Originally posted by Arbitrageur
The model of quantum mechanics is one of the best models ever because it makes so many accurate predictions. However it's a model:
* Models of Science are useful maps which approximate Nature....
If you've seen an experiment where a wave-like behavior is observed when a large object like a human is fired through the double slit, please cite the
experiment, because I'd like to see it.
The nuances of how these three models of quantum mechanics, Newtonian mechanics versus relativity overlap with each other can be described both
verbally and mathematically, but it's no more appropriate to try to say quantum mechanics is a good model at all scales than to say that Newtonian
mechanics works well at the speed of light.
That's a great list, Arbitrageur - I really like that. I think it hits the nail on the head. It's important to see models as models, and recognise
I think you may be underestimating QM though. The correspondence principle is integral to quantum mechanics. I think it's much much more than a
description of how the models overlap. Once the principles of quantum mechanics are understood, the whole of Newtonian physics follows from them
absolutely, via statistical mechanics, chaos theory and other such methods of analysis of complex systems. I would argue that there is no 'overlap' at
all. Newtonian physics is precisely the special case of quantum mechanics applied to large objects.
In your question about firing humans through double slits, you're asking "why has nobody yet observed at large scales the phenomena that QM describes
as being observable at small scales?" If instead you asked "what does QM describe as being observable at large scales", you'd get precisely what you
More generally, the whole of QM and the whole of relativistic mechanics and field theory is predicted by quantum field theory. QFT is the daddy.
The scope of quantum theory does not reach any fundamental limitations (or, for that matter any notable discrepancy between theory and experiment)
until it meets the cosmic scales at which General Relativity is important. And even then, the mismatch between QM and GR are theoretical. There are no
measurable phenomena to give us insight into anything about their nature.
With one rather notable exception - the coming into existence of the universe!
Returning to firing humans through slits: you need only calculate the de Broglie wavelength of a human to see why this could never be observed. The
phenomenon must become less pronounced and less observable as size increases. But the experiment has nevertheless been done with large molecules such
as bucky balls, and the race to perform the double slit experiment successfully using a live virus is very much on:
But yes, it is still just a model. Making sense of it, and interpreting the paradoxes that appear to crop up in any philosophical analysis (but far,
far less in the quantitative predictive analysis), is a very tricky business, and I'm sure it's still in its infancy. The hubris (and the idiocy) of
What the Bleep was to present opinions with varying degrees of flakiness as if they were all real and significant insights. The result was a seriously
misleading pile of tosh.
The structure of the quantum field theory is currently best approximated by the Standard Model, which certainly has its limitations. Again they're
theoretical - even these still not been definitively observed. The LHC reaches right up to the top end of the SM. Most physicists hope it reaches
beyond, but it's only a hope.
Finding a better model will be an extremely difficult job. The list of criteria you've given is a good one to judge them by. I just wanted to add that
I think it's easy to underestimate the scope of quantum theory.
My personal feeling is that when the experimental limits of the Standard Model are found, its successor will be another QFT. There are many brilliant
and promising QFTs (and QFT-like things) waiting in the wings, being nurtured to reveal their special talents.
The architecture of quantum field theories in general is astonishingly simple for the power of what they can describe. I think it'll be a long while
before we can honestly rely on anything deeper and more faithful in its role of reflecting the way things are.
edit on 7-2-2011 by Bobathon