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Science

Relativity Finally Meets Quantum Theory? 449

Posted by chrisd from the yahoo-seriously-cool dept.
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."
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Relativity Finally Meets Quantum Theory? More

Relativity Finally Meets Quantum Theory?

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  • stereotypes? (Score:3, Funny)

    by newsdee ( 629448 ) on Thursday November 28, 2002 @04:26AM (#4773746) Homepage Journal
    She talks about physics like it's cooking. 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. If it turns out she's not, then, it's just a flash in the pan. Insert moronic sexist joke here. (I hope she's right though, it's about time that somebody found something significant, to finally have another woman's name in physics books).

    • Re:stereotypes? (Score:3, Informative)

      by El Pollo Loco ( 562236 )
      I don't really think it's supposed to be a sterotype. It's simply a comparison. The average person would consider cooking to be easier then quantum physics. Although judging by the fact that I have burned cereal, this might be wrong.

      • Stereotype are appropriate (Score:4, Insightful)

        by bfinuc ( 162950 ) on Thursday November 28, 2002 @05:25AM (#4773965) Homepage Journal
        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.

    • Re: Noether , Mitner (Score:4, Interesting)

      by guybarr ( 447727 ) on Thursday November 28, 2002 @05:34AM (#4774009)

      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)

  • The real challenge... (Score:4, Interesting)

    by Da Fokka ( 94074 ) on Thursday November 28, 2002 @04:26AM (#4773748) Homepage
    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.

    • Re:The real challenge... (Score:4, Interesting)

      by packeteer ( 566398 ) <packeteer@@@subdimension...com> on Thursday November 28, 2002 @04:33AM (#4773784)
      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.

      • Loop Quantum Gravity (Score:5, Informative)

        by anandrajan ( 86137 ) on Thursday November 28, 2002 @05:40AM (#4774027) Homepage
        Some of the players in loop quantum gravity (LQG) before Kalamara are Abhay Ashtekar [psu.edu], Lee Smolin, Carlo Rovelli, John Baez and Chris Isham [qgravity.org]. Also, Julian Barbour [platonia.com] has written a cute semi-popular book called The End of Time [amazon.com] on the subject as has Lee Smolin---Three Roads to Quantum Gravity [amazon.com]
      • IMHO, perhaps they are both correct, and it all depends on how you look at it/what you are looking for

        IANAP == I am not a physicist

      • That's because it is just a competing theory, which at this point has no predictions going for it. A scientific theory is only valid if it can make a testable prediction, and then that prediction has to be right; string theory is as of yet just a thought experiment, with no emprical data to back it up. Therefore, string theory in any form is not accepted.

        To recap; string theory looks neat, but doesn't (as yet) say ANYTHING about the real world. Your contention that it makes more sence of the real world is therefore incorrect.
    • The guy I most often hear is "the best physicist round" these days is Ed Witten, who doesn't seem to be too great on that front.
      The best guy since Einstein was supposedly Richard Feynman, who was supposedly terrific at explaining things to the layman. So much so, his papers were often criticised because of their use of common English. Quite a few physicists were apparently annoyed when Hawking got called 'Einstein's successor' or somesuch, since there were alot of people of his quality, and some beyond.
      Pity how the Universe itself is apparently just another political game..

    • Re:The real challenge... (Score:5, Funny)

      by Tharsis ( 7591 ) on Thursday November 28, 2002 @05:21AM (#4773955)
      Wow.. you must be really smart to be calling Stephen Hawkings a layman ;)

    • Re:The real challenge... (Score:4, Funny)

      by Dark Lord Seth ( 584963 ) on Thursday November 28, 2002 @05:41AM (#4774028) Journal

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

    • 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.

      Five years ago, Joe Sixpack couldn't install Linux and didn't have a clue about the universe's mysteries.

      My how times have changed.
    • I've read much of Stephen Hawking's work, and while he may be very smart, I really don't think he is a particularly good at explaining concepts to the layman.

      I find John Gribbin [amazon.com] and Paul Davies [amazon.co.uk] to be much better.

      If you enjoy this stuff, I would heartily suggest:

      John Gribbin, "In Search of Schrodinger's Cat" - great intro to quantum mechanics. The sequel is also very good.
      Paul Davies, "God and the New Physics " and "The Mind of God" - more general, thought-provoking discussion of science and the world.

    • Stephen Hawking (Score:5, Funny)

      by spakka ( 606417 ) on Thursday November 28, 2002 @06:06AM (#4774099)
      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.

      • The only Daleks I know are described as follows: Encased in their pepperpot-shaped travel machines, each Dalek is a mutant monstrosity from the planet Skaro. They are one of the Galaxy's most fearsome races, with no thoughts other than that of conquest. The Daleks consider themselves the most superior race in the Universe. Humanity and all of the other species in the Galaxy may be permitted to live as their slaves - but that which they cannot subjugate they will destroy. Their main weaponry is the gun attached to the front of their casings. Even a glancing shot is sufficient to despatch the hapless victim in screaming agony... I doubt the Stephen Hawking invented those....

  • Clarification... (Score:5, Informative)

    by grahamlee ( 522375 ) <graham.iamleeg@com> on Thursday November 28, 2002 @04:28AM (#4773757) Homepage Journal
    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?

    • Re:Clarification... (Score:2, Interesting)

      by Capybara ( 70415 )
      Yes, and it's disappointing that the article doesn't mention what her theory has to do with gravity, but just talks about the relativity bits.

      • Re:Clarification... (Score:2, Informative)

        by Xilman ( 191715 )
        Yes, and it's disappointing that the article doesn't mention what her theory has to do with gravity, but just talks about the relativity bits.

        Gravity is relativity. That is, general relativity is Einstein's theory of gravity.

        Paul

        • Re:Clarification... (Score:4, Informative)

          by grahamlee ( 522375 ) <graham.iamleeg@com> on Thursday November 28, 2002 @05:48AM (#4774050) Homepage Journal
          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 :-)

    • Re:Clarification... (Score:4, Informative)

      by guybarr ( 447727 ) on Thursday November 28, 2002 @06:14AM (#4774122)

      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.)

      • Re:Clarification... (Score:2, Insightful)

        by grahamlee ( 522375 )
        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.
        Perhaps Copenhagen is wrong?
        Then again, the wavefunction isn't a physical observable, but its modulus is. However, as with experiments on entanglement or teleportation, even though spooky action happens at a distance, the measurements still have to be made in such a way that information travel is subluminal. So maybe the wavefunction does instantaneously collapse, but as it is impossible to gain any information directly from the wavefunction relativity is preserved.

      • Agreed, with some extensions and clarifications... (Score:5, Insightful)

        by NanoProf ( 245372 ) on Thursday November 28, 2002 @09:01AM (#4774625)
        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.

  • Not Martha Stewart (Score:3, Insightful)

    by teece ( 159752 ) on Thursday November 28, 2002 @04:35AM (#4773786) Homepage
    Am I the only one that found some of the article's tone, and the cooking analogies, a bit sexist? I don't think the oven stuff at the end would have made it into the article if this work was being done by a man.

    As a student of physics, this is still a bit beyond me, but I'll be there soon. Things like this pop up occasionally -- most disappear. The theory has to make predictions that can be tested and verified. Just getting QM and gravity together mathematically is not enough.

    Tim
    • I don't think the oven stuff at the end would have made it into the article if this work was being done by a man.

      Would it have if the article had been written by a man? (This claimer; Amanda may be a man's name in New York, but it ain't in these here parts of the world)

      Or did you just assume that women can't write articles for SciAm?

      • (This claimer; Amanda may be a man's name in New York, but it ain't in these here parts of the world)

        Isn't that one of Bart's prank calls in The Simpsons? "I'm looking for Amanda Hugandkiss"?

    • Am I the only one that found some of the article's tone, and the cooking analogies, a bit sexist?

      The physicist and the author are both women. So, basically, your position is that women should be free to express themselves and act however they wish, just so long as it is not stereotypically feminine, because you say so. Gosh, what an enlightened attitude. Perhaps we should strap electrodes to them and zap them until they are rid of all these objectionable behaviours.
    • Am I the only one that found some of the article's tone, and the cooking analogies, a bit sexist? I don't think the oven stuff at the end would have made it into the article if this work was being done by a man.

      First, the article was written by a woman--perhaps that's where the 'chick stuff' came from. On closer reading, there is also evidence to suggest that the promising young physicist herself introduced the cooking analogies, which were only extended by the journalist. Remember, SciAm is targetting a popular audience (smarter than PopSci, but still). Articles like this will always try to make the person and his or her work seem more human. Scientific American ran a review of a biography of mathematician Paul Erdos a few years ago. The article emphasized his personal eccentricities and some funny anecdotes from his life--should we take SciAm to task for presenting a stereotypical view of the socially inept and out-of-touch mathematician?

      Lastly, why the hell is cooking still considered women's work by the sexism police on Slashdot? I'm male and I make my living from physics, but I'm also a pretty good chef. Among my friends, the best cooks are 1) a database designer, 2) a nanomaterials chemist, and 3) a molecular biologist. Two are female, one male. I'll let the guy know he shouldn't be doing that girly stuff, but I'm sure going to miss his creme brulee.

  • this sort of thinking has its uses and indeed is in use everyday. However, won't a lot of it be pre-empted when cold fusion comes out from underground? After all, Mitsubishi heavy industries, among others, is doing cold fusion right now, thanks to the politicization of research in the US.

  • Don't know about her theory but... (Score:3, Insightful)

    by jki ( 624756 ) on Thursday November 28, 2002 @04:37AM (#4773795) Homepage
    But based on her attitude, she might actually succeed in it.

    "Having fun is essential, because otherwise you get stressed out. You think, I have to show the universe is made out of atoms, and aaaaahhh, you flip out! So you want to keep loose."

    ...howevery, I feel like I need to upgrade my bird-brains every time when I read sentences like this:

    One experiment could be to track gamma-ray photons from billions of light-years away. If spacetime is in fact discrete, then individual photons should travel at slightly different speeds, depending on their wavelength

    • "If spacetime is in fact discrete, then individual photons should travel at slightly different speeds, depending on their wavelength"

      Through a vacuum or would these differences be noticable through mediums (read "air") as well? And, if so, would there be any interesting side-effects for the nature of Cherenkov radiation?
      • Off the top of my head I'd say the distance photons travell through air is way too short to see any effect...you'd need huge distances to find any effect, and those kinds of distances only occur through the interstallar medium...where there's dramaticcally little 'air' to be found.

  • Cooking? (Score:3, Insightful)

    by imevil ( 260579 ) on Thursday November 28, 2002 @04:43AM (#4773815)
    From the article:

    She talks about physics like it's cooking. (at the beginning), and In the meantime, she's hard at work, and waiting for the oven bell. (at the end).

    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?

    • Re:Cooking? (Score:4, Insightful)

      by Ripplet ( 591094 ) on Thursday November 28, 2002 @05:06AM (#4773894)
      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?
    • Well, I dunno. Perhaps you should ask the woman who wrote the article.

    • Re:Cooking? (Score:5, Insightful)

      by Citizen of Earth ( 569446 ) on Thursday November 28, 2002 @06:13AM (#4774117)
      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.

  • What's cooking (Score:2, Informative)

    by Cheese Cracker ( 615402 )
    I hope that her findings can be proven to be true, just so that she doesn't have to join Jan Hendrik Schön [physicsweb.org], Martin Fleischmann and Stanley Pons [ucsd.edu] in the hall of shame.

    • Re:What's cooking (Score:3, Interesting)

      by jihema ( 558787 )
      I hope so too, but being published in Scientific American first is not really a good sign.

    • Re:What's cooking (Score:5, Insightful)

      by guybarr ( 447727 ) on Thursday November 28, 2002 @05:57AM (#4774069)
      I hope that her findings can be proven to be true, just so that she doesn't have to join Jan Hendrik Schön [physicsweb.org], Martin Fleischmann and Stanley Pons [ucsd.edu] in the hall of shame

      This post points to a serious lack of understanding:

      The hall of shame is not for scientists who were wrong,
      it is for con artists cheating the scientific world

      most of the scientists are usually wrong. One cannot do
      real research w/o being wrong occasionally.

      Schon was a cheat and a liar and I hope he rots on some
      deserted island somewhere.
      F&P announced results they knew they could not be sure of to the general public, which just doesn't have the right tools to test them.
      They were not just wrong, they were deceitful.

      AFAIK this woman does NOT claim she united GR and QFT. She sais
      she has made a theoretical improvement which still needs to be tested.

      Even if she turns out wrong, she is very far from the
      halls of shame. Quite the opposite.

  • Physisist? (Score:5, Funny)

    by varjag ( 415848 ) on Thursday November 28, 2002 @04:48AM (#4773828)
    Physisist Fotini Markopoulou Kalamara (try saying that 3 times fast)...

    Try saying "physicist" once, and slowly.

  • Not to troll... (Score:4, Insightful)

    by brsmith4 ( 567390 ) <brsmith4&gmail,com> on Thursday November 28, 2002 @04:51AM (#4773835)
    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.
    • Get out to the west coast, San Diego is nice this time of year, and you will see some of the hottest girls you've ever dreamt about, in lab coats....

      That said my girlfriend is a grad student at UCI but she's working on her teaching credentials, while working as a model for the car show circuit and pretending to be Barbie(TM) for Mattel at Toys 'R Us... she is a good Catholic girl though so I won't disparage her reputation with any more details.

    • Re:Not to troll... (Score:3, Interesting)

      by stud9920 ( 236753 )
      What about this one [vub.ac.be] ? It may not be miss universe anymore, it may not be the easiest person to live/work with (I work in another department of the same university and we actively hate anyone from her department), but she is a very fine physics professor.

  • Metaphysical physics.... (Score:4, Interesting)

    by foniksonik ( 573572 ) on Thursday November 28, 2002 @04:56AM (#4773849) Homepage Journal
    "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.

    • Frankly, it seems to me that once you throw in quantum physics you get the "metaphysical POV" or "individual interpretations of the universe" one way or another. The idea that observation affects (note affects, not -effects-) reality is a fundamentally philosophical point, regardless of its verity, which is one of the things that makes quantum physics so fascinating.

      I'd like to point out that I am -not- disagreeing with the previous post.

      • Well not exactly... yes quantum physics inherently presents some of these issues but I'm referring more specifically to the 'observer' point of contention. Many will argue that form a non-specific and non intelligent/mechanical POV quantum physics implies multiple outcomes based on probability.

        What they don't argue is that the 'observer' ie: an intelligent and 'human-concious' entity can have a dirct impact on the outcome by 'perceiving' the activity. Age old question: "if a tree falls but no one hears it, did it make a sound?" or Schroedinger's Cat, etc....

        So the question I propose from her statements is: "Do we as observers, with our overlapping light cones (event horizons?), create our universe from a multitude of potentials?"

      • After re-reading your comment it sounds like I'm just rephrasing it for myself.... cool.

    • Totally different from the humaniora terms (Score:4, Insightful)

      by Per Abrahamsen ( 1397 ) on Thursday November 28, 2002 @06:42AM (#4774187) Homepage
      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.

  • Quantum observers (Score:4, Informative)

    by sunnytzu ( 629976 ) on Thursday November 28, 2002 @04:57AM (#4773857)
    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.

    • Re:Quantum observers (Score:2, Insightful)

      by Anonymous Coward
      The measurement problem was solved by Spinoza hundreds of years ago. God is observing the universe. Funny how science gets around to proving what religion has known for hundreds of years.

    • Re:Quantum observers (Score:2, Interesting)

      by sunnytzu ( 629976 )
      Although you may feel that the measurement problem is solved by God observing the universe, that gives difficulties for the EPR paradox. If God is observing the universe, then every conceivable quantum quantity has a definite value, surely? But this is impossible, as there are numerous quantities that are not co-measurable. You could then argue that God is outside the rules of quantum mechanics, and hence can perceive what He damn well likes, but then you can't use Him within a quantum theory as an observer, as He is not observing in an acceptable manner to quantum mechanics.

    • Re:Quantum observers (Score:2, Insightful)

      by pclinger ( 114364 )
      "I may still be a plain old physics student"

      Enough said. Ms. Kalamara here has a Ph.D in Quantum Gravity. I think she knows more on the subject more than a plan old physics student.

  • Uhm, maybe I'm being silly, but... (Score:3, Informative)

    by trveler ( 214816 ) on Thursday November 28, 2002 @04:59AM (#4773864)
    There's one thing I don't get. Here's the relevant snippet:

    But a spin network represents the entire universe, and that creates a big problem. According to the standard interpretation of quantum mechanics, things remain in a limbo of probability until an observer perceives them. But no lonely observer can find himself beyond the bounds of the universe staring back. How, then, can the universe exist? "That's a whole sticky thing," Markopoulou Kalamara says. "Who looks at the universe?" For her, the answer is: we do. The universe contains its own observers on the inside, represented as nodes in the network. Her idea is that to paint the big picture, you don't need one painter; many will do. Specifically, she realized that the same light cones she had used to bring causal structure into quantum spacetime could concretely define each observer's perspective.

    Because the speed of light is finite, you can see only a limited slice of the universe. Your position in spacetime is unique, so your slice is slightly different from everyone else's. Although there is no external observer who has access to all the information out there, we can still construct a meaningful portrait of the universe based on the partial information we each receive. 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.

    So my boggle is this: Until the first "observer" evolved, nothing observed the universe, so it existed in all quantum states simultaneously. If so, how did that first observer ever evolve? Or is she posutlating that the universe's existence is its own observation?
    • Hence my comment on Metaphysical Physics....

    • Re:Uhm, maybe I'm being silly, but... (Score:5, Interesting)

      by sunnytzu ( 629976 ) on Thursday November 28, 2002 @06:27AM (#4774150)
      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.
    • "so it existed in all quantum states simultaneously"

      I'd say that the current universe then evolved out of that quantum state in which an observer evolved out of a quantum state! Any other universe would be irrelevent, as this is the one we're in :)
  • From the article: "... gazing upward and knowing that there are countless stars we cannot see because not enough time has passed since the birth of the universe for their light to shine our way; they are beyond our light cone."

    This would seem to indicate that if we looked out far enough into space, we would see nothing. We've yet to find any boundary. When will we? When I was about 10 years old... I remember reading on the side of my McDonalds Happy Meal box that we'd see the "edge" of the universe within the decade. Why haven't we found it yet?

    --
    • "I remember reading on the side of my McDonalds Happy Meal box that we'd see the "edge" of the universe within the decade."

      That's the first article I've seen quoted from The McDonalds Happy Meal box. Odd, since it is truly the most reliable scientific resource of our time.

    • Re:Light cones and the edge of the universe (Score:2, Informative)

      by Anonymous Coward
      I remember reading on the side of my McDonalds Happy Meal box that we'd see the "edge" of the universe within the decade. Why haven't we found it yet?
      We have. The COBE satellite looked at light remaining from the Big Bang. It was a perfect black-body spectrum at around 2.7 Kelvin. There were small irregularities in the temperature distribution; the first sign of the formation of galaxies. That was what we expected, so that was cool.
  • According to the standard interpretation of quantum mechanics, things remain in a limbo of probability until an observer perceives them. But no lonely observer can find himself beyond the bounds of the universe staring back. How, then, can the universe exist?

    So, either we're just probably reading Slashdot or there is a God. Pick one.

  • http://arxiv.org/abs/gr-qc/0203036 [arxiv.org] for those of you that have advanced degrees in physics... could the rest of us have a translation? Of course I could be off with the publication, but it is hers and it's the only one Perimeter Institute had for her, and the introduction implies gravity with quantum physics... just a disclaimer. I don't have that advanced physics degree yet.
    • Wrong pal. The correct article is http://ru.arxiv.org/abs/gr-qc/0210086. However the article you refer is directly related to this one. But all that cooking journalistic dumbiness in SA is related to this more recent stuff.

      On the problem of observers. People don't get wrong with it. Note that the girl talks about two of the biggest problems of Physics - the relative observer that has to consider the restraints of his position and dynamics in the Universe, and the quantic observer that cannot make a deterministic prediction of all the physical conditions of one observation. Add these two things into one and try to guess what will happen to the observer.

      And note that they are about Quantic, nearly aka the atomic world. And that the talk goes about abstract observers, not real ones, located at that level. Thanks God we are in a bigger dimension that overlaps all the crazynesses of the underworld...

  • now what ? (Score:2, Insightful)

    by katalyst ( 618126 )
    Well.. we had relativity (which has been beyond us mortals), we had quantum mechanics ( whic again has been beyond us mortals) and now we have quantum relativity (and guess what ! they all are STILL beyond us). Now what? Humans have this notion that they are gonna solve the mystery of life.. which they may someday.. but not for the next few centuries (unless we have vulcans landing up on earth a-la star trek). When we discovered the atom we thought we had all the answers.. and NOW we say if we crack quantum mechanics.. we are gonna have it all. Hm.. maybe if I understoof what this lady was saying, it would help.. but.... wooooooshh.. over my head

    • Re:now what ? (Score:3, Insightful)

      by Queuetue ( 156269 )
      The mysteries of life (as we know them) are all but solved - most of them are simply unexploited due to moral or political pressure. Most of biology is understood, at least when viewed from a safe distance.

      This nice lady is working on the mysteries of the universe - specifically a unifying theory to merge quantum mechanics and relativity. Once someone does this, you'll find the mysteries of the universe might just start cracking themselves pretty quickly.

      Now, you may not have taken the time to understand relativity nor quantum mechanics, but I assure you that with the proper teachers, and effort on your behalf, neither is beyond the grasp of "mere mortals."

      It's a little silly of you to place a date (of a " few centuries") on a process you have yourself stated you don't understand. These nuts are crackable, with current technology and knowledge - no Vulcans required. Most of what's slowing us down is funding and interest, not mortality.
  • Everyone who's whining about the line "she talks about physics like it's cooking," should shut their pie holes. The reason that line is in there is not because the writer is sexist, it's because she DOES talk about physics like it's cooking ("to take this ingredient and another one there and stick something together").

  • The REAL articles... (Score:5, Informative)

    by doru ( 541245 ) on Thursday November 28, 2002 @05:30AM (#4773988) Homepage
    ...can be found in the arXiv database. A search [arxiv.org] 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...

  • Wolfram? (Score:2, Interesting)

    by SashaM ( 520334 )

    From the article:

    Each spin network resembles a snapshot, a frozen moment in the universe. Off paper, the spin networks evolve and change based on simple mathematical rules and become bigger and more complex, eventually developing into the large-scale space we inhabit.

    Is it just me or does this look a lot like what Wolfram suggested in "A new kind of science"?

  • Perhaps related... (Score:4, Interesting)

    by Naerbnic ( 123002 ) on Thursday November 28, 2002 @05:30AM (#4773991)
    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?

  • Physics is Art? (Score:2, Insightful)

    by Anik315 ( 585913 )
    It bugs me when these physicists get all postmodern about their work and call it art. What they do is organize phenomenalogical data into commessurable patterns. They then mess around with seemingly conflicting patterns in weird combinations to see if they can get 'fundamental' patterns. They do this over and over again. She probably means that advancing physics requires a willingness to break the rules, think differently, color outside the lines... etc. The the degree to which physics posesses that quality pales in comparison to the classical definition of art I suppose the process of physics does require creativity, but physics is an overwhelmingly destructive context for ideas.

    • Re:Physics is Art? (Score:3, Insightful)

      by infolib ( 618234 )
      She probably means that advancing physics requires a willingness to break the rules, think differently, color outside the lines... etc. The the degree to which physics posesses that quality pales in comparison to the classical definition of art.

      On the contrary, you have to be even better at "thinking differently" because your new ideas need to be both creative and in line with experiment. It is a form of art that allows creations rivalling the beauty of Michelangelos "David" (Maxwells equations etc.) but the constraints are so much stricter than those of marble.

      • Re:Physics is Art? (Score:3, Informative)

        by smaughster ( 227985 )
        Especially if certain very fundamental basic patterns arise at the strangest places. Take the algebra of rooted trees, a mathematical object dealing with special graphs. In 1963, is was shown that they relate to numerical approximation methodes. In 1998/1999 they were shown to relate to feynman graphs (high energy physics). In 2002 we see them in Fontini's work.

        That such an elementary math object appears in such different places certainly is something amazing. Realizing that your field of work had such a structure really requires more "intuition/feeling" then purely analytic skills. Art isn't far away.

  • P.R. for LQG (Score:2, Insightful)

    by levell ( 538346 )
    Really, this is just PR for L.Q.G, not that I'm knocking that - string theory attempts to solve similar problems (quantum gravity) and although it is in a much more advanced state of understanding (hundreds if not thousands of physicists have been working on it for 20 odd years) it is still completely hypothetical without a shred of experimental evidence and yet, if you listen to the popular science guys, that's quite often put in the small print - giving the impression that string theory is accepted fact. Giving some popular airtime to some of it's (admittedly few) rivals can only be a good thing.
  • But the Sci Am article is uninformed enough to sy she did something as fundamental as join Quantum Theory with Relativity (solve the puzzle of the past 80 years) and is too stereotyped towards women to focus on the subject matter.
    Dont get me wrong, I know personally of her achieements, I will be going to Waterloo U and have talked to the profs there. The speak highly of her. But this article suggests she did what Einstein/Bohr/Schrodinger couldn't do and beat up all the string theorists; without giving details how.
  • "According to the standard interpretation of quantum mechanics, things remain in a limbo of probability until an observer perceives them. But no lonely observer can find himself beyond the bounds of the universe staring back. How, then, can the universe exist?"

    I have always wondered about physicists declaring that things exists "in a limbo of probability" until they are perceived by an observer (the Schroedinger's Cat thing). My question is

    So how do physicists define "observer" and "being perceived"?

    Who qualifies as an observer? Humans? Cats? Light-sensitive amoebae? "Being perceived" in its most basic form would be: to cause a change in the state of another object. Is there any one knowledgable out there who can define the term "observer" as it applies to quantum physics?

  • Background for LQG and spin networks (Score:5, Informative)

    by HalfFlat ( 121672 ) on Thursday November 28, 2002 @07:13AM (#4774278)

    John Baez [ucr.edu] 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 [ucr.edu], 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 [ucr.edu] and week 55 [ucr.edu]. Week 110 [ucr.edu] talks specificially about Penrose's spin networks. He mentions some of Markopoulou's work in week 99 [ucr.edu], week 114 [ucr.edu] and week 133 [ucr.edu]. These might provide a bit of a middle-ground between the very fluffy SciAm article and the hard stuff [arxiv.org] on arXiv [arxiv.org].

    Of course there is also Markopoulou's recent expository article [arxiv.org], which is a great introduction!

    • Re:Background for LQG and spin networks (Score:4, Insightful)

      by smaughster ( 227985 ) on Thursday November 28, 2002 @08:25AM (#4774493)
      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.

  • Good story. (Score:5, Interesting)

    by 1s44c ( 552956 ) on Thursday November 28, 2002 @07:35AM (#4774342)
    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.

  • Speaking of Loop Quantum Gravity... (Score:3, Funny)

    by Larne ( 9283 ) on Thursday November 28, 2002 @11:46AM (#4775472)
    Just last night John Baez [ucr.edu] (mentioned several other times in this thread) announced [google.com] a potentially important breakthrough: a LQG calculation that derives the same value for a fundamental parameter as one based on classical assumptions. He calls it "tooth-gnashingly nerve-wracking exciting."

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