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How useful is theoretical physics?

  1. Nov 29, 2013 #1
    Hi,
    I’d like to start some discussion about the utility of modern theoretical physics.
    • How important is the development of theory in the more applied fields of physics like biophysics, condensed matter? Are there relatively recent examples when a theoretical result was instrumental to the understanding of some real phenomenon?
    I understand there are open questions in hard condensed matter physics for example, but in my experience, purely theoretical papers in these fields can be quite disconnected from the realities of experiment and the most useful ideas one gets from reading is a very qualitative idea of the paper’s point.

    • Is modern theoretical physics more detail-oriented, computational, and ultimately less physically insightful than it used to be? Perhaps this is because there are less, open fundamental questions?
    Extreme points of contrast would be development of the mathematical theory of E&M, quantum mechanics, which were revolutionary for experimental and theoretical physics.

    • We seem to live in the golden age of applied science. The Standard model has its inadequacies, but are these inadequacies less relevant to the rest of science, than say those of classical mechanics were looking into 20th century physics?

    I’m sure you can detect my bias, but I’ve made some generalizations across fields and I would love to hear some specific examples of counterpoint. I thought academic guidance seemed like the best place for this.
     
    Last edited: Nov 29, 2013
  2. jcsd
  3. Dec 1, 2013 #2
    How useful is a painting by Monet or a concerto by Mozart?

    I am, of course, giving far too much credit to any aesthetic nature of theoretical physics, but it sounded better than asking what the point of a trash heap is. :tongue:
     
  4. Dec 1, 2013 #3

    ZapperZ

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    So, are you able to "understand" anything in physics without a theoretical description? I'd like an example.

    Are you able to understand why certain metals exhibit zero resistance at a characteristic temperature without the BCS theory?

    Are you able to understand why there appears to be discrete steps in the current flow of constricted 2D material without Laughlin's theory on fractional quantum hall effect?

    Are you able to explain why topological insulators behave the way they behave?

    And do you think the transistors would have been invented if Bardeen (the theorist in the trio that won the Nobel prize) didn't understand the theory of the material?

    These are all examples from the "applied" side of physics. Without a theoretical description, then you are doing what Rutherford said a long time ago. You will not be doing science, but rather, stamp-collecting.

    Zz.
     
  5. Dec 1, 2013 #4

    ZombieFeynman

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    Indeed, even understanding the integer quantum hall effect without the notion of Landau Levels (at least) seems to be a horrible proposition.

    Perhaps the bolded part above speaks more to your deficiencies, rather than the paper's.

    For what it's worth, I think there are those in the theoretical condensed matter community who may argue that experimentalists do nothing but make pretty STM pictures or grow nice samples whilst waiting for someone knowledgeable in the field to actually explain what they see.

    I'd never make such claims though.
     
    Last edited: Dec 1, 2013
  6. Dec 1, 2013 #5
    These are however all major theoretical breakthroughs. I also believe that theory is foundational to physics. My point, which I could have made more clear, is that there is a very large chance that the modern, average theoretical physics paper in the applied sciences, is not of very much use to anyone at all besides other theorists. There is a lot of computational modeling wherein one achieves some numerical results for a very specific model that has no generality at all.

    On the other hand, stamp collecting, is always useful when done properly and is hardly easy. In fact, as a stamp collector one confronts all sorts of real world problems that the theorist has a very limited idea of.

    In short, what I am saying is that modern science needs even more experimentalists than theorists than currently is the case. I acknowledge your point, but I think what your point also shows is that modern theoretical physics is not what it once was. There are probably many more theorists than is really necessary and less problems that are truly in need of a theoretical foundation.

    I'm sure you disagree.
     
  7. Dec 1, 2013 #6

    ZombieFeynman

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    Frankly, I feel like you have either done very little research or are somehow trying to troll us.

    I am in an NSF funded interdisciplinary research group. We have two material scientists (STM specialists), 3 experimental physicists (2 growth, 1 THz spectroscopy), 1 physical chemist, and two theoretical physicists, plus all of the grad students for each PI. You better believe those two theorists heavily guide the direction of the group. Their results are of direct use to the rest of the group.
     
    Last edited: Dec 1, 2013
  8. Dec 1, 2013 #7

    ZapperZ

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    Your post made no sense, and if you look carefully, you are GUESSING and making a conjecture. In other words, you made a "theory" with no experimental evidence.

    Kinda ironic, isn't it, considering what you are attempting to convey?

    Stamp collecting isn't science. It is a conglomeration of stuff without any knowledge of the interconnectedness of it. A bunch of disjointed information does not a knowledge make. It is why one needs a theory.

    You haven't been able to explain to me how you would "understand" something having an abrupt drop in resistivity without knowledge of BCS theory, Mr. Physics!

    Zz.
     
  9. Dec 1, 2013 #8
    All of science is more computationally driven than it has ever been. This does not make physics less 'physically insightful' than in the past but the type of intuition and the way one acquires physical intuition has changed for a large number of researchers.


    What do you mean by less relevant? Corrections to measurements (of known quantities) will continually be smaller as we add more significant digits, if that is what you mean.
     
  10. Dec 1, 2013 #9
    There are also quite some degrees of usefulness:

    One degree might be: do I use it in everyday life? For example, counting and writing.

    Somewhat lower is: do I need it to do my job?

    Is it useful for engineering?

    Does it help me understand something in another science better?

    Does it help me understand something in physics better?

    You should first indicate what level of usefulness you mean, only then can we say whether theoretical physics is useful or not to you. It probably won't help you much in real life (except indirectly in stuff like cell phones or computers), but perhaps there's another degree of usefulness.
     
  11. Dec 1, 2013 #10
    Could you share in more detail what you do? Specifically how theorists heavily guide the direction of the group? What are specific examples in modern (I'm talking very modern) condensed matter physics where theory really does lead experiment as you say?
     
  12. Dec 1, 2013 #11
    I mean this in the sense that there are many interesting engineering applications that can be and have yet to be discovered whether or not problems in fundamental physics are addressed. I think this was perhaps less true of the last major 'revolution' in physics, as there were serious problems with the existing classical theory at the scale of the very small.
     
  13. Dec 1, 2013 #12
    Yes, so I specifically want to talk about its applicability to developing technology, which has become more important to the way we live our lives than ever before. I want to talk about whether or not its true that theoretical physics has become less important in this regard.

    When there were still major foundational deficits in the physical sciences, a theoretical physicist could make a huge contribution that would generate incredible amount of utility for all science and technology. I no longer believe that is the case, and I want to hear about why that might be the case and if you think I'm wrong, specific examples that prove your point.
     
  14. Dec 1, 2013 #13
    I think we're talking past each other. I am not we don't need theory. I'm saying we don't need as much of it, especially when it comes to continuing to develop technology, which in my mind is the most important thing science can do for people.
     
  15. Dec 1, 2013 #14
    How modern do you need it to be? The topological insulators seems like a good example of a phenomenon no one would have looked for before the theoretical predictions (the first of which basically came 2005).
     
  16. Dec 1, 2013 #15

    ZombieFeynman

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    Honestly, why waste my time? You've done very little to demonstrate why your assertions may be correct. It doesn't seem that you have a good grasp of what is being done on the modern frontiers of physics: you have ignored anyone who brought up topological insulators or superconductivity.

    It may be YOUR opinion that developing technology is "the most important thing science can do for people", but many scientists would not agree.
     
    Last edited: Dec 1, 2013
  17. Dec 2, 2013 #16

    ZapperZ

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    This is no longer an "Academic Guidance" topic. Thread closed.

    Zz.
     
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