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Is there any theoretical way to have physics work not like quantum mechanics?

  1. Jul 15, 2011 #1
    I asked this in yahoo, and of the answers no one addressed what I was asking, so I added details to maybe help. First ever post on here, sorry if it's bad.

    Is it theoretically possible to have energy transfers happen continuously instead of discretely? Does it lead to any problems?

    I've read on a physics site that "Planck's problem -- and the problem of all other physicists at the time -- was that there was no theoretical reason why anything should occur in whole steps, rather than smoothly. There was no reason why anything should be "quantized."

    So this implies most physicists thought that a continuous transfer of energy made theoretical sense. I'm not sure I agree with this, but am looking for what you have to say about it.

    Additional Details
    Okay, no one answered my question. Maybe I should be even more specific. Could continuous functions, like a polynomial, ever be represented in the real world? Is it possible to take it out of the abstract (mathematics) and into the real world (physics)? ie, nothing is quantized, infinite possible positions of particles, infinite possible intermediate points, infinite possible frequency of radiation... can this theoretically make sense?
     
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  3. Jul 15, 2011 #2
    Quantization comes from Einstein's photoelectric effect. Increase the intensity of the light and you keep getting more results, but continue to increase the frequency and you hit a wall where you can't get any more results.

    This is because the light consists of distinct units of energy that can only be absorbed by a single electron at a time. Increase the intensity and you increase the number of units of energy, which means more electrons get ejected from their atoms. But increase the frequency and you only increase the amount of energy carried by each unit, which means you can't eject any more electrons than their are photons in the beam of light.

    I certainly can't think of any other way to interpret this experiment than to think that light is divided into discrete units of energy, but if you can I'm sure it would revolutionize physics.

    I think our current understanding of physics assumes that some things, like energy, are quantized. Other things, like space and time, are assumed not to (although they may be).
     
  4. Jul 15, 2011 #3

    xts

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    Theoretically it is possible, even more, we use it everyday: 19th-century physics works like you say and it is a perfectly suitable for all macroscopic purposes. If you make a mechanical analaysis of new car design, you assume the energy is transmitted from the engine as contionous transmission, rather than being quantizied.

    But such approach contradict many observable phenomena, (historically) starting from photoelectric effect and spectra of elements, which become easily explainable if you accept the assumption that energy transfers are always quantizied.
     
  5. Jul 15, 2011 #4

    Pengwuino

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    Yup this basically should answer your question. It was only until we started having experiments that seemed to contract the idea of a 'continuous' universe that we actually needed the ideas behind quantum mechanics. There is nothing natural about things being quantized, it's simply how the world ended up being like.
     
  6. Jul 15, 2011 #5
    I'm sorry, I'm still not satisfied.

    I'll break this down into a much simpler example. A particle travels from A to B in a line. In math, abstractly, there are an infinite number of points between A and B. It is not discrete, it is continuous. However, in the real world is it possible to transverse those infinite set of points?

    I think it's not possible. I think it's not possible because the only way to cross the infinite set of points is to move an infinitesimal. How can you move an infinitesimal? If your answer is "you can't" then this is why physics is quantized. No infinitesimal energy transfers, no infinitesimal movement, no infinitesimal anything. Basically that also proves space of time are quantized. I think this is a simple idea, and I want my voice heard! God nabbit flabbit.

    A point you may bring up:

    "It's possible to have an infinite series converge to a real value, so it's possible to have a infinite set of intermediary points to travel across."

    Yes, but this is only abstractly in mathematics. We don't actually make a computation adding an infinite amount of numbers. This is impossible. We have proofs showing that it converges to a value, not a showing of a "complete addition to infinity" (EDIT: as another example, we have proofs showing pi has inifinite digits, but the only way we know this is because of the proofs, and NOT because we computed pi infinitely... that is impossible). Mathematics can't always be represented in the real world. Imaginary numbers are a good example. Are they used in QM for calculations? Yes. But they don't actually have any sense in the real world.... here have an imaginary number of apples.
     
    Last edited: Jul 15, 2011
  7. Jul 15, 2011 #6

    Bill_K

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    Apparently you won't be satisfied unless we agree with you. Nevertheless, present physical theory assumes that space is continuous and evolution takes place one infinitesimal step at a time. And this has nothing whatsoever to do with the fact that systems are quantized.
    Complex numbers are an essential ingredient in the quantum world, they're not just an artificially added convenience. Complex-valued probability amplitudes are necessary to produce interference.
     
  8. Jul 15, 2011 #7
    Well, as I said, the question of whether or not space or time is continuous or consists of discrete units is an open one. I would say that an object doesn't have to move an infinite number of infinitesimals to get from 0 to 4 meters, it just has to move four meters, because that's how I interpret the math.
     
  9. Jul 15, 2011 #8

    HallsofIvy

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    If you have ever taken a course in Calculus, you should be aware of Zeno's paradoxes- essentially what you are arguing- and how Calculus handles them.

    Frankly it sounds like you really do not know very much about what physics and mathematics are. The theory of infinite series does, in fact, tell you how to sum an infinite series.
     
  10. Jul 15, 2011 #9
    No, it's clear that no one here knows what I'm saying. I might have to just make a youtube video or something.
     
  11. Jul 15, 2011 #10
    A particle travels from A to B in a line. In math, abstractly, there are an infinite number of points between A and B. It is not discrete, it is continuous. However, in the real world is it possible to transverse those infinite set of points?

    What is you answer to this, and just this question. Your straight answer.
     
  12. Jul 15, 2011 #11
    You can't move an infinitesimal in the same way you can't reach infinity. Why is this hard to grasp?
     
  13. Jul 15, 2011 #12
    There is no straight answer to this question. All we know is that an object can move from point A to point B. We can use calculus to describe that motion in a way that hasn't broken down so far. Some day an experiment may demonstrate that space is not continuous. Or that might never happen.
     
  14. Jul 15, 2011 #13

    DaveC426913

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    It isn't hard to grasp. That doesn't make your conclusion correct.

    It is possible to cross an infinite number of infinitesimal dsitances in a finite time.

    Seriously, have you read up on Zeno's paradoxes?
     
  15. Jul 15, 2011 #14

    qsa

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  16. Jul 16, 2011 #15
    Definitely not possible if you stop at every point along the way. Definitely not possible if you stop at every OTHER point along the way. If dx-->0 then 2dx, 3dx, 4dx...ndx-->0 as long as n is not infinity.

    If you want to get from point A to point B DON'T STOP keep moving. Your continuous speed will determine how long it takes. As you consider more and more points between A and B the dx becomes smaller, no question, however if your speed is non-zero then the dt also becomes smaller, no question.

    So even if the points are infinite in number between A and B dx and dt both go to zero so it takes less and less time to travel the smaller and smaller distance.

    IMHO In the real world it is possible to transverse those infinite set of points.:smile:

    Does this particle you speak of have any length, width, or height? If it does then it would cover an infinite number of abstract mathematical points by simply existing. That is a non-intuitive idea. You can cover infinity just by being there.
     
    Last edited: Jul 16, 2011
  17. Jul 16, 2011 #16

    qsa

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    that is exactly the point, we don't know what is the real world at small distances. different theories look at it in different ways. that is why I provided the links, the issue is much more complicated than a simple analogy. it is not only about particle movement(which inherently not well defined) it is also about how energy is defined and all kind of host processes that are involved like running couplings, masses and so on. also if you read some chris Isham, although complicated, but hopefully you will get some idea of what is involved.



    http://en.wikipedia.org/wiki/Christopher_Isham
     
  18. Jul 16, 2011 #17

    Yes, I know what Zeno's paradox is. The fallacy everyone makes is that mathematical operations always represent what is possible. You cannot compute the answer to Zeno's paradox. You only can use proofs to show that an infinite set of lengths can add to a real number. That is not the same thing. I want to stress that. No one has ever added an infinite string of halfs to get the answer 1. This problem is analogous to moving to the next smallest unit.

    Exactly... abstract points. Now, please list out all the points this particle is located at. You can't do it, it's not possible to list the points. Now move the particle slightly over to the "infinitith digit". Again, not possible.
     
  19. Jul 16, 2011 #18

    DaveC426913

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    Fallacy? But we can get from point A to point B.

    So, we have an observation 'cover the infinite infinitesimal gaps from A to B', and we have a mathematical solution for it (calculus).

    What exactly is the problem here? Sounds like you're tilting at windmills.


    This is silly.

    You're making a problem where there is none. You want to set constraints on how to calculate it or do it, and then claim it can't be done. (Well duh.)

    The answer to how to do it is to do it. Move it from a to b. It moves though all intervening points. You claiming they're "abstract" does not mean we didn;t pass through them. They're real.

    The answer to how to calculate it is to use calculus, which is the math we use when dealing with infinitesimals and limits.
     
    Last edited: Jul 16, 2011
  20. Jul 16, 2011 #19

    Dale

    Staff: Mentor

    This is a good point.

    To the OP. There are two ways that a theory can be discarded, one is that it is not logically consistent with itself and the other is that it is not consistent with experiment. When you ask if something is "theoretically possible" you are asking if it is logically consistent with itself, regardless of any experimental evidence.

    Classical mechanics is logically self-consistent. So the idea that energy transfer could be continuous rather than discrete is theoretically possible. However, there is plenty of experimental evidence to the contrary.

    Also, your subsequent posts on quantized space are not really relevant to your OP on quantized energy. Current theories have quantized energy, but not quantized space, so they are completely separate questions.
     
  21. Jul 16, 2011 #20
    "Is there any theoretical way to have physics work not like quantum mechanics?"

    Let's hope so because neither QM nor GR works everywhere....so we need something new, like quantum gravity, so we can understand singularities like the big bang and the center of black holes.
     
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