06 Feb '13 11:18>
http://phys.org/news/2013-02-probability-quantum-physics.html
Anyone have any idea what this is all about?
Anyone have any idea what this is all about?
Originally posted by sonhouseSome folks think that the double split experiment proves that photons do not exist until we actually observe them. They are just a wave form of probability. Something about our observation collapses the wave function and then they are particles. Our observation plays a part in reality which then begs the question again of whether or not if a tree falls and nobody is around, Does it make noise? I personally think it does because it is a macro system but it is a different world in the quantum realm.
http://phys.org/news/2013-02-probability-quantum-physics.html
Anyone have any idea what this is all about?
There are basically two ways theorists have tried to approach the problem of adapting quantum physics to the "real world," Albrecht said: You can accept it and the reality of many worlds or multiple universes, or you can assume that there is something wrong or missing from the theory.
Originally posted by KazetNagorraCan you do a double slit experiment where there is a measurement but not observed, but the measurement recorded for viewing later, is the disconnect from the observation by a conscious mind or does the quantum properties come into play with just a mindless machine doing the measurement?
The article is a bit inaccurate, and this guy is a bit weird.
[quote]There are basically two ways theorists have tried to approach the problem of adapting quantum physics to the "real world," Albrecht said: You can accept it and the reality of many worlds or multiple universes, or you can assume that there is something wrong or missing from the theor ...[text shortened]... physics and I fall into neither category. Surely Albrecht must know it's not that clear-cut.
Originally posted by sonhouseHumans play no role in quantum mechanics. This is more of a philosophical viewpoint than an empirical one; clearly humans can never observe something without a human interfering at some point. But to me it seems rather absurd if human intervention was required. In any case, the theory does not require it. In quantum mechanics, "measurement" can be regarded as a shorthard for "some interaction with a macroscopic system", which is as vague as it sounds. The process of wavefunction collapse is not well-understood.
Can you do a double slit experiment where there is a measurement but not observed, but the measurement recorded for viewing later, is the disconnect from the observation by a conscious mind or does the quantum properties come into play with just a mindless machine doing the measurement?
In other words would there be a difference in the result if only a ...[text shortened]... ng the results but results are available, would that be the same as the human watching anyway?
Originally posted by KazetNagorraI don't feel like getting up and looking for the book, but if I recall correctly Green offered an excellent layman's treatment of precisely this topic in The Elegant Universe. The value of a constant called h-bar determines the "solidity" of the universe; individual particles do behave unpredictably, but the value of h-bar either suppresses the magnitude of the unpredictability or the number of particles exhibiting (statistically speaking) unpredictable behavior at any one time. So h-bar is a smoothing constant, or something to that effect...how's my memory/understanding?
The article is a bit inaccurate, and this guy is a bit weird.
[quote]There are basically two ways theorists have tried to approach the problem of adapting quantum physics to the "real world," Albrecht said: You can accept it and the reality of many worlds or multiple universes, or you can assume that there is something wrong or missing from the theor ...[text shortened]... physics and I fall into neither category. Surely Albrecht must know it's not that clear-cut.
Originally posted by KazetNagorraSounds crazy to me too but it looks like it is true that observation creates reality. I never believed it until recently.
Humans play no role in quantum mechanics. This is more of a philosophical viewpoint than an empirical one; clearly humans can never observe something without a human interfering at some point. But to me it seems rather absurd if human intervention was required. In any case, the theory does not require it. In quantum mechanics, "measurement" can be regar ...[text shortened]... but I prefer to look at it as regarding the system + measurement rather than the system.
Originally posted by sasquatch672I'm not sure what you're aiming at, but h-bar, or the reduced Planck's constant, is an important constant of nature used frequently in quantum mechanics. Roughly speaking, you will notice quantum effects at the scale of h-bar.
I don't feel like getting up and looking for the book, but if I recall correctly Green offered an excellent layman's treatment of precisely this topic in The Elegant Universe. The value of a constant called h-bar determines the "solidity" of the universe; individual particles do behave unpredictably, but the value of h-bar either suppresses the ...[text shortened]... h-bar is a smoothing constant, or something to that effect...how's my memory/understanding?
Originally posted by KazetNagorraExcept now they are finding quantum effects in biological molecules and such also. It is getting a lot closer to macro size now, the effects we notice.
I'm not sure what you're aiming at, but h-bar, or the reduced Planck's constant, is an important constant of nature used frequently in quantum mechanics. Roughly speaking, you will notice quantum effects at the scale of h-bar.
Originally posted by sonhouseAm right in thinking photosynthesis requires a quantum effect to operate ? (I think the source was The Naked Scientist)
Except now they are finding quantum effects in biological molecules and such also. It is getting a lot closer to macro size now, the effects we notice.
Originally posted by KazetNagorraI don't think what you are saying is quite true - although I agree with the bit about the universes existence not depending on observers. But the theory is not the thing itself. A theory is a way of predicting results of experiments to some degree of precision and hopefully for a qualitative insight into the system of interest. In the theory of Quantum Mechanics all the operators correspond to physically observable things, so observers are built into the theory from the start. Things like the phase aren't observable so the theory is required to be invariant under a change of gauge. This is a different statement to "the universe doesn't exist if we're not around to observe it." which is nonsense based on confusing the theory with the thing the theory is about.
Humans play no role in quantum mechanics. This is more of a philosophical viewpoint than an empirical one; clearly humans can never observe something without a human interfering at some point. But to me it seems rather absurd if human intervention was required. In any case, the theory does not require it. In quantum mechanics, "measurement" can be regar ...[text shortened]... but I prefer to look at it as regarding the system + measurement rather than the system.
Originally posted by KazetNagorraHowever, for example Penrose said clearly that "the behaviour of the seemingly objective world that is actually perceived depends on how one's consiousness threads its way through the myriads of quantum-superposed alternatives", oh well;
No. There is no reference to a human or conscious observer anywhere in quantum theory.
Originally posted by KazetNagorraCorrect -and the much-quoted idea that quantum physics says that something only exists when observed is not only a myth but is a piece of pure metaphysical unscientific claptrap.
No. There is no reference to a human or conscious observer anywhere in quantum theory.
Originally posted by humyI think you're very brave, didn't many top scientists level a similar criticism of quantum theory when it was first suggested?
Correct -and the much-quoted idea that quantum physics says that something only exists when observed is not only a myth but is a piece of pure metaphysical unscientific claptrap.