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"What is utterly baffling and puzzling is that we only ever see one particular outcome." Actually, there is an answer to this. See e.g. https://arxiv.org/abs/q
by cjfd 6y ago
"What is utterly baffling and puzzling is that we only ever see one particular outcome."
Actually, there is an answer to this. See e.g. https://arxiv.org/abs/quant-ph/0503009 https://arxiv.org/abs/quant-ph/0503009
tldr: if information is transferred from a microscopic quantum state to a macroscopic one, one always gets a collapse of the wave function.
- prox 6y agoSo it is a bit like a wave crashing at a beachhead?
- ben_w 6y agoAny analogy we can build from everyday experience to try to explain quantum mechanics is as incorrect as any analogy a 17th century alchemist could use to explain a smartphone. The maths is what it is and does what it does, and if you play with things at that scale you can build a new intuition, but it just isn’t like the macroscopic world.
- ctdonath 6y agoQuestion then is: why does scaling up from quantum become like the macroscopic world? Just as scaling up from bits and NAND gates can become like virtual reality.
- ben_w 6y agoIt takes a degree (or equivalent effort) to understand everything on the path from NAND to VR; It looks like a similar amount of effort is needed to fully understand going from QM to macroscopic — though even that much is a guess on my part, as my QM knowledge is PBS Space Time videos on YouTube and some of the Brilliant.org courses.
- OkayPhysicist 6y agoBell curves. When you look at the distributions, it becomes pretty clear that as you add lots of particles you approach classical physics pretty quickly, because the likelyhood of the average behavior to differ from the expected behavior falls towards zero very fast.
- Enginerrrd 6y agoHonestly, assuming the linearity of QM, the many worlds interpretation also provides an answer to this IMO. Your observations, thoughts, etc, exist in the domain of eigenvalues of measurement operators applied to a quantum state and the universe itself is a massively entangled state vector in hilbert space. There is no decoherence at all. Instead, anything you can conceive of doing or measuring is actually a linear quantum operation taking a well described state in hilbert space from one state to another. What we actually see, and observe, and perceive is all just computation in the domain of the eigenvalues rather than the underlying true state of the universe as a vector in hilbert space. The fact that you remember a consistent history is because your 'remembering' is itself one such eigenvalue of a measurement operator applied to a massively entangled set of histories and you only think you get one result because that thinking itself occurs in the domain of the eigenvalues rather than the true state.