6 ms·

Quantum mechanics isn’t weird, we’re just too big [video]

peter_d_sherman 6y ago
PDS: I was watching this video, and approximately at 362 seconds into the video, we see the following chart (which I thought was highly interesting): Quantum mechanics: The Popular View o Quantum mechanics is weird! o Quantum objects can be both waves and particles: wave-particle duality. o Quantum objects can be in more than one state at once: superposition. o You can't simultaneously know exactly two properties of a quantum object: Heisenberg's uncertainty principle. o Quantum objects can affect one another instantly over huge distance ("spooky action at a distance"): entanglement. o You can't measure anything without disturbing it, and so quantum mechanics is subjective." --- But, why did I think this chart was highly interesting? Because it stacks many ideas in an area of knowledge side-to-side -- where they can be more easily be thought about at the same time! Now, the author goes on (as the rest of the video progresses) to debunk and/or set the record straight about these ideas (a few seconds after the list, a red X appears on the chart...) Now, I don't know if the author, in his views, is right or wrong; nor is this an endorsement for the video; but I think that the chart, in the way it is displayed, is highly highly interesting in the way it lays out ideas...
- deleted 6y ago
  [deleted]
crazygringo 6y ago
I'm curious about this video but certainly don't have over an hour to watch it without knowing in advance if it's worthwhile. The description (abstract) merely says: "I will show address some popular misconceptions about what quantum mechanics means, and explain what we can currently say about what it does mean." Can whoever submitted or watched this give a tl;dw for what the main takeaways are? I.e. how is this different from any other "quantum mechanics for the layperson" overview? What's new or notable about this one in particular?
- petermcneeley 6y ago
  There is nothing new or notable in this video.
drcode 6y ago
tldr: Basically a defense of the Copenhagen interpretation, i.e. "You shouldn't speculate what is happening to things you can't measure." (which is opposed to the "many worlds" interpretation, which basically boils down to "Assume the simplest possibility when discussing things you can't measure.")
- AnimalMuppet 6y ago
  If you think that's what the many worlds interpretation is, then you have a very different idea of what "simplest possibility" means than I do.
  - drcode 6y ago
    MWI just is what happens naturally if the schrodinger equation is obeyed. Every other interpretation assumes the schrodinger equation is obeyed BUT ALSO some other rules are obeyed.
    - lumost 6y ago
      The extra rules really only apply when for one reason or the other we've assumed that some exterior system which doesn't obey QM interacts with a QM system obeying the schrodinger equation. The exact border between when this is a valid assumption and we can apply extra rules to make up for it vs. an invalid assumption is ill-defined.
      - drcode 6y ago
        Rules on top of rules on top of rules
    - millstone 6y ago
      MWI makes the very strong claim that the Schrödinger equation is sufficient to explain observations that do not naturally fit into its framework, such as wavefunction collapse and the Born rule. You can simplify any theory by throwing out half its postulates. But now your theory has less explanatory power. The critiques of MWI are that it cannot explain observations. For example, consider the recent article on generating random bits through quantum fluctuations with a laser. MWI, like the Schrödinger equation, is fully deterministic; there is no randomness. The bits are not random in MWI. How to reconcile these?

PDS: I was watching this video, and approximately at 362 seconds into the video, we see the following chart (which I thought was highly interesting): Quantum mechanics: The Popular View o Quantum mechanics is weird! o Quantum objects can be both waves and particles: wave-particle duality. o Quantum objects can be in more than one state at once: superposition. o You can't simultaneously know exactly two properties of a quantum object: Heisenberg's uncertainty principle. o Quantum objects can affect one another instantly over huge distance ("spooky action at a distance"): entanglement. o You can't measure anything without disturbing it, and so quantum mechanics is subjective." --- But, why did I think this chart was highly interesting? Because it stacks many ideas in an area of knowledge side-to-side -- where they can be more easily be thought about at the same time! Now, the author goes on (as the rest of the video progresses) to debunk and/or set the record straight about these ideas (a few seconds after the list, a red X appears on the chart...) Now, I don't know if the author, in his views, is right or wrong; nor is this an endorsement for the video; but I think that the chart, in the way it is displayed, is highly highly interesting in the way it lays out ideas...

deleted 6y ago
[deleted]

crazygringo 6y ago

I'm curious about this video but certainly don't have over an hour to watch it without knowing in advance if it's worthwhile. The description (abstract) merely says: "I will show address some popular misconceptions about what quantum mechanics means, and explain what we can currently say about what it does mean." Can whoever submitted or watched this give a tl;dw for what the main takeaways are? I.e. how is this different from any other "quantum mechanics for the layperson" overview? What's new or notable about this one in particular?

petermcneeley 6y ago
There is nothing new or notable in this video.

drcode 6y ago

tldr: Basically a defense of the Copenhagen interpretation, i.e. "You shouldn't speculate what is happening to things you can't measure." (which is opposed to the "many worlds" interpretation, which basically boils down to "Assume the simplest possibility when discussing things you can't measure.")

AnimalMuppet 6y ago
If you think that's what the many worlds interpretation is, then you have a very different idea of what "simplest possibility" means than I do.
- drcode 6y ago
  MWI just is what happens naturally if the schrodinger equation is obeyed. Every other interpretation assumes the schrodinger equation is obeyed BUT ALSO some other rules are obeyed.
  - lumost 6y ago
    The extra rules really only apply when for one reason or the other we've assumed that some exterior system which doesn't obey QM interacts with a QM system obeying the schrodinger equation. The exact border between when this is a valid assumption and we can apply extra rules to make up for it vs. an invalid assumption is ill-defined.
    - drcode 6y ago
      Rules on top of rules on top of rules
  - millstone 6y ago
    MWI makes the very strong claim that the Schrödinger equation is sufficient to explain observations that do not naturally fit into its framework, such as wavefunction collapse and the Born rule. You can simplify any theory by throwing out half its postulates. But now your theory has less explanatory power. The critiques of MWI are that it cannot explain observations. For example, consider the recent article on generating random bits through quantum fluctuations with a laser. MWI, like the Schrödinger equation, is fully deterministic; there is no randomness. The bits are not random in MWI. How to reconcile these?