4 ms·
I see the distinction you're making (I think), but I still don't see how that invalidates GP's analogy. Surely "running" a wavefunction is computationally chea
by Vraxx 10y ago
I see the distinction you're making (I think), but I still don't see how that invalidates GP's analogy. Surely "running" a wavefunction is computationally cheaper than re-evaluating the particle's characteristics at every universal frame. Perhaps it's not so much about our own "watching" but rather "do not calculate when irrelevant". My own analogy might be an online map frame like google maps, where tiles outside the viewing box are not loaded. This is because we can tell what needs to be calculated by the bounding box of the viewer without needing all the other finer details. I see it more as a lazy eval.
- comicjk 10y agoThe particle's characteristics ARE the wavefunction - or to say it another way, the wavefunction is the only real characteristic a particle has. When I run a quantum mechanics simulation at work, I might afterwards calculate the particle positions or some other classical characteristic of the system. But I need those characteristics only because I'm trying to get a classical model of the system. The system itself, when it's running, doesn't do any of that. It interacts wavefunction-to-wavefunction. As far as we know, that's how the universe works.
- wolfgke 10y ago> The particle's characteristics ARE the wavefunction - or to say it another way, the wavefunction is the only real characteristic a particle has. As far as I know not in the De-Broglie-Bohm theory (but I'm not a physicist, so correct me if I'm wrong): > https://en.wikipedia.org/wiki/De_Broglie%E2%80%93Bohm_theory https://en.wikipedia.org/wiki/De_Broglie%E2%80%93Bohm_theory > http://plato.stanford.edu/entries/qm-bohm/ http://plato.stanford.edu/entries/qm-bohm/ > http://plato.stanford.edu/entries/qm-decoherence/#PilWavThe http://plato.stanford.edu/entries/qm-decoherence/#PilWavThe
- OscarCunningham 10y agoYeah you're right, but in the De Broglie-Bohm theory the wavefunction is calculated, and then the movements of the particles are calculated on top. So from a computational perspective it's strictly harder.
- davorak 10y ago> As far as I know not in the De-Broglie-Bohm theory As a physicist I am telling you should not conclude that the De-Broglie-Bohm theory is tell you anything different than what comicjk said. > The particle's characteristics ARE the wavefunction This kind of statement is normally said to stress the fact that the best evidence and experiments indicate quantum mechanics accurately describe the physical world and even parts like superposition(single particle double slit experiment, tunneling etc) that defy more classical intuitions. De-Broglie-Bohm theory includes the same set of non-intuitive behaviors that all valid interpretations of quantum mechanics have, in other words it is not testable different from other interpretations.
- wolfgke 10y ago> De-Broglie-Bohm theory includes the same set of non-intuitive behaviors that all valid interpretations of quantum mechanics have, in other words it is not testable different from other interpretations. There exist opinions that disagree: > https://en.wikipedia.org/w/index.php?title=De_Broglie%E2%80%93Bohm_theory&oldid=740277352#Non-equivalence https://en.wikipedia.org/w/index.php?title=De_Broglie%E2%80%... "In 2016, Pisin Chen and Hagen Kleinert argued that the Copenhagen interpretation and the De Broglie–Bohm theory yield different results for the ratio of peak intensities in the double-slit experiment. They concluded that they are thus not mathematically equivalent." > http://www.ejtp.com/articles/ejtpv13i35p1.pdf http://www.ejtp.com/articles/ejtpv13i35p1.pdf
- davorak 10y agoThanks for the citation, I had not seen that recent paper(2016). Pisin Chen and Hagen Kleinert say that De-Broglie-Bohm theory does not agree with experimental results or the rest of quantum mechanics. This is surprising since there evidence of this is from a 1979 paper, their citation [15] [15] C. Philippidis, C. Dewdney and B. J. Hiley, Il Nuovo Cimento 52B, 15 (1979) can be found online(republished) at: http://www.pbx-brasil.com/FisQuan/Notas/Area01/semana041/papers/QuantumInterferenceAndTheQuantumPotential.pdf http://www.pbx-brasil.com/FisQuan/Notas/Area01/semana041/pap... I would want to do some additional research before agreeing with Pisin Chen and Hagen Kleinert that the De-Broglie-Bohm theory has been experimentally disproven. Other then combining the existing research double checking the numerical simulation and algorithms in [15] would be my approach. Pisin Chen and Hagen Kleinert paper seems to lack such an examination which would have made for a more conclusive argument.
- SiddarthaBuddha 10y agoIs it possible that the calculations you are performing afterwards are what is causing the waveform interactions to have definitive results? In other words, could the waveform interactions cause the waveforms to become coupled and cause the entire system to exist in a superposition until such time as a classical measurement is made?
- OscarCunningham 10y agoThe computational problem of simulating a wavefunction is suspected by computer scientists to be exponentially harder than simulating classical physics (this is the question of whether BPP=BQP). So quantum physics is the opposite of a computational optimisation!