# Thread: Is the Uncertainty Principle only an scale problem?

1. ## Is the Uncertainty Principle only an scale problem?

Stephen Hawking says that quantum mechanics itself is deterministic, and it is possible that the apparent indeterminacy really is because there are no particle positions and velocities, but only waves.

So for Stephen Hawking, the uncertainty principle is only aparent, but not real (?)... is another way of seeing the Universe...in other scale ...were beings and laws are different!!!

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Originally Posted by dapifo
Stephen Hawking says that quantum mechanics itself is deterministic, and it is possible that the apparent indeterminacy really is because there are no particle positions and velocities, but only waves.

So for Stephen Hawking, the uncertainty principle is only aparent, but not real (?)... is another way of seeing the Universe...in other scale ...were beings and laws are different!!!
If you keep pushing your idea, you will get into trouble. I've seen it happen before.

Also, you and I don't have the same understanding of deterministic. If every part of the universe has but one fate, that simply means that quantum mechanics is incomplete. It does not imply new laws to compliment the existing ones.

3. I think you might be confusing two different things.

Quantum mechanics describes things in terms of wave functions which define the probability of, say, the location of a particle. However, when you measure the position, you can measure it as accurately as you wish; there is no probability at that point. There are, perhaps, interpretations where this is deterministic. However, this probabilistic nature is "real"; it seems to be a fundamental part of the way the universe works.

The uncertainty principle, on the other hand, says that if you measure the location precisely then you cannot know the momentum precisely (and vice versa). This is "real" in the sense it is a fundamental limit, not just a problem with our measuring instruments, for example.

Neither of these are related to scale (except that quantum effects become increasingly more significant at small sizes).
Last edited by Strange; 2012-Jul-29 at 05:17 PM.

4. Originally Posted by ShinAce
If you keep pushing your idea, you will get into trouble. I've seen it happen before.

Also, you and I don't have the same understanding of deterministic. If every part of the universe has but one fate, that simply means that quantum mechanics is incomplete. It does not imply new laws to compliment the existing ones.
I am not pushing any idea...IŽam just trying to clarify some dubts and lacks I have with state of the art concepts... and trying to see if them fits better having a look from other point of view.

Uncertainty Principle has been always for me an strange and unintelligible concept... and always I though that was only a problem of measuring instruments...because we try to mesure them (location and momentum) precisely with inappropriate instruments larger than required).

5. Originally Posted by Strange
I think you might be confusing two different things.

Quantum mechanics describes things in terms of wave functions which define the probability of, say, the location of a particle. However, when you measure the position, you can measure it as accurately as you wish; there is no probability at that point. There are, perhaps, interpretations where this is deterministic. However, this probabilistic nature is "real"; it seems to be a fundamental part of the way the universe works.

The uncertainty principle, on the other hand, says that if you measure the location precisely then you cannot know the momentum precisely (and vice versa). This is "real" in the sense it is a fundamental limit, not just a problem with our measuring instruments, for example.

Neither of these are related to scale (except that quantum effects become increasingly more significant at small sizes).
Just for it ....If Quantum mechanics describes things in terms of wave functions which define the probability ... there are not any position and momentum to determining !!!.... That is the point !!!... there are not any precisely location...only the waves and the probability to be in one point...!!!

Concerning that quantum effects become increasingly more significant at small sizes is what I understand by "different laws could govern (due to harder effect) at different scales".

Also Gravity effect becomes decresing less significant at small scales (due to coupling with the quantum effects )

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Originally Posted by dapifo
Just for it ....If Quantum mechanics describes things in terms of wave functions which define the probability ... there are not any position and momentum to determining !!!.... That is the point !!!... there are not any precisely location...only the waves and the probability to be in one point...!!!

Concerning that quantum effects become increasingly more significant at small sizes is what I understand by "different laws could govern (due to harder effect) at different scales".

Also Gravity effect becomes decresing less significant at small scales (due to coupling with the quantum effects )
You still dont understand. Once you measure the wavefunction, it takes on a specific value. If it is position you are measuring, then once you measure it, you know the postition precisely.

The uncertainty principle says that there is an inherent limit on knowing two things at once. The classic example is position/momentum, where if you know one, there is a limit to how well you know the other. This does not limit how well you can determine one, just that there is a limit on how well you can determine both at once.

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Dear dapifo,

I was of (somewhat) the similar opinion---until it was pointed out (over and over and over)---given the position or velocity--let's say for sake of argument---no one can determine both---one will collapse (as a measurement) is made of the other.

You might try reading Feynman's take on it.----IMHO---> he explains it best----> and even admits that "no one truly understands QM"

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Quantum mechanics does not care about the size of things(or the distances involved). A photon is just as weird over the length of an atom as it is across the length of a galaxy. If you have a box with a single electron in it, you will never find the electron touching the wall, no matter how big the box is. Energy is conserved on all scales, the uncertainty part of it is that the conservation holds for long periods of time.

See? The uncertainty principle also applies to energy/time, instead of just position/momentum. It's not a single thing that only works on the quantum level. It's universal. The same laws apply on all scales. Thinking different causes an immediate problem. Where is the boundary between scales? Is it at 10 feet, 100 feet, 856.4 feet? Does the visible spectrum literally end at an exact wavelength, even when there are people that can still see beyond it? Electromagnetism is divided into scales for ease of recognition, but it's all the same photons.

I have to admit, you do have a certain 'style' in your posting. It's quite unique.

9. Originally Posted by dapifo
Stephen Hawking says
Maybe you should stay off the Hawking for a while and read some other (popular) physics book.
I think Hawking is a great scientist, but I also think that a lot of his popular work is creating more confusion under the laymen than that it actually explains.
As said above, maybe you should take up Feynmann.

10. Originally Posted by dapifo
Uncertainty Principle has been always for me an strange and unintelligible concept... and always I though that was only a problem of measuring instruments...because we try to mesure them (location and momentum) precisely with inappropriate instruments larger than required).
It is nothing to do with measuring instruments (and certainly nothing to do with their size). It is because the two parameters (position/momentum, or time/energy, for example) are related by a Fourier transform.

Fourier transforms are also used in signal processing. So, for example, the shorter a signal is, the greater the range of frequencies it contains. On the other hand, if you want to have a single frequency then the signal must be infinitely long. As you pin one of frequency or time down, the wider the other gets. The same applies to pairs of values in quantum mechanics.

11. Originally Posted by dapifo
there are not any position and momentum to determining !!!

I don't know why you say that. Clearly, all particles have momentum and position. Even photons.

12. Originally Posted by John Jaksich
Dear dapifo,

I was of (somewhat) the similar opinion---until it was pointed out (over and over and over)---given the position or velocity--let's say for sake of argument---no one can determine both---one will collapse (as a measurement) is made of the other.

You might try reading Feynman's take on it.----IMHO---> he explains it best----> and even admits that "no one truly understands QM"
Which book of Feynman do you recomend?....What mean IMHO?

13. Originally Posted by ShinAce
Quantum mechanics does not care about the size of things(or the distances involved). A photon is just as weird over the length of an atom as it is across the length of a galaxy. If you have a box with a single electron in it, you will never find the electron touching the wall, no matter how big the box is.
I donŽt understand what do you mean here....

Originally Posted by ShinAce
Energy is conserved on all scales, the uncertainty part of it is that the conservation holds for long periods of time.
What do you mean by...the conservation holds for long periods of time

Originally Posted by ShinAce
See? The uncertainty principle also applies to energy/time, instead of just position/momentum. It's not a single thing that only works on the quantum level. It's universal.
Please, give me an example for larger scales (> 10^0)

Originally Posted by ShinAce
The same laws apply on all scales. Thinking different causes an immediate problem. Where is the boundary between scales? Is it at 10 feet, 100 feet, 856.4 feet? Does the visible spectrum literally end at an exact wavelength, even when there are people that can still see beyond it? Electromagnetism is divided into scales for ease of recognition, but it's all the same photons.
I never said that there are boundaries between scales (???)....but yes that to different scales the phisics laws works some different (because different fields have more or less effort / power / relevance...but they are all consistents in all scales and dependent between them...although we still cannot link/involve / cover Gravity with the other (EM, S and W).

Originally Posted by ShinAce
I have to admit, you do have a certain 'style' in your posting. It's quite unique.
I donŽt know what do you mean with"style"... but I hope that you like it !!!

14. Originally Posted by Strange
I don't know why you say that. Clearly, all particles have momentum and position. Even photons.
Just, because yiu said it "Quantum mechanics describes things in terms of wave functions which define the probability of, say, the location of a particle".

Really, it is true that in QM describes things in terms of probability....I agree on it

15. Originally Posted by dapifo
Just, because yiu said it "Quantum mechanics describes things in terms of wave functions which define the probability of, say, the location of a particle".
And that wave function defines the probability of the particle having a particular location or momentum; so I don't understand why you say these things do not exist.

16. Originally Posted by dapifo
What mean IMHO?
In My Humble Opinion

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Originally Posted by dapifo
Which book of Feynman do you recomend?....What mean IMHO?
IMHO stands for: in my humble opinion.

You can try Six Easy Pieces---it is derived from lectures--->his lectures are difficult, also---> but "Six Easy Pieces" currently stands out in my memory

Take comfort in the fact that most Entry-level graduate students in chemistry or physics (on rare occasion) perform around the 60- 70 th percentile (at best) for their entrance level exams in QM.

I took mine more than once and only did well after studying Feynman (third volume of his lecture series) over a lengthy Summer study session.

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You could also try The Character of Physical Law---a very well written book.

You will know that you may have some grasp of QM if you can complete problem sets out of a P. Chem text or Physics text without memorizing the answers before hand on an exam.

As many have noted ---> this subject is not for the faint of heart.

Dreams of a Final Theory: The Search for the Fundamental Laws of Nature (Steven Weinberg 1993),
Parallel Worlds (Michio Kaku 2004)

In addition to the physical I studied at the University----

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One thing which I remember from my Undergraduate days in the States is that---> one must start with the Fundamentals and work up from there and I don't mean to imply anything---> but some popular accounts tend to water down fundamental and some important aspects of a theory.

If one needs an understanding of QM from a popularization ---> I would start with someone who is known for his/her understanding of QM---> Feynman is one

Another is Werner Heisenberg's: The Physical Principles of Quantum Theory---although the level is aimed at a practicing physicists of the early 20th century. I read it 2002 and remember having some comprehension of it.

I look at it now and it may take me a few moments (at least???) to get up to speed.

If you truly wish to have a deep appreciation of the subject--it must be read and practiced---that is why I mentioned performing problems. It forces you to think about the subject on a deeper level.

I am truly unsure of how you envision QM---it should not be taken for granted....maybe I sound over-enthused on the subject.

My main background is synthetic organic chemistry---not physics nor astronomy--and I am late to the subjects. Depending on one's age and experience---educating one's mind should not be approached lightly in this day and age with the speed of scientific advancements.

I hope this makes some sense?

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## Off shoot question?

Does a Classic Popularization belong in standard curriculum or standard understanding of physics or physical science?

Feynman's three volumes?

(aforementioned) Heisenberg?

If anyone can think of any other---please chime in?----and if not ---why not?

22. OK...thanks..I have a lot of things to read....

But I donŽt agree with "Experimental results always precede theory . . ."... aloso could be the other way

23. Originally Posted by dapifo
But I donŽt agree with "Experimental results always precede theory . . ."... aloso could be the other way
No, that's the scientific definition of theory. If it's not backed up by experimental evidence, it's a hypothesis, not a theory.

24. Originally Posted by Noclevername
No, that's the scientific definition of theory. If it's not backed up by experimental evidence, it's a hypothesis, not a theory.
OK...theory yes...but hypotesis no...black holes, higgs boson,....

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Originally Posted by dapifo
OK...theory yes...but hypotesis no...black holes, higgs boson,....
Both have experimental evidence, so what is the problem?

26. Originally Posted by dapifo
Uncertainty Principle has been always for me an strange and unintelligible concept... and always I though that was only a problem of measuring instruments...
No, it is a strange concept, period. It is a strange concept for physicists as much as anyone else. It's just something you have to accept.

27. Originally Posted by korjik
Both have experimental evidence, so what is the problem?
That the Theory forsee them existence !!!

28. Originally Posted by Jens
No, it is a strange concept, period. It is a strange concept for physicists as much as anyone else. It's just something you have to accept.
AMEN

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Originally Posted by dapifo
That the Theory forsee them existence !!!
And the theories that forsaw them had ample experimental evidence also. Still not seeing a problem.

To a large degree, the procedure hypothesis, experiment, then theory is a loop, not a line. Most theories have things to say about hypothesis that havent been experimented on yet. As many hypothesis probably come from 'what does this theory say about this situation' as come from 'Huh, that's funny'

30. Originally Posted by Jens
No, it is a strange concept, period. It is a strange concept for physicists as much as anyone else. It's just something you have to accept.
The difference is that physicists have developed a language for concisely and unambiguously discussing what's going on so they can communicate with each other without getting confused by the strangeness.
It's called mathematics, and if one doesn't know how to describe quantum phenomena mathematically, it's impossible to make predictions about how things behave because the strangeness is too much to understand in other terms.

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