Quantum Physics: recent theories (General)

by David Turell , Sunday, May 27, 2018, 20:20 (2370 days ago) @ dhw

DAVID: No one has solved any of the reality problems. It is the basis of the universe. I cannot shrink this down with any sense of continuity. About a 10 minute read and perhaps worth it if you mind being confused:
https://aeon.co/essays/what-really-happens-in-schrodinger-s-box?utm_source=Aeon+Newslet...

dhw: I decided to take the plunge, and have cherry-picked two quotes which greatly appeal to me. The first of these recognizes the reality we know and can test. For me it is absurd to assume that this is somehow less real than something we simply do not understand. That is why I invite all the theorists to step in front of a bus.

1ST QUOTE: If we cannot get a coherent story about physical reality from the Copenhagen interpretation of quantum theory and we cannot get a scientifically adequate one from many-worlds theory, where do we turn? We could, as some physicists suggest, simply give up on the hope of finding any description of an objective external reality. But it is very hard to see how to do this without also giving up on science. The hypothesis that our universe began from something like a Big Bang, our account of the evolution of galaxies and stars, the formation of the elements and of planets and all of chemistry, biology, physics, archaeology, palaeontology and indeed human history – all rely on propositions about real observer-independent facts and events. Once we assume the existence of an external world that changes over time, these interrelated propositions form a logically coherent set; chemistry depends on cosmology, evolution on chemistry, history on evolution and so on. Without that assumption, it is very hard to see how one might make sense of any of these disciplines, let alone see a unifying picture that underlies them all and explains their deep interrelations and mutual dependence.
If we can’t allow the statement that dinosaurs really walked the Earth, what meaningful content could biology, palaeontology or Darwinian evolution actually have? It’s even harder to understand why the statement seems to give such a concise explanation of many things we’ve noticed about the world, from the fossil record to (we think) the present existence of birds, if it’s actually just a meaningless fiction. Similarly, if we can’t say that water molecules really contain one oxygen and two hydrogen atoms – or at least that something about reality that supports this model – then what, if anything, is chemistry telling us?

The second quote suggests the precise opposite to what you have claimed, David. Maybe quantum reality is not the basis of the universe at all.

That is not the sense of what I get from all the reading I've done. The basis of all the particles that form matter is quantum mechanics.

dhw: 2ND QUOTE: Quantum theory was developed to explain the behaviour of atoms and other small systems, and has been well tested only on small scales. It would always have been a brave and perhaps foolhardy extrapolation to assume that it works on all scales, up to and including the entire universe, even if this involved no conceptual problems. Given the self-contradictions involved in the extrapolation and the profound obstacles that seem to prevent any solution of the reality problem within standard quantum theory, the most natural assumption is that, like every previous theory of physics, quantum mechanics will turn out only approximately true, applying within a limited domain only.

Once again, I can only thank you for all the research you do, which provides an ongoing education for me and, I hope, for others too.

Glad you liked reading it, even if it is all a strange mystery.