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The math behind quantum mechanics, even though working nicely in practice, doesn't fully connected to the real world because the measurement problem has yet to

The math behind quantum mechanics, even though working nicely in practice, doesn't fully connected to the real world because the measurement problem has yet to be solved. I would say this reason is the main source of confusion.

ahelwer 5y ago
It's possible some new paradigm will come along which makes the mathematical model of quantum computation obsolete and renders irrelevant the question of interpretation (QC uses naive Copenhagen by convention) but I wouldn't hold my breath. And even then, like Newtonian mechanics, the mathematical model would probably still be worth learning.
- TchoBeer 5y ago
  I don't think QC uses naive Copenhagen by convention? I remember reading something by a quantum computation scientist (maybe it was Scott Aaronson?) who said he prefers many works.
  - ahelwer 5y ago
    What a researcher prefers is different from how quantum programming languages are structured and how the mathematical model is taught: you have a state vector in superposition that is collapsed probabilistically to classical values on measurement.
    - meroes 5y ago
      It is interesting though behind the scenes of this description, David Deutsch really does think the worlds of MWI are interfering with each other to allow quantum computations.
PeterWhittaker 5y ago
Consider reading Carlo Rovelli's "Helgoland", which is a good introduction both to Rovelli (a brilliant, poetic, and humble writer) and to Relational Quantum Mechanics, of which he is a major proponent and likely founder. Why? Because he asserts that there is no measurement problem, and that the EPR paradox and violations of Bell's Inequality don't exist: They are based on misunderstanding what QM is actually predicting and what QM observers are actually observing. Likewise, there is no wave function collapse, no need for MWI, no hidden variables, etc. To sum up the physics, badly.... Background: Relativity took as its principles that physics is universal (the universe is isotropic), that there are no fixed reference frames (all measures of speed, and therefore of a few other things, like energy) are relative to the observer making the measurement), and that the speed of light is a fixed constant. From that we space-time curvature, etc. Relational QM takes this same perspective: Measurement is relative to the measurer, which can mean an observer or anything else affected by whatever is manifesting itself, like another particle, e.g. Manifesting is a deliberate word: Absent manifestation, nothing has properties. Properties only make sense in the context of interactions. What is the charge or spin of an isolated electron? 無 (mu): the question makes no sense, because charge and spin and everything else only arise, are only measurable, in interactions. So take EPR: There is no paradox, because when Alice measures the spin of one of the entangled particles, she may "know" that Bob will measure or will have measured opposite spin, but she doesn't "know" this yet unless and until she interacted with Bob. It is only after this slower-than-light communication that the two opposite spins - and the predictions of QM - are confirmed. Until A and B interacted, entangling their states, the states A-observes-S1 and B-observes-S2 were independent. The interaction between A and B, state "A+B share information re S1+S2", took place without anything ever being FTL, without violations of locality, etc. What I do not yet know, and have not had enough to look into, is whether and how Relational QM might or does change what we expect of quantum computing. At some point, I'll seek out some Aaronson on the subject, e.g. Read the book, well worth it.

ahelwer 5y ago

It's possible some new paradigm will come along which makes the mathematical model of quantum computation obsolete and renders irrelevant the question of interpretation (QC uses naive Copenhagen by convention) but I wouldn't hold my breath. And even then, like Newtonian mechanics, the mathematical model would probably still be worth learning.

TchoBeer 5y ago
I don't think QC uses naive Copenhagen by convention? I remember reading something by a quantum computation scientist (maybe it was Scott Aaronson?) who said he prefers many works.
- ahelwer 5y ago
  What a researcher prefers is different from how quantum programming languages are structured and how the mathematical model is taught: you have a state vector in superposition that is collapsed probabilistically to classical values on measurement.
  - meroes 5y ago
    It is interesting though behind the scenes of this description, David Deutsch really does think the worlds of MWI are interfering with each other to allow quantum computations.

PeterWhittaker 5y ago

Consider reading Carlo Rovelli's "Helgoland", which is a good introduction both to Rovelli (a brilliant, poetic, and humble writer) and to Relational Quantum Mechanics, of which he is a major proponent and likely founder. Why? Because he asserts that there is no measurement problem, and that the EPR paradox and violations of Bell's Inequality don't exist: They are based on misunderstanding what QM is actually predicting and what QM observers are actually observing. Likewise, there is no wave function collapse, no need for MWI, no hidden variables, etc. To sum up the physics, badly.... Background: Relativity took as its principles that physics is universal (the universe is isotropic), that there are no fixed reference frames (all measures of speed, and therefore of a few other things, like energy) are relative to the observer making the measurement), and that the speed of light is a fixed constant. From that we space-time curvature, etc. Relational QM takes this same perspective: Measurement is relative to the measurer, which can mean an observer or anything else affected by whatever is manifesting itself, like another particle, e.g. Manifesting is a deliberate word: Absent manifestation, nothing has properties. Properties only make sense in the context of interactions. What is the charge or spin of an isolated electron? 無 (mu): the question makes no sense, because charge and spin and everything else only arise, are only measurable, in interactions. So take EPR: There is no paradox, because when Alice measures the spin of one of the entangled particles, she may "know" that Bob will measure or will have measured opposite spin, but she doesn't "know" this yet unless and until she interacted with Bob. It is only after this slower-than-light communication that the two opposite spins - and the predictions of QM - are confirmed. Until A and B interacted, entangling their states, the states A-observes-S1 and B-observes-S2 were independent. The interaction between A and B, state "A+B share information re S1+S2", took place without anything ever being FTL, without violations of locality, etc. What I do not yet know, and have not had enough to look into, is whether and how Relational QM might or does change what we expect of quantum computing. At some point, I'll seek out some Aaronson on the subject, e.g. Read the book, well worth it.