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Uncertainity Principle in QM, an insight

September 27, 2008

Mohan, mdashf


A power-point slide Uncertainty Principle of nature

Read at-least the end of this article below: ‘”the additionl form of uncertainty equation is momentum-time uncertainty for mass-have particles and position-time uncertainty for mass-havenots (a photon is a mass-havenot but it does not believe in rioting in Birmingham)” YOU WILL SEE why taking pictures with modern digital cameras make some of the pictures necessarily blurred. WE have reached great sensitivities with cameras now, by reducing the time for which shutters open we have made the position very uncertain, almost as much as they exist in nature, perhaps. SO now all pictures are very sensitive to small motions and small positions where the indeterminacy of position is quite seeable in a naked eye through a digi-cam. Sanjay argues with me reg. this point, below in the comments, but now I have own this argument (he can come up with something again, I am just careful of him)  Sanjay said I am mixing ray-optics with photon-optics but there is nothing called ray-optics as long as the photon is very first moving which was always the case, but very tiny time-windows were not possible before. This is a feat of the modern-digi-cams. I can sleep well enough now, after 2 yrs of taking that picture that I found the reason to be well explainable by what we know from the advancement of our understanding, perhaps not so much 10 yrs ago when I didn’t know these modern things … (but who knows you hear a thing or two and you remember them after 15 yrs, we just go about different pursuits of life and forget many things we knew as a classic notion)

https://webmohan.wordpress.com/2011/08/14/characteristics-of-photon/

19 Comments

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  1. September 21, 2010

    It is explained in a way that non-scientist could understand.

    But I have a question about uncertainty principle. The way I understood it is: Things change because we change the property of the thing by trying to measure or observe it. Focusing camera give you a better picture than the locations that are not focused. It means our perception is accurate because we observe it (just opposite to uncertainty principle). So which one is real, the thing on focus or the one which is out of focus? Uncertainty principle says the later! But that is not true. Is it?

    • Mohan #
      September 22, 2010

      Uncertainty principle essentially means the uncertainty or the size of error is included in the nature of measurements in such a way that the state or complete picture of a physical system which has to be determined by the physical and measurable parameters are measurable to the extent allowed by such a constraint.

      You are familiar with the mathematical form of this constraint which is often given as a relation between non-interchangeable parameters and known as a commutation relation. In classical theory of motion of objects and systems these commuted that is the parameters were interchangeable but not so in Quantum theory of objects. So if one parameter is measured, to a desired degree of accuracy or precision or the uncertainty in this measurement, the measurement on the other parameter is already determined only as an inverse of the accuracy/precision/uncertainty of the first variable/parameter.

      That does not mean that the fact that we are changing the attributes of the system in which we are performing the measurement is a new-found principle. All it means is, its in the nature of measurement rather than our measurement skill, technique etc.

      That is Uncertainty principle is a principle much in the sense that gravity is a principle. That is, they both are facets of nature and our understanding is expressed mathematically. Gravity principle is an exact equation but UP is an inequality.

      It represents the fact that our measurement of nature is determined by nature to the degree of accuracy possible and not in line with any of our traditionally perceived notions or ideas. Nature’s design is like that, we like it or not.

      Now that is a result of the dual nature of objects of reality, that is atoms, electrons, molecules. Dual nature meaning both wave and particle behavior. In an article in this site, I have also mentioned how a quantum mechanical measurement is possible on as large an object as a 1 KG spherical mirror. The tiny deflection to the size of 1/100 of the size of a proton which is 1/10 size of an atom is measurable.

      So quantum effects or uncertainty principle has a correspondence to a scale even to the so called Classical Physics. That means UP of QM and in general all principles of QM ie the now mentioned wave-particle duality are all valid on large objects as well. (Just) We may not be equipped to take a note of it with our capabilities of measurement.

      So UP is a result of wave particle duality. That is, this uncertainty in measurement is a result of how objects exist in nature as a dual-object rather than any one of the manifestation of such objects which we often come across.

      A TV signal is perceived as a wave of electro-magnetic disturbance, that is, its spread in a large region and your antenna has to be spread out to receive the signal of this wave. But this same wave has its particle nature merged with it which is perceivable and also measurable as suitably decided by Uncertainty Principle.

      In my experiment where I was playing around with my camera I observed the pattern shown there, in a situation where I focused the camera at different locations and explained them. The picture or photograph is always like an “illusion” because its never a 3-D picture.

      Our eye perceives a 3D scene. But if we are to be very exact with UP then we need sophisticated detectors, write a lot of algorithm and may see the UP effect in some exact form.

      Focusing means we have additional information without invalidating any measurement. We are talking about a complex system and a 2-D project of this information from a 3D reality. If the photon has enough energy it will register a dot on the photo area. If it does not have energy enough to make a dot that is to register itself, on the screen it will appear as a dim dot or may not even have any reasonable information to convey because its almost invisible. Since for a photon, Energy is like frequency that means the corresponding wavelength will have a bad precision if Energy is registered precisely enough which would mean there is a bad knowledge about where the photon came from. (still thinking about this )

      In the situation that the position from where the photon is coming is along the z axis we do not know precisely where it comes from. (perpendicular to the photo plane) There still is a precision of the energy of this photon as decided by UP. But since we don’t care about the z axis all of them will hit the same point with varying energy.

      If there is enough light this point will be quite visible on the picture because at-least some would have the desired energy to register a point. But if the photon is going along the y axis very precise energy of the photon would mean there is a chance that an elongated wave prong in the z axis is possible, so that it has some effect on the picture screen. If there are many such photons, they will appear all along x axis with varying degree of dimness or faintness.

      That means we’ll have blurred and sharp spots simultaneously on the screen, coming from all possible directions. So we can continue to analyze how every direction will affect the screen and so on. If we can feed all the physical data into a computer then we can do a sophisticated analysis to extract any UP relation as physical evidence.

      Also by focusing (this is a speculation though because I don’t know the exact mechanism of digital camera) we are just adding additional info about the picture of the certain portion but not the complete picture. That is, additional smart techniques can increase the clarity of the picture only to certain extent. Uncertainty principle will always mean we are lacking some power somewhere to be able to measure something, but it does not mean God is playing some sort of carom game with the atoms and electrons. We know how much he likes to drive the new VW Bentley but he “definitely” isnt playing a dice here just because UP is an inequality. The God has to be as pitiful as its adherents in any case because they have no business here in the first place.

      Such methods can be used to study astronomical data, eg the experiment I showed, Gemini, they cancel the noise coming from atmosphere dust and so on. Also I think it was a picture of the first solar system outside our solar system that was just discovered when I was doing this experiment.

      • September 23, 2010

        You may disagree. Wrong in mixing up UP with a simple problem in ray optics. Parts of the photo not being in focus has got absolutely nothing to do with the quantum uncertainties in the photons! Why things are focus and out of focus is a problem of optics, not quantum mechanics.

      • September 23, 2010

        and learning more about UP and optics now to see what I can learn more..
        http://farside.ph.utexas.edu/teaching/qmech/lectures/node26.html

        UP is applied for focusing on a microscopic system, right. NOT flowers or big object where photon is not going to change the position after being interacted with these classical particle.

        http://scienceblogs.com/principles/2010/02/amazing_laser_application_4_op.php

        doi:10.1016/S0030-4018(99)00644-6 (article published)

        So please give me some more reference to make me understand the relationship between UP and particle (classical) in focus.

      • Mohan #
        September 23, 2010

        I think you are mixing up focusing and UP or QM more than necessary. Also UP is not used for any focusing. Its a principle much like gravity as I said, its there and it will show its effect not only in microscopic scale as you say also in macroscopic scale.

        Actually I have said twice, that optical and digital focusing give additional info, for example a correction of the position of many bunch of photons or in other words less amount of blur in the picture. (and if I guess correctly then digital camera can use this position info in addition to the digital info, which is exactly where the UP effect may be present)

        I am not mixing UP of QM with optics. We have reached tremendous sensibilities of atomic scale although with other detectors, if not this camera, that I have discussed. To say that UP will not show up itself in Macroscopic effects is a serious misunderstanding of all of Physics and not just QM. Ray optics and QM as you or some one else understands may be defined in the text books, differently than how I am telling you, for taking a course or two.

        But if you observe nature and apply your knowledge, there are different stories.

        And I researched a great deal, last night, I did not sleep at all, just to find answers to your question. So I expect, you read my discussions about anything and especially Physics, seriously, which you do quite often and I actually appreciate that.

        There are many lose ends in all of QM and its interpretations and UP even to this day. The links you show up above are what may be described as trash, in a Physics discussion. They are not even showing the character of language of Physicists. Actually I would read them only for different purpose eg to solve a homework in a graduate study. But their usefulness is almost zero for any serious discussions of Physics.

        That’s why I said (still thinking) about UP in this article. First of all, the photons are relativistic as well as obey UP where I still need to brush up my knowledge. And as you said here, this is not a simple problem in Ray optics. I wonder where you get this idea. If you remember in Ghatak’s text book quantum mechanics ideas are described with the example of a picture where less number of photons are used Vs a large number of photons are used. That’s still mixing up optics and QM.

        Here in this example I have shown the sharpness and blurriness is not coming from ray optics or photon optics. Its coming from (ray and photon) optics. Why don’t you see the discussion of the wave particle duality in the discussion I gave above. By the way you have to see any Physics discussion of anything nature has in the context of quantum mechanics as its an overruling theory over classical physics. Classical physics is used in, such, as day today understanding, but that’s more truck owners mechanics.

        And since resolution of camera is very high, several MPxl, you can imagine and also expect that quantum mechanical effects will be present in the picture and as there are large number of photons, they will show up clearly. Also another feature of QM Vs CM is the sharpness Vs the blurriness, this is never created in classical optics. They will be uniformly sharp or uniformly blurred because of the uniform resolution.

        But with increasing resolution quantum mechanical effects show up on classical scale and therefore with a high resolution camera no matter how high, there always will be some degree of blurriness, this is a fundamental principle of QM. Its a triumph of quantum mechanics actually.

        Extremely unfortunate QM is not taught in this way despite of huge efforts from such luminaries as Feynman. eg Uncertainty equation is not same as uncertainty principles, and there are many different forms of the former. There is actually so much in here that this is my all time favorite.

        This example through picture, and the LIGO example I talked about are two astounding example for the fact that quantum mechanical principle shows up on the classical scale. This is known as correspondence principle and was known even in 1920s (the QM effect showing up on large scale, not just macroscopic scale)

  2. September 23, 2010

    You made me more confused than ever. Uncertainty principle (it is the inability of measuring a parameter without making a change in it). It is an experimental artifact, right. I will research it where it is said in a way that is understandable for me.

    Things to learn:
    1. Uncertainty principle
    2. Quantum optical measurements
    3. How to write in systematic way!

  3. September 23, 2010

    http://www.cambridgeincolour.com/tutorials/depth-of-field.htm

    I am saying the example you give is not appropriate to explain UP. Focused and non-focused the flower does not convey the message. You can talk about UP in optics, but the example will be different. NOT THIS ONE.

  4. Mohan #
    September 23, 2010

    Dear Sanjay, Eureka. From the link above you just sent, its quite clear (along with all the discussion I had, may have confused you, but who cares, I took 2 nights to explain you) that I am brilliant. Check this out (the action of focusing is definitely trying to mess around with the act of measurement. So its not in anyway decreasing the amount of uncertainty present in the picture. Its just deciding where we are to see a more sharp picture, because that’s where we have focused.) Uncertainty principle is not an experimental artifact , focusing is. But if you remember my point in the power point slide, I had said that we may add more than one focus to a particular camera or detector, probably that technology will take more than 2 decades but in that way we can reduce the amount of uncertainty. We can not remove uncertainty principle, because this is so even with the minimum amount change we can inflict on a system. By the way who the hell are you to tell where UP can be talked about and where not. LOL.

    • September 23, 2010

      2 nights of no sleep!!! The more certain you are in explaining something, the more uncertain it becomes for me understand what you are trying to say. I guess your explanation and my ability to understand your explanation are related in a mathematical way same as uncertainty principle that cannot be removed, but reduced by using some good links or references. LOL

      Uncertainty principle exist in classical world, but just the error is 0.0000000000000000000001when math is used (no meaning to dig in)

      • Mohan #
        September 23, 2010

        Dear Sanjay,

        I care to explain a little more before my patience runs out like fuel in a car at your great lack of Physics understanding.

        1. I slept enough, I took 2 nights to research over your questions and my point is I expected you to read carefully and go through the slides enough before making hasty remarks. But to confess honestly I am wrong to expect understanding of what I am saying. Because I put in a great deal of ideas. But this is in general true about me so you may just remember for all future correspondence.

        2. This is about your lack of Physics understanding. That number you gave I don’t know what its saying. You are saying this is error which would mean Uncertainty principle is measurable in classical world more correctly than even all classical measurements.

        3. this is again similar to 2, if you mean that UP does not show up in classical world then you are saying we don’t have evidence of correspondence principle, which you may rather first make a research on. I gave one example of LIGO and this was published in a Physics Journal, my 2nd example is just good enough for any good book on Physics, where Physics principles are exhibited by real world phenomena. Actually one facet of UP is the simultaneous presence of the sharpness and blurriness which is so clear in this presentation.

        I am stopping here as I believe I must spare you from long posts as they are not satisfying your understanding.

  5. September 23, 2010

    Manmohan bhai,

    First, thank you for your effort to explain me about UP and your point of comments. I know you are doing a good research on it and passionate about explaining what you believe to be true.

    Second, I am not trying to prove you wrong. I just don’t understand the way you explain things that is complicated to me. Partly because I don’t have much knowledge about the topic and partly because of your writing that is very scattered. You may find it coherent, but not me. That’s why I asked you to give link (your choice).

    Third, I would not come here to give you a comment if I am not expecting to learn from it. I never said I am good in Physics. That’s the reason I am coming here to learn. I would not come here if I have nothing to learn.

    Forth, I will tell you what I feel or don’t understand. If you think it is “making hasty remarks ?”, then do check your own word. I am fine with you or anyone telling me what ever you think – that give me window to know more.

    Lesson learned: I don’t understand UP and need to know more

    • Manmohan Dash #
      September 23, 2010

      Dear Sanjay, Some degree of incoherence is necessary to our understanding process without which we wont be human beings but computers. The good thing I want to spread is its the ideas in Physics, not the equation. Of-course I am myself scared at the amount of uncertainty this generates in my life. Because then I have to generate a great deal of idea by studying hard pretty much anything and also everybody will question without or with understanding. In that case it takes a great deal of work from me. I don’t have Physics teaching assistants and post-docs because I like to work like a TA. But my contributions are not less than Professors. Also you can see that this slide was prepared 2 years ago and what I said I said 2 years ago(but I find that I am not wrong). What I am saying now I am saying because we are having a discussion. In understanding Physics one needs a great deal of understanding. Physics Professors usually do not argue with me because they know my approach is completely different, its intuitive and natural with a kids innocence. But you argue, which is a good thing. The thing you have to guard though is not making jokes when I am saying anything about Physics. If you check out any of my Physics articles you will see that I am not trying to make any. Because then I may run into a mushy land. And you have to give up on a constant commenting about my writing style, its more like I am speaking, isnt it. No man can change his speaking style without practicing for a decade, and still it wont change, more so with great Physicists.

  6. Manmohan Dash #
    September 23, 2010

    To add , I checked my own words and I find that what I said is not hasty but showing up. But you have to understand your and my roles here. I am showing up because you don’t seem to see up, the fact, that its you who is here to learn and of-course question, but not to remark, Also in your own words you are not good at Physics. I think you are good at Physics as long as, how long you were involved with it. Not beyond that. You know, some people, not just me, are involved with some things for eternity, to not understand them is as fine as not continuing with it. But those who are continuing with it are the ones who themselves have a great deal of doubt and uncertainty about it, otherwise they would turn their gift of gab into a law advocate or something. If you think what I am saying or writing is all scattered then make a copy for yourself and read after 2 years.

  7. September 23, 2010

    I understand what you are saying, or I am trying. I don’t think that you are listening.

  8. Mohan #
    September 24, 2010

    classic ….lets not listen to each other for a while, when we come back you will understand and I will listen

  9. September 24, 2010

    You gave me an offer than I couldn’t refuse 🙂

    Just kidding.. Go on… I am listening and watching.

    • Mohan #
      September 24, 2010

      See now we are listening each other again, but I do not know how you are watching, care to explain, oh ok, got ya, now you are winking at me for being blind huh

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