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February 11th, 2013, 11:19 AM
There is a limit to the precision of pairs of properties of particles such as position and momentum that can be determined.
Does it mean that the properties are non-existent or simply cannot be determined?
Follow-up question: why can't the properties be determined?
Last edited by Parametric; February 11th, 2013 at 02:08 PM.
The properties exist (after all, we can measure them) but they have a complementary relationship so that the more accurately you know one, the less accurately the other can be known.
It is a bit like a musical note. You cannot have a pure tone that lasts for a limited time. If it consists of a single frequency then it must have infinite duration. If it is short, then it has a mixture of frequencies.
The more precisely the length of the note is defined, the greater the number of frequencies. If you give a precise start and end time, then there are an infinite range of frequencies. If you introduce some uncertainty in the start and end time (fade in and out) then the range of frequencies will decrease.
The reason the two situations are similar is because they are both Fourier transforms.
Last edited by Strange; February 11th, 2013 at 12:29 PM. Reason: improved Fourier description
Can you elaborate a little on what you mean by uncertainty makes the range of frequencies decrease in a musical note? Not sure I understand.Originally Posted by Strange
How, then, does the beam of light of a laser, having a single wavelength, in phase, and coherent, fit in with the comparison of a musical note of pure tone? They are both wave-transmitted entities, are they not?
jocular
A pure sinewave has no beginning or end (that's what the mathematical function, sin(x), says). It consists of a single frequency, so we can know it to arbitrarily high precision. Having no beginning or end, however, its position is highly uncertain.
So, you say, let me simply shrink the duration of the sine. Then I'll know its position much more accurately. But if you truncate the sinewave to, say, a single cycle (or less), you can't know if that is a piece of a single frequency sine or of a more complicated thing that behaves wildly outside of the preserved region; the situation has become uncertain. Formally, the spectral composition of a truncated sine contains more frequency components than a single-frequency sinewave; that's what a Fourier transform tells us. A chopped-up sinewave isn't the same as a continuous sinewave; they are quite different beasts. So, narrowing the sine in an attempt to know its position more accurately fundamentally diminishes our ability to say what its frequency is. Less uncertainty in one parameter necessarily comes at the expense of increased uncertainty in the other.
Note that this uncertainty isn't an artifact of some limitation in our measurement technology. It is an inherent feature of the phenomenon itself. Throw away those textbooks that tell you it's a measurement problem (most often explained, e.g., with a gedanken experiment involving a photon pinging an electron, or some such thing).
The other way of thinking about that is that a note with a well defined duration is equivalent to a sine wave multiplied by:
And to generate that"envelope" requires summing an infinite number of sine waves.Code:_____ ____| |____
Generating a slower envelope /-----\ requires a smaller number of frequencies.
Because a laser is not purely monochromatic, just very nearly.
The answer depends upon the interpretation of Quantum Mechanics you choose, in my opinion. The interpretation that I prefer is that measurement of one characteristic of a particle (exact location or momentum, for instance) involves touching the particle with a photon or interfering with possible particle motion in some way. This measurement interference changes the particle's location or momentum so that the second paired characteristic cannot be simultaneously measured. This answer is very simply and can be understood by most anyone, nothing mysterious.
Last edited by forrest noble; February 15th, 2013 at 12:24 PM. Reason: added: in my opinion
<sigh> Here we go again.
That is not what the Heisenberg uncertainty principle is about. It has nothing to do with "interpretations". It is the fundamental nature of the Fourier transform (you have a mathematics degree, so you should know that).
And wrong.This answer is very simply and ...
Absolutely, completely wrong, Forrest. Again, you don't know what you are talking about, so please don't post misleading answers, especially when correct ones have just been given.
Strange and I have already described why uncertainty is a fundamental property of Fourier transform pairs. Quantum has nothing whatsoever to do with it.
Uncertainty is not an artifact of measurement. It is inherent in the mathematics of Fourier transforms. Read Strange's and my explanations in the posts just preceding your nonsense one. In particular, read the last sentence of Post #5. I wrote it as a pre-emptive warning against exactly the widespread error that you have committed. Sadly, exhibiting the Dunning-Kruger effect is a bad habit of yours, which is why I have to continually warn readers to disregard your posts as painfully unreliable.
See http://en.wikipedia.org/wiki/Fourier_transform
and http://www.mathpages.com/home/kmath488/kmath488.htm
Last edited by tk421; February 12th, 2013 at 12:43 PM.
There is nothing like uncertainty in the universe, it is a concept that does not exist, therefore should not be treated with respect.
The quantum world is a deviation of the exactitude of the universe. When someone doesn t understand the concept of certainty, he will deviate from science and crash into the chaos of uncertain assumptioned hypothesis like qm and sgr.
And no, i will not be converted to your idealistic view of the universe, i will not blind myself from the truth. I will not change the very meaning of science just to fit in the deception world you live in. And no, science is not sgr and qm, not at all. You less into science than a kid. You disgrace everything around you. I m done here.
I really hope that is true.
now i have a far better understanding of HUP. thank you strange and tk421.
TheVoiceInside.
You know all too well that your notions about physics and the rest of science lie far outside well-established theories and principles. If you wish to argue your position, you'd do well to not start out by insulting anyone and everyone who understands physics, astronomy and cosmology.
It's one thing to say that you're done here. If you continue down this path that decision will be taken out of your hands.
Yeah. Only you know the real truth about the nature of nature. You are a prophet, sent by the FSM to enlighten us. No need for complicated math and science stuff, with all their pesky demands for evidence. Assertions by a self-confident random guy on the internet are good enough for me. Now you can go share your intellectual bounty with others elsewhere. Your job here is done.
You're welcome!
No one is trying to "convert" you into anything. Indeed, the only one here who has made firm declarations that he cannot be moved from his beliefs is you. That is fundamentally an anti-scientific position. You are certainly free to believe as you wish (and even if someone were to disagree with that, how could he do anything about it?). We are, however, well within our rights -- this being The Science Forum and all that -- to point out that your approach to knowledge is dogmatic, not open-minded.
science is based on facts that ca be proved, and you can t even prove shit that sgr and qm can actually work in the world we live in , try to work with your assumption as being science and try to predict something, you won t because you don t know shit about what science really is you don t shit about what the world really is you don t know shit.
give me one prediction that is true, that modern physics can prove, besides i can make prediction without using physics, for instance the motion of any object in the universe including macro type and micro type can be known precisely with a method that does not require any newtonian equations, i can get more with less, you can t deny that my method are surpassing yours without dmitting you are fools
It s not physics, but it s still science, it s stil a method that can determined the exact value of everything in the physics domain.
I thought you said
Go. Now. Take your meds.
Apparently I misunderstood what you meant when you said that you were "done." Evidently, pharmaceuticals were involved. I hadn't comprehended that.
Post back after they've taken effect (or worn off, as the case may be).
just die with your pills already, no one will blae you since you seem to be so less than human anyways. Goodbye!
This is a mainstream forum; even if the concepts of the Heisenberg Uncertainty Principle, Quantum Mechanics, Special and General Relativity are all wrong as you assert in your quote above, this is not the place to express such a contrary opinion or to get angry when people here assert mainstream beliefs, not even with a mountain of evidence to support your position/assertions. There are other places in the science forum for this kind or proposal, but without any attitude. Even the best arguments speak poorly of the author when accompanied by insults. Let others make the insults making their argumentative ineptitudes obvious to all, especially those knowledgeable concerning effective methods of argument and persuation. No pissing contests allowed
TheVoiceInside Please reread your #24. And, if your constitution is as strong as mine, check all your posts on all threads at your profile page.
You've earned yourself a standard holiday. One week off for a bit of R & R (and maybe a brief course at a courtesy college.)
When your week is up, if you wish to continue posting here you'll need a much better grasp of ordinary manners. A high school level of understanding of physics would also be an asset if you want to discuss such matters.
I know he's suspended, but for anyone else, the anomalous magnetic moment of the electron as predicted by QED is accurate to 12 decimal places with experiment.
Math can sometimes be very precisely derived from a long history of observations. I don't think he was disputing the math of any of these theories. Like most contrarians of mainstream theory, I expect he was primarily disagreeing with the concepts that are at the foundation of these theories. Also he said he had his own methods of determining the motions of objects precisely without using Newtonian equations. That sounds like a "New Ideas" proposal but not for hereI know he's suspended, but for anyone else, the anomalous magnetic moment of the electron as predicted by QED is accurate to 12 decimal places with experiment.
QED is, obviously, a QM theory so at its heart are these wild concepts. The example I gave is just one of many, but central to the calculation is the inclusion of a virtual photon, a purely QM effect that follows the uncertainty principle, that corrects the EM scattering of an electron from a static potential.
You obviously haven't read his posts. He is not someone you want to align yourself with, even as a fellow "contrarian".[I don't think he was disputing the math of any of these theories. Like most contrarians of mainstream theory, I expect he was primarily disagreeing with the concepts that are at the foundation of these theories. Also he said he had his own methods of determining the motions of objects precisely without using Newtonian equations. That sounds like a "New Ideas" proposal but not for here
His "method" consists of making up random numbers and when they disagree with reality claiming that reality is wrong. It doens't belong here. It doesn't belong anywhere on a science forum.
I took this opportunity to jump in.Because a laser is not purely monochromatic, just very nearly.
Something occurred to me regarding the probability wave function where the particle is spread (smeared) over a larger area and only collapses to a particle when interacting with something else.
I wonder if this probability field of a particle falls within the sine of the frequency of that probability wave or is if it can be larger than the sine of its wave function, i.e. a wave of extremely small amplitute cannot be found, even probabilistically, over a large area, i.e could it be a 2d wave?.
I think you are mixing a few things up. The wave-length of a mass particle, is of certain size, but still finite. Even a good and pure laser has a certain decoherence length, in which there is a random phase change. This can be in the order of micrometers, or even millimeters so that it doesn't affect systems under study. But everything has a finite size.I took this opportunity to jump in.Because a laser is not purely monochromatic, just very nearly.
Something occurred to me regarding the probability wave function where the particle is spread (smeared) over a larger area and only collapses to a particle when interacting with something else.
I wonder if this probability field of a particle falls within the sine of the frequency of that probability wave or is if it can be larger than the sine of its wave function, i.e. a wave of extremely small amplitute cannot be found, even probabilistically, over a large area, i.e could it be a 2d wave?.
The wavelength of the wave signifies the energy, but the size of the wave packet, which is the area which the particle is smeared out over, is a function of its fourier transform. The size of the packet is dependend on how accurately we know the energy. (that is the entire idea of the uncertainty principle). So a wave-super position is limited by this, it generally isn't much larger then the size of its largest wavelength.
But maybe I get your question wrong I am somewhat confused in what you mean to ask.
I though this might be of interest.
As more photons struck the drum, greater fluctuations occurred in the measurements recorded, distorting the readings, and proving that the Heisenberg uncertainty principle can indeed be demonstrated with objects large enough to be seen with the naked eye.
Researchers demonstrate Heisenberg uncertainty principle at macro level
I am adding to this by restricting you to Trash, New Hypothesis and Pseudo in future. Your ideas do not belong in the main sections. Continuing to post there will earn you a permanent ban. Thanks.
Ouch, my colleague is not going to like this...
Ouch, my colleague is not going to like this...The above quote from the link provided by Write4U, was explained in my posting #8. This same principle should apply also to small molecules when more than a single photon might be needed to measure the molecules position or momentum. Again, IMO there is nothing mysterious about it. Even a single photon with enough energy could change the position of a molecule that was not overly large. For the same reason one should also be able to make a calculated estimate of how large a molecule can be used for a single given photon energy level, when this principle would no longer be significant or detectable.....It was Heisenberg who famously noted that it was impossible to measure the momentum of an object and its position at the same time. As an example, he pointed out that using a microscope to look at a single electron, would require shining light on it. Those photons would cause the electron to move slightly, changing its momentum....
Last edited by forrest noble; February 15th, 2013 at 11:41 PM.
Forrest, just stop it. Please. You do not know what you are talking about. Science by quotation is not science.
You've been given the correct explanation in terms of Fourier transforms. I have shown you that uncertainty relations are inherent in the mathematics. The mathpages URL I gave you gives a compact derivation that shows how complementary quantum variables are Fourier transform pairs. Unless you can show a defect in the mathematics, uncertainty is inherent. It is not an artifact of measurement.
Your description of how Heisenberg came to his famous principle is well known. Because you are stubbornly ignorant of physics, you are unaware that Heisenberg later came to understand -- as did everyone else -- that uncertainty was not due to imperfect measurement tools. Thus, the gedanken experiment that led him to his eponymous uncertainty principle was, in fact, somewhat misleading.
Now, again, please stop posting erroneous information. Stop ignoring correct information.
I find it necessary to re-issue this standard disclaimer: Readers would do well to ignore posts by Forrest. He has no clue what he's talking about. Ignore him.
What you say may be the standard interpretation, I agree. But a second interpretation is the quote that I presented from the link provided by Write4U. If it were not a present interpretation by some then it would not have been quoted. The quote is totally in accord with Occam's razor and therefore should be a preferred explanation over the explanation you gave IMO unless there is a better reason or logic for your interpretation. Because the math may work concerning any theory, does not necessarily mean that the related theoretical concepts behind the math have validity, or that very different concepts would necessarily change the math at all. Math can often readily be derived from a 75 years history of observations like QM, even without any concepts at all. Of course many believe that the concepts of QM are out of the application realm of Occam's Razor which could enable the many illogical concepts of QM , IMOYou've been given the correct explanation in terms of Fourier transforms. I have shown you that uncertainty relations are inherent in the mathematics. The mathpages URL I gave you gives a compact derivation that shows how complementary quantum variables are Fourier transform pairs. Unless you can show a defect in the mathematics, uncertainty is inherent. It is not an artifact of measurement.
Last edited by forrest noble; February 16th, 2013 at 01:09 AM.
Instead of "standard," you should have said "rigorously correct."
There are always many "interpretations" of concepts. But that one is just wrong. I have already shown you why. You can't finesse your way out of it, Forrest. You are wrong. It is really that plain and simple.But a second interpretation is the quote that I presented from the link provided by Write4U.
Explanations of the HUP have been dumbed down to the point of being wrong. You like the simplicity of the dumbed down version, I know. But tough noogies, Forrest. Your taste doesn't mean anything. The science is what it is, whether you like it or not. It happens that, in this instance, what you like is just wrong.
Now quit arguing, quit posting more nonsense, and go read the links I provided earlier. If you cannot find an error in the math, then you have no choice but to accept what the math says: Uncertainty is inherent.
And if you still want to insist on disagreeing, then I demand that you explain how it would be possible to measure both the position and frequency of a true sinewave if you had perfectly noninvasive instrumentation available to you. If you cannot meet that demand (and you cannot), then you are acknowledging that the uncertainty has nothing to do with the limitations of your instrumentation, i.e., the uncertainty is inherent in the phenomenon itself.
Last edited by tk421; February 16th, 2013 at 12:43 AM.
Here's a relevant tidbit from your favorite source, Wikipedia:
(From the Wikipedia entry titled "Uncertainty Principle")
The references cited within that paragraph (and the rest of the article, which I advise you to read and learn) provide further explanation and support.
Bottom line: The HUP is a consequence of an inherent uncertainty in the nature of nature itself. It is not a consequence of limitations in measurement technology.
So stop propagating erroneous information.
We already know that your understanding of science is limited to the misrepresentations in the popular press. You don't need to keep reminding us. KTHXBYE
Ok, but if uncertainty can be observed at macro scale, does that mean the "vagueness" of physical objects at a larger scale than individual partcles?Here's a relevant tidbit from your favorite source, Wikipedia:
(From the Wikipedia entry titled "Uncertainty Principle")
Yes, but at macro scales it becomes so small it is irrelevant.
The theory of Fourier analysis predates QM by roughly a century. It was well understood long before QM came about, and it is a fundamental mathematical principle.Because the math may work concerning any theory, does not necessarily mean that the related theoretical concepts behind the math have validity, or that very different concepts would necessarily change the math at all. Math can often readily be derived from a 75 years history of observations like QM, even without any concepts at all.
Forrest alleges to have studied mathematics in college (I seem to recall his claiming to have a degree in mathematics). Yet he displays more than simple ignorance -- it's more of an aggressive repelling of knowledge. And when challenged, his response is always a resort to some quotation (often pulled out of context, or uttered by some dodgy "authority" to which he appeals), or a rambling philosophical dissertation that is without scientific merit or relevance.
I wish that he would simply stay out of the mainstream sections, because his posts get seriously in the way of helping those who come here in search of actual, scientific answers. He doesn't know what he's talking about, but worse, he doesn't care. So he posts crap anyway.
This is utter crap again, sorry to say. Please refrain from posting stuff like this in the main sections from now on, please. thanks.What you say may be the standard interpretation, I agree. But a second interpretation is the quote that I presented from the link provided by Write4U. If it were not a present interpretation by some then it would not have been quoted. The quote is totally in accord with Occam's razor and therefore should be a preferred explanation over the explanation you gave IMO unless there is a better reason or logic for your interpretation. Because the math may work concerning any theory, does not necessarily mean that the related theoretical concepts behind the math have validity, or that very different concepts would necessarily change the math at all. Math can often readily be derived from a 75 years history of observations like QM, even without any concepts at all. Of course many believe that the concepts of QM are out of the application realm of Occam's Razor which could enable the many illogical concepts of QM , IMOYou've been given the correct explanation in terms of Fourier transforms. I have shown you that uncertainty relations are inherent in the mathematics. The mathpages URL I gave you gives a compact derivation that shows how complementary quantum variables are Fourier transform pairs. Unless you can show a defect in the mathematics, uncertainty is inherent. It is not an artifact of measurement.
Again this quote and related link came from Write4U. The translated quote originally was a paraphrase of Heisenberg. It is not a quote from my chosen link. Whether Heisenberg changed his mind or not was not the point. The point was that how large a molecule that can be used to test this principle can be predicted by using that quote. This would be a type of proof of the validity of Heisenberg's original statement and the quote presented. You can allude to his statement as being ignorant if you wish.....It was Heisenberg who famously noted that it was impossible to measure the momentum of an object and its position at the same time. As an example, he pointed out that using a microscope to look at a single electron, would require shining light on it. Those photons would cause the electron to move slightly, changing its momentum....
From the link of Write4U: You can disagree whether such a molecular maximum size can be calculated beforehand for this experiment, and I predict that it can. The reason why I predict this is self explained by the quote and link above, my prior postings, and Strange's posting #43. There is no use arguing about it. It will happen in less than a couple of years from now. What they might conclude from this and other related experiments is another matter. I think the initial conclusion will depend upon the DOE, who is conducting the experiment, and what conclusion they are looking for
Last edited by forrest noble; February 16th, 2013 at 01:52 PM.
Of course it's ignorant. I've already pointed out -- several times, now -- how Heisenberg's gedanken experiment led to a form of the HUP, but is not actually what the HUP says. And I've shown you what the HUP actually says. Despite its being explained to you in multiple ways, you ignore the explanations. That's why you need to be ignored by other readers. You actively repel knowledge. You prefer the dumbed-down, cartoon version of physics found in press releases, popsci articles and high school "physics for poets" books.
That is reprehensible. It's bad enough that you're ignorant of math and physics. But it's unconscionable that you would actively seek to spread this ignorance to others coming here for real knowledge. Your posts should be automatically flagged as crap, or put into pseudo or trash. Lucky for you, I'm just a random guy here, not a mod or admin.
Again, please stop posting on subjects you so clearly know nothing about.
Last edited by tk421; February 16th, 2013 at 06:54 PM.
Thanks for the info Markus
I understand that, but the HUP is a direct result of the mathematics of Fourier analysis, not of the physics of QM as such.Thanks for the info Markus
The point seems to be whether Fourier Transform analysis implications should be the final word concerning interpreting the Heisenberg Principle, or whether experiment should be the final word as explained in my posting #36, Strange's posting #43, and Write4U's link in posting #33.I understand that, but the HUP is a direct result of the mathematics of Fourier analysis, not of the physics of QM as such.Thanks for the info Markus
It is nothing to do with "interpreting". The uncertainty principle arises because of the mathematics of the Fourier transform. That's it. A fundamental aspect of reality.
Experiment has nothing to do with it.whether experiment should be the final word as explained in my posting #36, Strange's posting #43, and Write4U's link in posting #33.
- Your post was just plain WRONG.
- My #43 has nothing to do with experiment and may not be taken to validate your ignorance.
- Write4U's link was to a piece of shoddy journalism.
No, the point is that you are ignorant and refuse to acknowledge when you have been shown to be wrong. On the one hand you wsh to appeal to Heisenberg's heuristic (i.e., informal, non-rigorous) argument, but you deliberately choose to reject his matrix mechancs, from which a rigorously correct statement of the HUP emerges. You can't have it both ways.
If you reject his matrix mechanics, then you are rejecting QM. Fine; but that is a distinctly personal view and has no place in the manstream section.
Stop posting crap.
Experiment and observation fully supports the HUP as it arises from the maths, which is in turned based on Fourier transforms.or whether experiment should be the final word as explained in my posting #36
Well, I am quite sure many here may, and possibly have explained this better that I can. But I studied Phy. Chem. at university when dinosaurs roamed the Earth, so let's see if I can get a handle on this.
We suppose first a quantum system that can be described by the state vector. We further suppose that the total energy of this system can written as the sum of kinetic and potential energy - this seems reasonable enough, right?
This sum is called the Hamiltonian operator acting on our state and one writeswhere the first term on the RHS denotes kinetic energy and the second, potential energy.
Now every operator known to man, beast or bacterium is entitled to an eigenvalue when it operates on a vector. E. Schroedinger showed us that when such an Hamiltonian operator acts on a state vector, the eigenvalues are all possible energies available to our system. Note that there are likely very many of these eigenvalues available.
For a particle of masslet's now set
and note that anytime an operator can be decomposed as a sum, then each summand must itself be an operator. Accordingly we promote
to tha status of an operator and write
.
Likewise, since potential energy (for a massive particle) depends only on position, we may cast the potential energy as the operator, say.
And each of these operators is entitled to its own energy eigenvalue. Suppose now I know the energy eigenvalue for the sum. then the conservation law tells me that, in the extreme, if one of these in the summand is zero the other cannot be.
But suppose I do NOT know a priori the energy eigenvalue for our Hamiltonian and further suppose I DO know this value for the operator
And conversely - if I still do not know the energy eigenvalue forbut DO know that for
I am reasonably sure this is garbled - it is while since I studied this stuff
Forgive me, but has irrelevancy been established at macro levels? Seems to me that if enough particles are affected it might translate in a macro effect. I am wondering also if QM has as yet unexplained causal properties.Strange, February 16th, 2013, 02:19 AM
Yes, but at macro scales it becomes so small it is irrelevant.Originally Posted by Write4U,
Ok, but if uncertainty can be observed at macro scale, does that mean the "vagueness" of physical objects at a larger scale than individual particles?
I am so fascinated with all of this I cannot resist probing.
Saw a program on Sci channel about new proposed properties of "color" to irreducible fundamental particles, like quarks and bosons.
Seems to me logical, that if this is the case, it might be causal to our ability for observing this "technicolor reality".
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