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aditya23456
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how would this world appear like if energy,time &&& momentum,distance can commuate...and anyone please describe relation between energy and time
tiny-tim said:a more realistic question would be …
how would the universe be if Planck's constant were very much smaller?
Ger said:More realistic yes. But than it would make no difference at all. Typical QM effects would be much smaller. The maths do not change. Convinient is to substitued h=c=1 in the maths to get rid of those many constants in formulas.
Ger said:All other things scale with the values proposed for h and c. Set the light speed at a 300 km/hr and special relativity will become a part of daily life
bhobba said:And you don't think that would be change in how the universe behaves?
Thanks
Bill
Ger said:Does the setting of h=c=1 change something in the maths employed? I don't think so. Only a value of h=0 (removes the uncertainty at all) would defintly change the physics, as does it do for the maths as well.
The behaviour of the universe is one of changes which we try to measure and can observe. That is described by excatly the same maths as before. So why should behaviour change?
We can set some of the constants to 1 if we choose, but we cannot set them all to 1 without changing the universe. This is because the constants can be joined into unitless numbers, like the fine structure constant "alpha", and if a number has no units, then we are not free to choose its value. So you can set h=c=1, but the fine structure constant also depends on the charge of the electron, so you would then have to take that charge to be the square root of 1/137, you have no choice. So the problem is, what do we mean by h being "small"? Small compared to what?Ger said:Does the setting of h=c=1 change something in the maths employed? I don't think so. Only a value of h=0 (removes the uncertainty at all) would defintly change the physics, as does it do for the maths as well.
The behaviour of the universe is one of changes which we try to measure and can observe. That is described by excatly the same maths as before. So why should behaviour change?
tiny-tim said:a more realistic question would be …
how would the universe be if Planck's constant were very much smaller?
See this paper here, from the American Journal of Physics, for an attempt to prove that the operators like position and momentum cannot possibly commute, and thus quantum mechanics is in some sense necessary. (Actually, he doesn't show that the operators don't commute, rather he tries to show the equivalent statement that such operators cannot have simultaneous eigenstates.)aditya23456 said:how would this world appear like if energy,time &&& momentum,distance can commuate...and anyone please describe relation between energy and time
Vanadium 50 said:No, one can calculate this. Now, one also has to be a bit careful, because one needs to carefully specify what is being held constant and what is not. But given that, it is calculable.
Vanadium 50 said:What is the difference between being able to calculate something and knowing what it looks like?
Ken G said:I would still say that if you calculate something using certain postulates, and obtain a result that does not make it possible for you to exist, then your calculation has no meaning because you know the postulates do not approximate anything useful or physically meaningful. What does it serve you to do a calculation that you know results in a useless conclusion? It would be incorrect to say "in my calculation, the universe would be like X" if X does not include a person who can do that calculation-- the conclusion that the universe would be like that, based on application of that physics, is then internally inconsistent and meaningless. Instead, you could calculate the range in h for which quantum mechanics could be the correct physics of any universe, and say that outside that range, you know quantum mechanical calculations cannot mean anything. Typically, such ranges are astonishingly narrow! The same argument can be leveled as a criticism as a concept of a "multiverse" being used to "explain" why we find ourselves in such narrow ranges.
lugita15 said:Does anyone have any thoughts on the paper I cited in post #17?
The point is that what is demonstrably true is that an intelligence (or call the computing agent anything you like) is necessary to do that calculation. So I am not assuming anything to make this claim-- rather, it is those who like to imagine that calculations exist independently from the intelligence that did them who are making the assumption. They are assuming that I can use the laws of one universe to operate a brain that can do a calculation that will then have something to say about the laws of physics in some other universe. But there is no basis for that assumption, for it is demonstably internally inconsistent (one set of physical laws is drawing conclusions about some other set of physical laws). That's why it has to be possible to do the calculation within the universe in question for it to have any meaning-- otherwise, we are only assuming that it has meaning though we know it is not consistent.ImaLooser said:It could be leveled as a criticism, but not all that convincingly. I don't see why the calculation has to be done by a being that is inside that universe and is meaningless if done outside that universe. I don't see what difference it makes.
My feeling was that it did contain insights, but it had about two pages of insights embedded in 15 pages of text, which made it a little hard to read! I can see what bhobba is saying also, I feel that these insights can be packaged in different ways and it's good to be exposed to them in any package. But what is still missing is a really concise version that cuts right to the heart of the issue. I think I would start with the idea of superposition of probability amplitudes-- once we establish that our theory will have that structure, the rest pretty much follows from fairly natural requirements (like bhobba's need to have continuous possible states evolving smoothly into each other).lugita15 said:Does anyone have any thoughts on the paper I cited in post #17?
Ken G said:(one set of physical laws is drawing conclusions about some other set of physical laws).
If you hold that physical laws govern behavior, which is quite central to the kind of thinking behind the multiverse, then you hold that physical laws govern the drawing of conclusions, because that is a behavior also. Indeed, multiverse thinking, being entirely rationalistic, must hold that nothing does anything except physical laws.ImaLooser said:? Physical laws can't draw conclusions.
Ken G said:If you hold that physical laws govern behavior, which is quite central to the kind of thinking behind the multiverse, then you hold that physical laws govern the drawing of conclusions, because that is a behavior also. Indeed, multiverse thinking, being entirely rationalistic, must hold that nothing does anything except physical laws.
The Uncertainty Principle, also known as Heisenberg's Uncertainty Principle, is a fundamental concept in quantum mechanics that states that it is impossible to know both the exact position and momentum of a particle at the same time.
If there was no Uncertainty Principle, the universe would operate in a deterministic manner, meaning that the exact position and momentum of all particles could be known at any given time. This would have a significant impact on the behavior of matter and the laws of physics as we know them.
No, quantum mechanics would still be relevant as it explains many other phenomena such as wave-particle duality and quantum entanglement. However, the absence of the Uncertainty Principle would change our understanding of these phenomena and how they operate.
Technology would likely be very different without the Uncertainty Principle. Many modern technologies, such as transistors and lasers, rely on the principles of quantum mechanics and would not function in a universe without uncertainty. Additionally, the development of new technologies and materials would be hindered without our understanding of quantum mechanics.
While the Uncertainty Principle has been extensively tested and is a fundamental principle in modern physics, there have been some attempts to challenge or modify it. However, these attempts have not been widely accepted by the scientific community and the Uncertainty Principle remains a crucial concept in understanding the behavior of matter at the quantum level.