A very basic question about Heisenberg Uncertainty

[atyy]

I mean no disrespect but in my opinion that's what anyone who didn't ever question quantum mechanics do.

But actually, you are not questioning quantum mechanics enough! You can find the great physicists questioning quantum mechanics much more than you, Take for example, Dirac's essay http://blogs.scientificamerican.com...volution-of-the-physicists-picture-of-nature/. Among the major problems he mentions is the "role of observation" or the measurement problem. It is interesting that he says it is too difficult to solve at the moment (1963), but he hopes it will go away if quantum mechanics is falsified by data some day.

At present, quantum mechanics is not falsified by any data, and is consistent with all observations we have made except for dark matter and massive neutrinos, but those can probably be accommodated by quantum mechanics.

The first breakthrough in the measurement problem was Bohmian Mechanics. The Bell theorem is another breakthrough, showing an essential nonlocality if reality exists (with some loopholes, the major ones being superdeterminism and retrocausation).

 

[VantagePoint72]

No, non locality does not violate the everyday conception. Because you can observe magnets, wireless communication, the interaction of planets. Even though you don't know why, you can actually observe that some objects can affect others from distance instantly (Although its not actually instant, you can't tell the difference. But when you add Maxwell in it, it even sounds more logical to have those effects due to some moving "invisible" things.). Thus its not weird, I know, and have seen that its possible.

Well, you've pretty much proved my point. All the phenomena you list are things that were discovered to be local after all. This is described by Maxwell's equations for the first two, and Einstein's field equations in general relativity for the last one. The lesson was that doing something "over here" causes the effect to propagate out at or lower than the speed of light through a field. The field than acts on something "over there". Nothing instantaneous, despite what Newtonian physics once seemed to imply. You "not being able to tell the difference" between instantaneous and actually instantaneous is a great, giant chasm of difference. "Non-local" doesn't mean due to some moving invisible things, it means something over here instantaneously affecting something over there. You've demonstrated, as I suggested, that those unfamiliar with relativity tend not to actually see anything wrong with this. However, this is a lack of familiarity with physics on your part, not a failure of imagination on ours. Now, the non-locality of quantum mechanics is a bit different and does not actually violate the letter of the law of relativity (though probably the spirit of it). However, you cannot hope to understand modern perspectives on quantum mechanics without first understanding the background.

I mean no disrespect but in my opinion that's what anyone who didn't ever question quantum mechanics do.

This is tremendously arrogant. Physicists have been questioning and trying to attack quantum mechanics with all its strange implications from every angle for a century. We believe it because it has held up. If you honestly think you are the first person (or at least the first in this thread) to say, "This is very strange, can reality really be like that?" then you are being ridiculous and have completely the wrong attitude to learn something. All of us have asked that. The difference is that we then went and learned physics and realized that reality doesn't care about our preconceptions of how it ought to work.

 

[DrChinese]

I mean no disrespect but in my opinion that's what anyone who didn't ever question quantum mechanics do.

I mean no disrespect, but what you are saying is closely akin to Einstein's position in 1935. So you are in good company even if a few years behind. :-) I would strongly recommend that you read the EPR paper (Einstein is the E), in which he claims Quantum Theory must be incomplete (much as you say):

http://www.drchinese.com/David/EPR.pdf

That led to Bell's paper nearly 30 years later, which is what everyone else here is influenced by.

http://www.drchinese.com/David/Bell_Compact.pdf

You can judge it for yourself. Or if you want to read a simple explanation of Bell, I might suggest one of my web pages:

http://drchinese.com/David/Bell_Theorem_Easy_Math.htm

Of course experiments such as below support the QM side in this debate. Once you are up-to-date on this area, your questions will be more meaningful. Until then, it may as well be 1935.

http://arxiv.org/abs/quant-ph/9810080

 

[PeterDonis]

But if you sum them up for any second, and consider say last 100 years, at least couple random and really weird stuff should have happened.

Your estimate of the order of magnitude of the probability of such a macroscopic "weird" event is way, way off. Macroscopic objects contain a lot of quantum particles--on the order of $10^{25}$ to $10^{30}$ of them, and all of them would have to act "weird" in exactly the same way at exactly the same instant for a macroscopic "weird" event to happen. Even a rough upper bound on the probability of that happening in a single Planck interval would therefore be something like 2 to the power $10^{25}$. There are about $10^{50}$ Planck intervals in a year, so the probability of it happening in a year would be $10^{50}$ divided by $2^{10^{25}}$, which works out to about 1 in $2^{10^{25}}$ per year (since the $10^{50}$ in the numerator is far too small to matter). That's a lot smaller than 1 in 100 or so per year ("a lot smaller" is actually a vast understatement, even with the italics).

 

[Ken G]

To add to that, there are many everyday circuits that require "weird" things to happen-- no doubt the computers we are typing this into and using to communicate would simply not work if they were forced to never do anything "weird," like having a single particle do something that has a very small probability for any macro system to do. So we find that reality as we know it involves an important combination of the fact that large groups of things have a much more limited access to "weird behavior", for essentially probability reasons, than individual particles do.

So the issue here is not that we should believe anything we are told about quantum mechanics, and are being too easily fooled by ideas that violate our preconceptions. At issue is when to drop our preconceptions when faced with overwhelming evidence of the need to do just that.

 

[DennisN]

I mean no disrespect but in my opinion that's what anyone who didn't ever question quantum mechanics do.

Neither I mean any disrespect, but you can be very sure that quantum mechanics have been thoroughly questioned, and will continue to be questioned. As an example, it happens very frequently on this forum! Trust me, I HAVE questioned QM (but it was a long time ago, and not here on this forum). But I've also always been a big fan of the experimental side of things, so when experiments all point in the same direction, then I do not find it particularly philosophically hard to appreciate the theory. Generally, regarding "questioning", I see questioning as part of learning (and maybe the beginning of learning), but to start to get into the scheme of things, you must sooner or later become familiar with the theory and the experimental facts.

If you honestly think you are the first person (or at least the first in this thread) to say, "This is very strange, can reality really be like that?" then you are being ridiculous and have completely the wrong attitude to learn something. All of us have asked that. The difference is that we then went and learned physics and realized that reality doesn't care about our preconceptions of how it ought to work.

Nicely put. :)

Ozgen Eren, I also think Feynman formulated it rather well (and fun) IMHO:


EDIT: Here is a longer clip from the QED lecture by Feynman:

 

[ChrisVer]

No, non locality does not violate the everyday conception. Because you can observe magnets, wireless communication, the interaction of planets. Even though you don't know why, you can actually observe that some objects can affect others from distance instantly (Although its not actually instant, you can't tell the difference. But when you add Maxwell in it, it even sounds more logical to have those effects due to some moving "invisible" things.). Thus its not weird, I know, and have seen that its possible.

affect others from distance instantly... Well I can tell you for sure that the Sun you see is not the Sun "now", but the Sun 8 minutes ago, and this can be explained by the speed of light (so you CAN indeed tell the difference and explain it). This becomes even more terrible to not-take into account when you look at cosmological redshifted objects. So you are not questioning science, you are trying to defy it.

And no relativity is also not casual for me, as I haven't seen anything that had a time difference with me. Actually I haven't seen any proof that time itself exists. Its a pretty valid claim for the things that are too small to observe without interfering or close to speed of light, I'm not arguing with that.

Probably then you never heard of the experiments that have verified Relativity (from cosmic muon decays to Hafele-Keating experiment). You are still trying to defy science and not question it by making such statements.

All I'm saying is that, there should be a huge evidence that rules out every other claim to give up conceptions like that. That's why I'm approaching with full suspicion on quantum mechanics, not to its accuracy on experiments but to its main perception. It makes me wonder, if every subtle position jump is possible, we should be able to observe at least 1 really weird thing on macro scale. The probability for me to suddenly appear on somewhere else is really really low, I agree. 0,0...as many zeros as you would like...0001 maybe. But every second, there are almost infinitely many random events with really low probability. But if you sum them up for any second, and consider say last 100 years, at least couple random and really weird stuff should have happened.

Probably if you do that in a macro-scale, the time you will find will over-exceed the age of the universe. A very small probability can reach times like this. Take for example the case of particles that appear to have a lifetime greater than the age of universe- and they are particles (like protons) filling up this world. We haven't ever observed them decaying.

I am sure both quantum physics and relativity and all other weird theorems works almost perfect with experimental data. All I want to be sure is that the world actually cannot be expressed in terms of what we have already seen.

Since they do, and they haven't been disproven, a scientist has to accept them, even if it goes against his logic. Otherwise scientists wouldn't look at reality, but they would try to be logically correct [like philosophers]. For every statement, there should be an experiment to prove it wrong or right. If it is proven right, you have to accept that statement or any other that gives the same result.

He did a better everyday conception than most actually. Everyone were able to see "huge rounded bulks" on the sky and everything drops to the ground, whenever they are free on air. This was an everyday conception. The apple moving towards the ground with no apparent connection is something almost everyone have seen. I mean he could have suggested that some particular objects pushed each other, but not all. I claim that you can make a theory experimentally work if you plug enough rules in it. That's what he didn't do. He used three laws and both were somehow familiar and casual(observed by any human). All I am suspecting is that, are we looking for few trivial and strong postulates and derive the rest or are we just making up a new rule in addition to what already is there.

And it was a good idea to write down those 3 laws, but then we observed points that those laws were not predicting. GR took over that law for gravitational pulling. And I never saw the curvature of spacetime, but I saw the perihelion precession of Mercury, the deflection and the gravitational redshift of light... That's what a scientist does.

I mean no disrespect but in my opinion that's what anyone who didn't ever question quantum mechanics do.

It depends on how the question is written. In general, a question of perception is carrying certain assumptions. If one of the assumptions is wrong, then your questioning won't lead you to a fruitful result. When logic tells you A and nature gives you B, then you can't impose A because that's how you understand it. Also when you question in an insisting way, you'd better have looked deeper in what the current science has to say.