On Friday, April 03, 2015 8:03:12 AM Rich Freeman wrote: > On Fri, Apr 3, 2015 at 7:06 AM, Peter Humphrey <pe...@prh.myzen.co.uk> wrote: > > On Friday 03 April 2015 06:58:38 Rich Freeman wrote: > > > >> I'm not convinced that anybody has proven that quantum behavior is truly > >> non-deterministic > > > > But it must be, surely, since it's probabilistic. I don't see how the domain > > of probabilistic behaviour can overlap the domain of deterministic > > behaviour. > > /me looks over at his handy Plinko board. > > Just because it looks probabilistic, doesn't mean that it is. Take a > cryptographic PRNG. If you know the seed, the output is completely > deterministic. If you don't know the seed, you could describe the > output as probabilistic, and it might look non-deterministic, but it > still is.
There's an explanation for uncertainty that makes common sense. Let's say I throw you a ball, you can catch it because you take many measurements of it's location and your brain tries to predict it's path. But this only works because the ball is so massive and the photons that we use to see it are massless so the effect of them colliding with the ball is neglible. Imagine if the only way you could "see" the ball was by throwing another ball at it and seeing where it landed, it would then be nearly impossible to predict it's path because everytime you measure it you'll get it of course, so the principle of uncertainty would hold even though the ball was really on a well defined path. See http://en.wikipedia.org/wiki/Uncertainty_principle#Heisenberg.27s_microscope Some claims still boggle my mind (superposition in macroscopic objects), like the "tunning fork" (probably a quartz crystal) experiment on this page: http://en.wikipedia.org/wiki/Quantum_superposition#Experiments_and_applications But that's just one sentence stating that the tuning fork can be in a superposition of the vibrating and non-vibrating state but I'm sure if you find more info about the experiment is not as fantastic as it sounds. If we ever figure this to be wrong it'll probably just obsolete quantum physics so instead of deterministic quantum computing we'll have something else. > The biggest problem I have with quantum mechanics is that there is no > understanding of underlying mechanisms. We have models that describe > experiments, which is great, but not really a satisfying solution. I That's the problem with science in general. The one thing it may never be able to answer is "why?". Take gravity as an example. We got really good models for it, we can predict how it influences even light with great accuracy but what are the underlying mechanisms? We may never know. Einstein would say it's because matter bends space, but what is the underlying mechanism for that? We just take his word for it because he gave us equations that work better than anything else we've come up with so far. -- Fernando Rodriguez
