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Relativity Finally Meets Quantum Theory?

Posted by chrisd on 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."

7 of 420 comments (clear)

  1. 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.
  2. 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.

  3. 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...

  4. 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
  5. 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!