they're interacting with. But I don't understand what this assumption is based on; it seems to directly contradict the Big Bang idea. Presumably we all came from the same Big Bang, and were all completely entangled with each other at that point, with everything tied directly to everything else. Why should it be that after the particles got away from each other, this would stop being the case? I just don't understand. To me, if literally everything in the universe was entangled at some point, it will be forever—to my understanding, there's no way to "reduce" entanglement unless you have a source of particles with "less" entanglement to interact with, right? Which I understand would not be the case in this universe, because everything would be fully entangled with everything else.

K0SM0S 7y ago

Entanglement is not a stable mode for particles afaik, it takes effort not to break apart. Note that it's not limited to two particles, so you have a point, but the effects would be vastly more limited in time, at least in the first degree of causality. If you however mean that any entire observable universe¹, if cosmic super-inflation is true, must be causally related and thus "pre"-determined, which may be qualified as "super"-determined in a way, then I agree (layman too). -- [1]: Should we keep -c² as the metric of spacetime, i.e. no causality beyond the light boundary (function of time, in space).

atq2119 7y ago
Isn't it more accurate to say that isolated entanglement is not stable? Basically any interaction with some other particle causes that particle to become entangled as well, and so you very easily get "avalanches" of entanglement that spread at the speed of light. As soon as the avalanches reaches "the observer", the observer themselves become entangled with the originally entangled particle, which means that from their perspective it looks as though they no longer are. This is similar to conditional probabilities.
- K0SM0S 7y ago
  The math says so (and the math is right¹), but how we interpret it is another story entirely. To get back on the example of dices: we might be building a whole storytelling around "probabilistic dices" because we haven't formalized the concept of the hand behind, yet. I've always pictured entanglement as totally acceptable if you postulate an extra dimension. Then you simply have to picture a link in that extra dimension between the particles, like a 'U' crossing flatland in two 'dots' (particles) would manifest as 'entanglement' for the flatlanders. But I've really grown skeptical of all such interpretations now (mine very much included), I'd tell you honestly that I probably favor the one that seems most beautiful to me within the space of possibilities (which is what I care about and investigate, the pure science). Interpretation is belief, basically, even if your name is Schrödinger. ____ [1]: Even if eventually found to be partial as the article suggests, I think it's fair to assume any "new" quantum theory would be to QED/QCD what General Relativity was to Newton's equations of motion: precisely a generalization from which to derive Newton for small-ish quantities. Ergo, we can assume QM is 'True'.

jfengel 7y ago

That kind of entanglement doesn't really explain the Bell test results. Entanglement is unstable, and easily swamped. It doesn't go away, but it becomes a very small factor in things. If I had two entangled electrons, and added them to two coins, the two coins are now entangled. But if I flip them, I don't expect the results to be significantly correlated. The classical behavior of the coins massively swamps the entanglement. So even if you and I were performing a Bell test experiment, and know that the atoms of your brain are somehow entangled to the atoms of mine dating back to the origin of the universe, it's still unreasonable to expect that to lead us to set up the equipment in such a way as to preserve the correlations between two entangled particles in our experiment. There's just too much brain matter, and too much has happened to it from the beginning of the universe until now, for that entanglement to make a difference.

mehrdadn 7y ago
Thanks for the reply! So what I don't understand is, in your explanation, you appear to tacitly assume the rest of the brain matter is (in some sense, maybe statistically) "[mostly] independent" from the electrons we're measuring. As if, maybe they were behaving independently before, and only now have become a teeny tiny epsilon bit entangled due to the entangled electrons they're interacting with. But I don't understand what this assumption is based on; it seems to directly contradict the Big Bang idea. Presumably we all came from the same Big Bang, and were all completely entangled with each other at that point, with everything tied directly to everything else. Why should it be that after the particles got away from each other, this would stop being the case? I just don't understand. To me, if literally everything in the universe was entangled at some point, it will be forever—to my understanding, there's no way to "reduce" entanglement unless you have a source of particles with "less" entanglement to interact with, right? Which I understand would not be the case in this universe, because everything would be fully entangled with everything else.