4 ms·

It not correlation - bell inequalities show that local variables don't explain the correlations: ie no correlated variable exists because states are decided at

It not correlation - bell inequalities show that local variables don't explain the correlations: ie no correlated variable exists because states are decided at measurement (or wavefunction collapse) time. This is why entanglement is interesting.

tbabb 9y ago
Sure, "no hidden variables" is interesting/weird. And interference is interesting/weird. And both of those things happen independently from entanglement. But entanglement itself seems very not-weird to me once you buy into those other things.
- whatshisface 9y ago
  What you're on to is that all of the big popular examples of "quantum weirdness" (uncertianty, entanglement, tunneling) emerge from a very small and elegant set of axiomatic postulates. That's the beauty of physics. One such group of postulates that chemists like to use can be found at http://vergil.chemistry.gatech.edu/notes/quantrev/node20.html http://vergil.chemistry.gatech.edu/notes/quantrev/node20.htm... . You can probably beat the elegance of those if you're willing to step further from what's actually used in calculations, but that's not what chemists like to do. Here's a better shot at being axiomatic and elegant, but it's a lot less clear (from a lay-perspective) how they relate to reality: https://en.wikipedia.org/wiki/Dirac%E2%80%93von_Neumann_axioms https://en.wikipedia.org/wiki/Dirac%E2%80%93von_Neumann_axio...
  - mikhailfranco 9y ago
    I find Lucien Hardy's discussion enlightening: Quantum Theory From Five Reasonable Axioms https://arxiv.org/abs/quant-ph/0101012 https://arxiv.org/abs/quant-ph/0101012
h2g3yhogw8 9y ago
As you're the only person so far on this thread who seems to know about this, is my understanding correct that non-locality of entanglement is because all the entangled entities are described by a single hamiltonian which means the energy expressed in each of their degrees of freedom must sum to zero, so only certain combinations of measurements are possible of the system as a whole
alpineidyll3 9y ago
Yes, but the time displaced version is more like cause and effect. Non local correlations between variables separated in time is a generic feature of classical mechanics. Frankly I think this paper exploits hype and naivete but what do I know I only have a pnas paper on quantum Dynamics.

tbabb 9y ago

Sure, "no hidden variables" is interesting/weird. And interference is interesting/weird. And both of those things happen independently from entanglement. But entanglement itself seems very not-weird to me once you buy into those other things.

whatshisface 9y ago
What you're on to is that all of the big popular examples of "quantum weirdness" (uncertianty, entanglement, tunneling) emerge from a very small and elegant set of axiomatic postulates. That's the beauty of physics. One such group of postulates that chemists like to use can be found at http://vergil.chemistry.gatech.edu/notes/quantrev/node20.html http://vergil.chemistry.gatech.edu/notes/quantrev/node20.htm... . You can probably beat the elegance of those if you're willing to step further from what's actually used in calculations, but that's not what chemists like to do. Here's a better shot at being axiomatic and elegant, but it's a lot less clear (from a lay-perspective) how they relate to reality: https://en.wikipedia.org/wiki/Dirac%E2%80%93von_Neumann_axioms https://en.wikipedia.org/wiki/Dirac%E2%80%93von_Neumann_axio...
- mikhailfranco 9y ago
  I find Lucien Hardy's discussion enlightening: Quantum Theory From Five Reasonable Axioms https://arxiv.org/abs/quant-ph/0101012 https://arxiv.org/abs/quant-ph/0101012

h2g3yhogw8 9y ago

As you're the only person so far on this thread who seems to know about this, is my understanding correct that non-locality of entanglement is because all the entangled entities are described by a single hamiltonian which means the energy expressed in each of their degrees of freedom must sum to zero, so only certain combinations of measurements are possible of the system as a whole

alpineidyll3 9y ago

Yes, but the time displaced version is more like cause and effect. Non local correlations between variables separated in time is a generic feature of classical mechanics. Frankly I think this paper exploits hype and naivete but what do I know I only have a pnas paper on quantum Dynamics.