4 ms·

Carlo Rovelli's book Helgoland[1] is a short and accessible account of the various philosophical interpretations of quantum phenomena, along with their shortcom

Carlo Rovelli's book Helgoland[1] is a short and accessible account of the various philosophical interpretations of quantum phenomena, along with their shortcomings. Highly recommended to anyone interested in the topic. Rovelli is a proponent of what he calls the "relational interpretation" of QM, which basically states that particles only have properties when they interact with other systems (and may be better thought of as events than persistent objects). Entanglement is a general phenomenon that describes the relationship between two interacting systems and a third which hasn't interacted yet. Put another way, something can be real in relation to A but not to B. However, the correlation that entanglement guarantees ensures that previously isolated systems will see the same things if they do eventually intersect. It's different from QBism because there is no special privileging of human observers; all physical systems exist in direct interaction with some systems, are in superpositions in relation to others, etc. [1]: https://bookshop.org/books/helgoland-making-sense-of-the-quantum-revolution/9780593328880 https://bookshop.org/books/helgoland-making-sense-of-the-qua...

raphlinus 5y ago
This sounds to me not unlike the "zero worlds interpretation" in Ron Garret's talk. Are you familiar with it and would you happen to know if it's roughly the same or whether there are substantial differences? [1]: https://blog.theangry.dev/2017/01/05/ron-garrets-the-quantum-conspiracy-what-popularizers-of-qm-dont-want-you-to-know-google-tech-talk/ https://blog.theangry.dev/2017/01/05/ron-garrets-the-quantum...
- katabasis 5y ago
  If "zero worlds" means there is no unified single reality that all physical systems relate to (just like there is no universal frame of reference for motion according to relativity) then I think we're in similar territory. I'm not familiar with Garret, but Rovelli's book contains a great discussion of the "quantum eraser" experiment in that blog post, where quantum interference causes a split laser beam to recombine in different ways whether or not a detector is present. This is something you can observe with tabletop equipment apparently, a pretty visceral demonstration that quantum phenomena are a real part of our world.
  - smallerfish 5y ago
    I read Helgoland at the weekend (in a hammock at a glamping lodge in the jungle) and have been meaning since to buy some prisms to see if I can replicate that experiment. Do you happen to know if it's as simple as he describes it, or is there a trick to making it work?
    - katabasis 5y ago
      Unless you have a light source that can emit a beam consisting of only a few photons (and precise enough detectors to see them on the other side) you won't see the effect. Otherwise, the quantum interference demonstrated by the experiment will break down due to what is called "decoherence" – too many things interacting with one another will cancel out the phenomenon you want to observe. This is why we don't see quantum weirdness in our every day experience.
      - smallerfish 5y ago
        Interesting. How precise a laser would you need? And typing "photon detector" into amazon is not exactly yielding anything promising - is there equipment obtainable by somebody who's casually interested, or is this prohibitively expensive?
        katabasis 5y ago
        In Rovelli's book he talks about going to Anton Zeilinger's laboratory to see the experiment in person. I assume you'd need a proper lab with carefully calibrated equipment for something like this, but I'm not a physicist. Even so, an effect that can be demonstrated with tabletop equipment in a lab seems more intuitively real to me than something that requires a giant particle accelerator... 100 or 200 years ago a more or less average person could set up cutting-edge scientific experiments with basic equipment and patient observation – this was the modus operandi of Michael Faraday[1] for example. Sadly it seems like those days are mostly behind us now. [1]: https://en.wikipedia.org/wiki/Michael_Faraday https://en.wikipedia.org/wiki/Michael_Faraday
- naasking 5y ago
  https://en.wikipedia.org/wiki/Relational_quantum_mechanics https://en.wikipedia.org/wiki/Relational_quantum_mechanics
  - katabasis 5y ago
    This is also good: https://plato.stanford.edu/entries/qm-relational/ https://plato.stanford.edu/entries/qm-relational/
cosmophany 5y ago
Here's a paper pointing out the major differences between Rovelli's relational quantum mechanics (RQM) and QBism: https://arxiv.org/abs/2108.13977 https://arxiv.org/abs/2108.13977

raphlinus 5y ago

This sounds to me not unlike the "zero worlds interpretation" in Ron Garret's talk. Are you familiar with it and would you happen to know if it's roughly the same or whether there are substantial differences? [1]: https://blog.theangry.dev/2017/01/05/ron-garrets-the-quantum-conspiracy-what-popularizers-of-qm-dont-want-you-to-know-google-tech-talk/ https://blog.theangry.dev/2017/01/05/ron-garrets-the-quantum...

katabasis 5y ago
If "zero worlds" means there is no unified single reality that all physical systems relate to (just like there is no universal frame of reference for motion according to relativity) then I think we're in similar territory. I'm not familiar with Garret, but Rovelli's book contains a great discussion of the "quantum eraser" experiment in that blog post, where quantum interference causes a split laser beam to recombine in different ways whether or not a detector is present. This is something you can observe with tabletop equipment apparently, a pretty visceral demonstration that quantum phenomena are a real part of our world.
- smallerfish 5y ago
  I read Helgoland at the weekend (in a hammock at a glamping lodge in the jungle) and have been meaning since to buy some prisms to see if I can replicate that experiment. Do you happen to know if it's as simple as he describes it, or is there a trick to making it work?
  - katabasis 5y ago
    Unless you have a light source that can emit a beam consisting of only a few photons (and precise enough detectors to see them on the other side) you won't see the effect. Otherwise, the quantum interference demonstrated by the experiment will break down due to what is called "decoherence" – too many things interacting with one another will cancel out the phenomenon you want to observe. This is why we don't see quantum weirdness in our every day experience.
    - smallerfish 5y ago
      Interesting. How precise a laser would you need? And typing "photon detector" into amazon is not exactly yielding anything promising - is there equipment obtainable by somebody who's casually interested, or is this prohibitively expensive?
      - katabasis 5y ago
        In Rovelli's book he talks about going to Anton Zeilinger's laboratory to see the experiment in person. I assume you'd need a proper lab with carefully calibrated equipment for something like this, but I'm not a physicist. Even so, an effect that can be demonstrated with tabletop equipment in a lab seems more intuitively real to me than something that requires a giant particle accelerator... 100 or 200 years ago a more or less average person could set up cutting-edge scientific experiments with basic equipment and patient observation – this was the modus operandi of Michael Faraday[1] for example. Sadly it seems like those days are mostly behind us now. [1]: https://en.wikipedia.org/wiki/Michael_Faraday https://en.wikipedia.org/wiki/Michael_Faraday
naasking 5y ago
https://en.wikipedia.org/wiki/Relational_quantum_mechanics https://en.wikipedia.org/wiki/Relational_quantum_mechanics
- katabasis 5y ago
  This is also good: https://plato.stanford.edu/entries/qm-relational/ https://plato.stanford.edu/entries/qm-relational/

cosmophany 5y ago

Here's a paper pointing out the major differences between Rovelli's relational quantum mechanics (RQM) and QBism: https://arxiv.org/abs/2108.13977 https://arxiv.org/abs/2108.13977