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Do you think physics departments should give equal time to LQG and string theory?

  1. Apr 20, 2008 #1
    Do you think physics departments should give equal time to LQG and string theory?

    Currently, the top physics research departments at the best Universities, from Princeton to Harvard to Stanford to Rutgers all employ string theorists in various capacities.

    When I say equal time, I am talking about offering phD positions leading to full professorships and tenure tract, to those with LQG phDs, doing LQG research.

    AFAIK, only Penn State has a LQG group, with private professors like Pullin and Baez doing research at other schools. From what I understand, phD's in LQG usually have to go to Europe or South America to find employment in LQG.

    Perhaps it should not be a 1:1 ration of string theorists to LQG but 1:2 or 1:3 ratio of tenure tract positions available to string theorists to LQG-candidates
  2. jcsd
  3. Apr 20, 2008 #2
    So you're saying that Princeton should hire three LQG guys for every string theorist?


    Why is this a physics question?
  4. Apr 20, 2008 #3
    I should say 1 position LQG to 2-3 positions for string, related in terms of the current debate over string theory (NEW, TWOP)
  5. Apr 20, 2008 #4


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    It does not make sense to split up things this way. what about astrophysics? Condensed matter physics? Biophysics? Optics? Nanophysics?
    You don't build a department by saying "ok, we will assign a number of positions per field according to some preassigned ratio". How would you determine those ratios anyway?
    It makes more sense to focus on some specific strengths and hire people working in closely related areas so they can talk to one another and collaborate, hire postdocs that will work with all the members of the group, etc.

    And this is not a physics question so I would say that it does not belong to this forum...but a lot of people here love to discuss the sociology of physics instead of actually talking about physics so I think the thread will be welcome.

  6. Apr 20, 2008 #5
    I think there should be a separate section in PF for sociology issues.

    But in any case, concerning the question posted here, there exists *the* problem of formulating a theory of quantum gravity. Period. It's a very hard problem. If the department is interested in people working on this problem, great. It doesn't matter the approach. What matters is the profile of the researcher. He(she) must be ready to embrace this research with an open mind, have an excellent technical capacity and know to ask the right questions. The theory of quantum gravity might perfectly end up to be something different from the present formulations which string theory or LQG are based.

    What is needed is a group of great minds, like those in the beginning of the last century. The death of JA Wheeler somewhat closed that era.
  7. Apr 20, 2008 #6
    What about research into Aethers?

    I think that many here would agree.
  8. Apr 20, 2008 #7


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    String theory is much broader than quantum gravity perse and is the reason for its success and why there are so many high energy theorists involved.

    If it had nothing to say about QCD/condensed matter or effective field theories/ supersymmetry you wouldn't see nearly as many people working in it.

    Keep in mind quantum gravity was a very small field in the 60s and 70s. You had a couple old tenured proffessors who worked on it here and there, but by and large it was considered the same way that quantum measurement theory is today. Read: A dead end for productive research for the immense majority of physicists.

    So yes, pure quantum gravity research doesn't deserve a lot of funding, b/c frankly it has very little experimental hope of being falsified anytime soon, and it is of vanishing relevance to the real world that we can measure atm. Chances are for a university, you will get way more bang for your buck, by funding a bunch of condensed matter physicists or nowdays astrophysicists.
  9. Apr 20, 2008 #8
    Well bang for the buck is always been interesting to me, why do Universities like Princeton have any string theorists, when condense matter physicists would give Princeton more bang for the buck? And if they do want to employ physicist in speculative, perhaps non-falsifiable scientific research (i.e string theory) why not some diversity (i.e twistor, LQG, non-commutative geometry, etc)

    I picked strings v.s loops given that
    1- major universities have major string theory research groups, hiring and awarding phd's, Penn state is the only LQG'ers I know of.
    2- According to string theory skeptics, string theory is inherently unpredictive, and not science

    As for LQG, what about loop quantum cosmology?
  10. Apr 21, 2008 #9


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    Huh? Like I said, string theory gives you mechanisms to learn about all sorts of things that are NOT quantum gravity. ADS/CFT for instance is applicable to condensed matter physics, cosmology, field theory, hadronic physics and is interesting mathematically. You don't get that with your random run of the mill quantum gravity theory (say done on a computer).

    The majority of particle physics phenomenology in the past twenty years is dominated by stringy inspired stuff (Large extra dimensions, twistor methods, brane dynamics, large N SU(N), Quiver guage theory, dualities, dimensional reduction, supersymmetry, holography, etc etc).

    All these ideas are pure money for a research department, and completely worth it. Whether the productivity remains that way in the future remains to be seen and is debatable, but for now it has largely payed its expense and then some (regardless of whether or not it turns out to be valid or not as a quantum gravity theory)
    Last edited: Apr 21, 2008
  11. Apr 21, 2008 #10
    Little Higgs
    Randal-Sundrum Models
    ADD gravity
    G2 MSSM from M Theory (http://arxiv.org/abs/0801.0478)
  12. Apr 21, 2008 #11

    Except that the theory has various errors. Personally, I'm really liking Deformed Special Relativity as a good starting point for a compeltely new theory of everything.
  13. Apr 21, 2008 #12


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    So what?:rofl:
    It will take 20 years before we can get any new technological benefit.
    I can only come up with two; clean up of radioactive waste and an improved approach to fusion
  14. Apr 21, 2008 #13
    Sometimes fundamental physics doesn't have practical applications.

    We are currently performing experiments to either credit or discredit Deformed Special Relativity. That makes it science.

    If you're looking for practical applications, go to an engineering forum. I just want a ToE for the reason of a further pursuit of knowledge.
  15. Apr 21, 2008 #14


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    Did I touch a nerve???
    Reality is knocking at the door.
    The gov./army rep. is asking for a payment of money or time.
    I will have to join the others in the country to do back breaking labor of getting the land ready for this seasons crop.
    The food riots are getting worst and governments are going to collapse before a solution is found.
    I'll have to do my thinking with a shovel in my hand. :rolleyes:
  16. Apr 21, 2008 #15

    I'm not a super huge fan of the theory being discussed by you and GearsofWar, but even I know well enough that it has predicted a set of unknown particles. To say that the theory's "errors" completely invalidate its predictions is the kind of religious fervour that has no place in science.

    It's fine and well to not spend one's time trying to learn a theory that might turn out wrong, but that's one's own personal choice. To think that one somehow has the right to make that choice for the remaining 6 billion or so people would be just plain silly. This behaviour reminds me of so many popular "crackpot"/"respectability"/"holiness" checklists... all of which naturally make me sick to my stomach.

    The communication and distillation of diverse ideas is the backbone of civilization. To go against that is not just "touching a nerve".
    Last edited: Apr 21, 2008
  17. Apr 21, 2008 #16
    Well, if it has LEE SMOLIN'S stamp of approval, then sign me up!

    And (please correct me if I'm wrong) I don't think Lisi actually quantizes gravity in his paper, although I could be wrong. He just showed in his paper how to embed the Lorentz group into E8 (I don't understand the math, nor the subsequent objections raised about it on the internet).

    So in that sense, Lisi's work isn't Quantum Gravity at all.
  18. Apr 21, 2008 #17
    Smolin also said that his quote was taken out of context, and that he probably should have chosen his words more carefully. Also, when asked directly which parts of the theory still stand, he simply referred to the action given in his own follow-up paper. The only reason I asked this of Smolin was because it was annoying to see person after person claim that Smolin was a "fool" because of the way Distler kept "correcting" him in regard to group theory. Try not to tell too much of a one-sided story, ok?

    For the record, I'm neither a crackpot nor a string theorist, so it seems like your hypothesis is dead in the water. Perhaps you and jal are more alike than you'd care to admit.
    Last edited: Apr 21, 2008
  19. Apr 21, 2008 #18
    I trade my claim for diplomacy for an insight what that famous LHC test I keep on hearing about (in internet forums) is, i.e. the appearant BSM physics, its detector signal, the implications if the signal is seen and possibly even an estimate of the time it takes to get the necessary statistical accuracy. The five papers citing Lisi's paper did -judging from the title- not seem to contain that information.
  20. Apr 21, 2008 #19


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    This thread is called Do you think physics departments should give equal time to LQG and string theory?

    You have not read my blog or you would not say that.
    This thread was diverted to the discussion of the merits of D8. (GearsofWar )
    I was, and still am reminding those who have forgotten that only in a society of surpluses can you practice your “thinking craft”.
    Therefore, the question of how a physic department spends money is secondary to the question of where the money comes from.
    In the end there are many problems that need to be addressed so that a portion of society can have the luxury of spending all of their time “thinking”.
    The world is changing ….
    I’m out of any further discussion in this thread.
  21. Apr 21, 2008 #20

    I shall read your blog, and will most certainly take back my words if I am incorrect. My apologies in advance.

    I agree with your perspective about being able to set time aside to think. It might seem like a socialist utopia, but I agree that those who can think should be given the freedom to do just that.
    Last edited: Apr 21, 2008
  22. Apr 21, 2008 #21
    So... I think LQG should get more attention than it does and I think that it would be a good thing if physics depts. would make an effort to ensure they have at least some people working on string theory alternatives on staff.

    But "equal time" is just silly at so many levels. For one thing this should not be viewed as a choice between LQG or String. LQG looks pretty promising from my (nonprofessional) viewpoint but it's hardly that if String is false then LQG is true. There are other approaches that are neither LQG nor String and there's not much more or less reason to expect any of them could be true. For another thing, there just aren't that many people who know LQG. There are lots of people who know string theory. If you want to hire equal numbers you're going to find this very difficult... "Equal time" just isn't a very good way to approach the problem.
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