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Relativity Finally Meets Quantum Theory?

prion86 writes "Physisist Fotini Markopoulou Kalamara (try saying that 3 times fast) believes she has found a way to blend relativity with quantum theory. The article can be found on the Scientific American site."

26 of 420 comments (clear)

  1. The real challenge... by Da+Fokka · · Score: 4, Interesting

    The physicists who can make stuff like this comprehensible to laymen like me (like Stephen Hawkings) are the ones that really deserve a Nobel prize.

    1. Re:The real challenge... by packeteer · · Score: 4, Interesting

      Essentially quantum mechanics and relativity only work if certain things are true about the universe. Those certain things conflict with each other so they cant both be correct.

      All this is really about is loop quantum gravity (LQG) vs. string theory (M-Theory). String theory has been getting closer to making the world make more sense but in this article its just another competing theory.

      --
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    2. Re:The real challenge... by Tharsis · · Score: 5, Funny

      Wow.. you must be really smart to be calling Stephen Hawkings a layman ;)

    3. Re:The real challenge... by Dark+Lord+Seth · · Score: 4, Funny

      Stephen Hawkings doesn't make it understable for laymen originally, they just rigged his voice box to a thesaurus and voila...

  2. Clarification... by grahamlee · · Score: 5, Informative

    Just like to point out that what she's doing is combining relativistic gravitation with quantum physics to produce the physicist's holy grail - quantum gravity.

    Merely mixing relativity and quantum theory has been done for years and years - the form of the strong nuclear force was found by Yukawa to be a solution of the Klein-Gordon equation - which was proposed in 1924. The relativity papers were published in 1905, 1908.

    OK, so I haven't actually clarified anything at all, have I?

    1. Re:Clarification... by grahamlee · · Score: 4, Informative

      Yeah, that had me stumped too. As capybara points out, all of the relativity stuff in the article is about special relativity (light cones, can't go faster than c, etc). Even Maxwell's equations of electromagnetism could combine quantum theory (they turn out to be the wave equation for a photon, though Maxwell didn't know this :-) and relativity. In fact it was the invariance of Maxwell's equations under transformation of velocity (that is, if you boost your frame of reference by a velocity v, light still seems to be travelling at c relative to you) that led Einstein to postulate SR. And as I originally said, there has been a relativistic version of the Schrodinger equation for as long as the classical version.

      The juicy bit - and the bit that's worth a Nobel prize or few - is linking General Relativity (GR) with quantum physics. Once this is done, gravitation is unified with the other fundamental forces, physics is complete and I can go and find a proper job :-)

    2. Re:Clarification... by guybarr · · Score: 4, Informative


      Merely mixing relativity and quantum theory has been done for years and years - the form of the strong nuclear force was found by Yukawa to be a solution of the Klein-Gordon equation - which was proposed in 1924.

      True that, but even SR and QFT have serious fundemental problems.

      TTBOMK the EPR paradox and the basic definitions of what
      exactly constitutes a measurement and when/why/how does the
      WF collapse simultaneously (remember "simultaneous" is a
      non-existing term in SR) are still unresolved.

      these are not "show-stopper" bugs in that people do exact,
      experimentally tested calculations with known theories.
      But they mean that although mixing QM and SR has been done for years,
      A consistent unifying model is not available.

      (unless this QLC stuff, which is new to me, does satisfyingly
      address those issues.)

      --
      Working for necessity's mother.
  3. Physisist? by varjag · · Score: 5, Funny

    Physisist Fotini Markopoulou Kalamara (try saying that 3 times fast)...

    Try saying "physicist" once, and slowly.

    --
    Lisp is the Tengwar of programming languages.
  4. Not to troll... by brsmith4 · · Score: 4, Insightful

    but when was the last time any of us has seen a woman, let alone a woman that looks like that in our physics departments? I don't know about the rest of your schools, but my University's Math and Physics departments are completely devoid of females both on the student and faculty level. I think something like this could finally tell that majority of women that feel that they just can't do stuff like that, that in fact, they can, and that they can do it well.

    Honestly, how many of you would not be totally stuned if a girl looking like that introduced herself to you (first big surprise :) and then stated that she works in the Physics field with QM and Relativity? I know I would be.

  5. Metaphysical physics.... by foniksonik · · Score: 4, Interesting

    "It's a beautiful thought: we each have our own universe. But there's a lot of overlap. "We mostly see the same thing," Markopoulou Kalamara explains, and that is why we see a smooth universe despite a quantized spacetime."

    Personally I like this version of unified relativity but I'm very certain that there will be many nay-sayers concerning her metaphysical POV of light cones and spin networks as personal and individual interpretations of the universe... though it is really nice to hear a published physicist speak about overlapping collective conciousness and the impact on perceived physics of the universe.

    --
    A fool throws a stone into a well and a thousand sages can not remove it.
  6. Quantum observers by sunnytzu · · Score: 4, Informative

    I may still be a plain old physics student, but even I know that using the standard interpretation of quantum mechanics, as she appears to, to create an entire cosmology, is very problematic. The standard interpretation is beset by massive difficulties in the form of the measurement problem, and most other intepretations are far more successful in dealing with this. The Everett interpretation (sometimes referred to as the 'Many-Worlds' interpretation, although this ascription is inaccurate in several ways) is the one most commonly used by quantum cosmologists, and with good reason, as it does actually allow for a quantum state vector to be applied to the universe. The standard intepretation, however, does not allow for such an assignation, it is nonsensical to talk about it in the standard interpretation, a point which seems lost on the writer and perhaps even the obviously very intelligent physicist. Maybe they both should have attended philosophy of physics 101.

  7. Re:Cooking? by Ripplet · · Score: 4, Insightful

    Well she does talk about it like she's cooking:

    ' she says, "to take this ingredient and another one there and stick something together."'

    The author simply extended her own analogy. What's wrong with that?

    --

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  8. Stereotype are appropriate by bfinuc · · Score: 4, Insightful

    The real point to the whole article is that she's a hot chick. There's lot's of speculative ideas floating around about how to resolve the differences between relativity and quantum Mechanics. The discussion has been running since the twenties.

    She may well have some contribution to make, but that's not how you get your picture in a magazine. You get your picture in a magazine by looking good. I used to work as a TV cameraman, and we always interviewed the hottest chicks we could find. Why not? They have opinions too. And they draw audiences, thus spreading the word.

    "A spoonful of sugar helps the medicine go down / In the most delightful way" as Mary Poppins put it.

    So sexist remarks are very appropriate. Pile'm on.

    --
    I bragged about my Karma at a job interview but I didn't get the job.
  9. The REAL articles... by doru · · Score: 5, Informative

    ...can be found in the arXiv database. A search for Fotini gives ten results between 1997 and 2002, most of them published in well-known journals, such as Phys. Rev. D, Nucl. Phys. B etc. Not that I understand any of it, by the way...

  10. Perhaps related... by Naerbnic · · Score: 4, Interesting

    This reminds me of a theory put forth by Stephen Wolfram in "A New Kind of Science" (or, possibly from someone else earlier). Imagine that the universe was actually a huge cellular automota, where every concievable location in space-time is a cell. If you start drawing lines between these cells, you get a network which is perhaps similar to the system described by the article.

    What is interesting is that this can explain the "light cone" phenomenon as well. If we are given that a cell can only be affected by those cells adjacent to it in the network, there is a theoretical fastest response of a system, depending how often the "steps" of the automota occur, and how far reaching are these network edges. For example, if we had two nodes 3 edges away from each other in this great graph, it would take at least 3 "ticks" for either cell to affect the other. Perhaps this is the concept she's using, but with actual physical concepts instead of some abstract idea of cells?

    --


    So there I was, juggling apples and small animals, when I accidentally bit into the wrong one...
  11. Re: Noether , Mitner by guybarr · · Score: 4, Interesting


    If it turns out she's right, a whole new generation of scientist will grow up thinking that women are only good with kitchen-related things

    only ignorant people think so even today.

    STW for Emma Noether's and Lisa Mitner's stories.

    (Lisa Mitner was like an underdog^2 : both a jewish and a woman
    in the pre-Nazi regime. So off the Nobel went to who was very
    probably the less-deserving coleague)

    --
    Working for necessity's mother.
  12. Loop Quantum Gravity by anandrajan · · Score: 5, Informative

    Some of the players in loop quantum gravity (LQG) before Kalamara are Abhay Ashtekar, Lee Smolin, Carlo Rovelli, John Baez and Chris Isham. Also, Julian Barbour has written a cute semi-popular book called The End of Time on the subject as has Lee Smolin---Three Roads to Quantum Gravity

    --
    Anand Rangarajan anand@cise.ufl.edu
  13. Stephen Hawking by spakka · · Score: 5, Funny
    The physicists who can make stuff like this comprehensible to laymen like me (like Stephen Hawkings) are the ones that really deserve a Nobel prize.

    I suspect people haven't yet forgiven him for creating the Daleks.

  14. Re:Cooking? by Citizen+of+Earth · · Score: 5, Insightful

    Why are women always associated with cooking? Maybe she does cook well but that's not the point of the article... so why open and close it with that?

    It looks like the cooking analogies CAME FROM THE SCIENTIST HERSELF. Perhaps you should try to convince her to act less stereotypically feminine -- because you say so.

    --
    Correct spelling of "Glass Ceiling": C-H-I-L-D-R-E-N.

  15. Re:Uhm, maybe I'm being silly, but... by sunnytzu · · Score: 5, Interesting

    Such a mentalistic approach to quantum mechanics is a fairly odd approach to take. For starters, it seems to be much more anthropocentric than we would usually like physics to be, indeed when Wigner first suggested a mentalistic theory of wave function collapse in the 1950s, people thought he had gone mad. The other problem is identifying exactly what kind of mind counts as an observer; does a rabbit observe? Maybe we want something more intelligent than that? How about a chimpanzee? If we start at this point, then we simply ask ourselves, how about if we made the chimpanzee a tiny bit less intelligent, an infinitessimally small amount less. Do we still want to allow him to be an observer? Of course we do. Now, let's repeat the process a near infinite number of times. What do we have? Something much less intelligent being an observer that we didn't initially want to be one. The same argument applies if we start from a human also. We have to define some threshold of intelligence, therefore. But this is hideously arbitrary and not the kind of pattern that we want to see in nature or in our scientific theories. The term observer is difficult to define, and does not, therefore, lend itself to inclusion in a well defined theory of physics. See my post on quantum observers for further complaints.

  16. Totally different from the humaniora terms by Per+Abrahamsen · · Score: 4, Insightful

    It is important to notice that the light cones for all humans being (dead, living, and in all probability those not yet born), are not just ovrlapping, they are for all practical purposes identical, because we all live so close together (cosmologically speaking) in both time and space.

    There is a sad tendency of some less honrable people at humaniora to try to tie their pet models of the weak (consensus reality, social consructionism, cultural relativism, whatever it is called this month) to physical theories like quantum physics and even Einsteins relativity theory, apparently to give them some extra credibility.

    Apart from it being bad science to apply models outside their domain, these attempt are never really based on more than some shared terms, even if this usually is hidden by a flood of words.

    The models humaniora are actually pretty good in their own domain, as long as one remember they are models useful for dealing with a limited range of problems, and does not attempt to interpret them as metaphysical truths.

  17. Background for LQG and spin networks by HalfFlat · · Score: 5, Informative

    John Baez is a well-known mathematician/math. physicist who works in, among other things, quantum gravity. He is also very well known for the Usenet column This week's finds in mathematical physics, which is certainly worth a look a t if you're at all interested in these things and have a bit of a mathematics background.

    One of the great things about TWFiMP is the writing style: when reading it, one really does get the idea that one understands what's going on. Of course this tends to wear off soon after leaving the computer, but. At any rate, many of the TWFiMP talk about spin networks and quantum gravity, including for example week 43 and week 55. Week 110 talks specificially about Penrose's spin networks. He mentions some of Markopoulou's work in week 99, week 114 and week 133. These might provide a bit of a middle-ground between the very fluffy SciAm article and the hard stuff on arXiv.

    Of course there is also Markopoulou's recent expository article, which is a great introduction!

    1. Re:Background for LQG and spin networks by smaughster · · Score: 4, Insightful

      The abstract of the "hard stuff" mentions: "We show that all of these issues can be addressed by the recent application of the Kreimer Hopf algebra for quantum field theory renormalization to non-perturbative statistical physics."

      Great! We are talking about heavy duty physics, and this line says that all the stuff can be translated to a mathematical algebra, the one about rooted trees to be exact. I could teach nearly anyone what this algebra is in 5 minutes, how for example differentiation in n dimensions is reduced to a simple excercise with graphs (i.e. dots and lines) and concrete physical results can be proven by proving their counterpart in this simple algebra.

      Amazing how such a relatively new, seemingly unrelated part of mathematics (Hopf algebra's were put into new perspective in 1963 because virtually the same algebra can be used for approximation methodes like the Runge Kutta method) rapidly ganis such a central place in physics.

      --
      I intend to live forever, so far so good.
  18. Good story. by 1s44c · · Score: 5, Interesting

    I'd like to see more stories like this on slashdot. It would be nice if we could spend more time contemplating real science and less time bashing microsoft.

    I for one spend to much time being bitter at microsoft and not enough doing interesting things.

  19. Agreed, with some extensions and clarifications... by NanoProf · · Score: 5, Insightful

    The EPR 'paradox' isn't a problem at the level of physics. Quantum theory (even non-relativistic) makes very clear predictions about the statistical properties of measurements on spatially separated but correlated particles, and experiments agree. There is no violation of causality. No information propagates faster than the speed of light. Certainly the effect is weird, and it conflicts with some of our naive (i.e. non-quantum) intuitions of how to interpret a physical theory, but there is no logical contradiction and no need to extend or modify the quantum theory to account for experiment.

    Wavefunction 'collapse' has some interesting details to be worked out, and some deep matters of interpretation that could use clarification, but it also to date presents no conflicts between experimental results and theoretical predictions. Wavefunctions follow the time-dependent Schrodinger equation, always. It's just when the quantum mechanics extends substantially into macroscopic systems with very large numbers of degrees of freedom, the dynamics of the many-body correlated wavefunction becomes quite complex and our regular intuitions can't keep up very well.

    One thing to keep in mind is that wavefunctions do not exist, according to a reasonable definition of exist. The only thing that exists is that which can be measured, that which is physically observable, that which is accessible to an experimental observation. A wavefunction is not physically observable. It is a mathematical tool used to make predictions about experimental results. The simultaneity of collapse of a wavefunction isn't like the simultaneous collapse of say an egg carton. All physical properties related to the process of collapse of an egg carton can be measured by experiment as a function of distance across the carton: density, shear forces, stresses, shape, etc. Not so for a wavefunction.

    --
    Curtains for windows?
  20. Re:right, testing is the real challenge by packeteer · · Score: 4, Insightful

    Each dimension does not have to have the common names we give it but it helps to use those names. Using the same pattern you can give names to any of the other dimensions required by String Theory. You could use any type of measurement to explain it. You could explain it as a "hue" dimension. It does not have to be this but let me explain how this works.

    When you have a two dimension world you plot on the x and y axis'. When you add a third dimensions you can have infinite points using in space using the same x and y coordinates.

    When you add time to the third dimension it does nto change the thrid dimension at all. Two things can exist in the same place (a big no-no in physics) only if they do so in a different time.

    If you want to use soem type of "hue" explaination for the fifth dimension it would work like this. You have your regular 4 dimensional world we live in, then you add one more. Now each point in time is defined by x, y, z, time, and "hue". You can have infinite space inside the same old 4 dimensions. If you never changed the "hue" rating of your existance it would be like living on a two dimension sheet in a three dimensional world.

    Who knows if we really live in 4 dimensions? Im not saying we dont but there are some ways to explain why we would not have seen extra dimensions if we didn't live with em... but alas the turkey is almost done so i gotta go ;)

    happy thanksgiving

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