Weinberg in Physics Today

The March issue of Physics Today is now available. It contains a piece by Steven Weinberg based on a banquet talk he gave to a group of postdocs. He describes his own memories of his time as a postdoc, writing that “Many of us were worried about how difficult it seemed to make progress in the state that physics was in then.” This was the heyday of S-matrix theory and he comments:

Some people thought that the path to understanding the strong interactions led through the study of the analytic structure of scattering amplitudes as functions of several kinematic variables. That approach really depressed me because I knew that I could never understand the theory of more than one complex variable. So I was pretty worried about how I could do research working in this mess.

He describes envying the previous generation of 10-15 years before his time, that of Feynman, Schwinger, Dyson, and Tomonaga, thinking that all they had had to do was sort out QED, and speculates that they in turn had envied the generation before them since quantum mechanics was even easier. I can see that he’s trying to provide encouragement, ending with

So the moral of my tale is not to despair at the formidable difficulties that you face in getting started in today’s research… You’ll have a hard time, but you’ll do OK.

Postdocs in high energy physics these days do need some encouragement, but I also think they need some recognition from their elders that they’re facing a different situation than that faced by earlier generations. Coming into a field that has not seen significant progress in about 30 years is a different experience than what Weinberg or previous generations of particle physicists had to deal with. High energy physics is now facing some very serious problems, of a different nature than those of the past, and I think these deserve to be mentioned.

In the same issue, Weinberg makes another appearance, in an exchange of letters with Friedrich Hehl about the torsion tensor in GR. Hehl takes him to task for his comments in a previous letter that torsion is “just a tensor”, pointing out that it can be thought of as a translation component of the curvature. Weinberg responds that he still doesn’t see the point of this:

Sorry, I still don’t get it. Is there any physical principle, such as a principle of invariance, that would require the Christoffel symbol to be accompanied by some specific additional tensor? Or that would forbid it? And if there is such a principle, does it have any other testable consequences?

Actually, Weinberg is rather well-known for taking the point of view that GR is just about tensors, and that their geometrical interpretation is pretty irrelevant, so it’s not surprising that he doesn’t see a point to Hehl’s comment. In his well-known and influential book on GR, he explicitly tries to avoid using geometrical motivation, seeing this as historically important, but not fundamental. To him it is certain physical principles, like the principle of equivalence, that are fundamental, not geometry. There’s a famous passage at the beginning of the book that goes:

However, I believe that the geometrical approach has driven a wedge between general relativity and the theory of elementary particles. As long as it could be hoped, as Einstein did hope, that matter would eventually be understood in geometrical terms, it made sense to give Riemannian geometry a primary role in describing the theory of gravitation. But now the passage of time has taught us not to expect that the strong, weak and electromagnetic interactions can be understood in geometrical terms, and too great and emphasis on geometry can only obscure the deep connections between gravitation and the rest of physics.

This was written in 1972, just a few years before geometry really became influential in particle physics, first through the geometry of gauge fields, later through geometry of extra dimensions and string theory. I recall seeing a Usenet discussion of whether Weinberg had ever “retracted” these statements about particle physics and geometry. Here’s an extract from something written by Paul Ginsparg, who claims:

back to big steve w., when he wrote the gravitation book he was presumably just trying to get his own personal handle on it all by replacing any geometrical intuition with mechanial manipulation of tensor indices. but by the early 80’s he had effectively renounced this viewpoint in his work on kaluza-klein theories (i was there, and discussed all the harmonic analysis with him, so this isn’t conjecture…), one can look up his research papers from that period to see the change in viewpoint.

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43 Responses to Weinberg in Physics Today

  1. Sean Carroll says:

    Weinberg’s point that the torsion is “just a tensor” is an attempt to draw a distinction with the Christoffel part of the connection, which is not a tensor. You can’t just stick a term like (connection)^2 into the action, but there’s no trouble at all sticking in a term like (torsion)^2, or any of a million other terms. There aren’t any symmetries that give you any information at all about what the dynamics of the torsion should be, or how it should couple to other fields. So you can write down whatever action you like. (In particular, there’s no obstacle to giving the torsion a mass at the Planck scale.) Consequently, there is no conceivable way that you could detect some new field and say “aha, that must be the torsion.”

  2. Peter Woit says:

    Sean,

    Isn’t this just like the curvature then?

    Won’t your particles couple to it in a very specific way, since you’re not changing the Dirac equation, just allowing spin-connections that are not torsion-free? I assume that’s the kind of physical prediction that Hehl is talking about.

  3. Tony Smith says:

    Peter said that Paul Ginsparg said “… by the early 80’s … big steve w. [Weinberg] had effectively renounced this viewpoint [of]… replacing any geometrical intuition with mechanial manipulation of tensor indices …”.

    I think that Paul Ginsparg is correct about that. At the 1984 APS DPF Santa Fe meeting, Weinberg gave a talk “Unification Through Higher Dimensions” in which he not only discussed “The Kaluza-Klein Idea” but also concluded by discussing “Research Directions” including “The SO(32), N+4=10 Green-Schwarz theory”.

    At that same meeting John Schwarz gave a talk (on work with Shahram Hamidi) entitled “A Unique Unified Theory That Could Be Finite And Realistic”, in which he discussed “SO(32) and E8xE8 superstrings” with respect to finding “the correct low-energy (compared to the Planck mass) theory in four dimensions with which to make contact”.
    Swarz went on to say that “In collaboration with J. Patera, we have classified all the chiral N=1 theories that satisfy the one-loop (and hence two-loop) finiteness conditions. The list includes theories based on E6, SO(10), SU(5), and SU(6) that can describe three or more families without mirror partners. However, if we also require the occurrence of elementary Higgs fields in representatins that can give realistic symmetry-breaking patterns, then one unique scheme is singled out. …
    The unique model that is potentially finite and realistic is based on the gauge group SU(5). …
    To be perfectly honest, we are not sure how seriously this should all be taken. The three-loop calculation could result in a dramatic failure and is therefore of utmost importance.
    The connection between superstring compactification and finite four-dimensional theories is only a speculation … It need not be true in general.”.

    IIRC, during the talk by Schwarz, Weinberg stook in the rear door of the lecture room. Many of the physicists at the meeting were on the edge in deciding whether or not superstring theory would be the new fashion for theoretical physics, and were looking to Weinberg for a sign about which way to go. At the end of the talk, Weinberg commented that he was favorably impressed, and in my opinion that comment had some influence in the establishment of superstring theory as the fashion and paradigm for the next 20+ years.

    It is interesting that in his 1984 Santa Fe talk Schwarz presented, on grounds related to what I think of as “real physics”, a “unique unifed theory”
    and
    that Schwarz proposed a direct test of that “unique” theory by doing three-loop calculations
    and
    that even though the “unique” theory failed to be a realistic model, superstring theory advocates refused to acknowledge the failure,
    and even now, over two decades later,
    they continue to “work” on stuff that has
    more and more complex structure (to avoid theoretical failure)
    and
    less and less contact with experimental observations (to avoid refutation by experiment).

    Tony Smith

  4. Weinberg is also famous for his non-orthodox views on QFT. For example, he writes on page 200 of his “The quantum theory of fields” vol. 1:

    Traditionally in quantum field theory one begins with such [Klein-Gordon] field equations, or with the Lagrangian from which they are derived, and then uses them to derive the expansion of the fields in terms of one-particle annihilation and creation operators. In the approach followed here, we start with the particles, and derive the fields according to the dictates of Lorentz invariance, with the field equations arising almost incidentally as a byproduct of this construction.

    To me this suggests that Weinberg does not consider fields as being fundamental physical quantities. However in another place (http://www.arxiv.org/hep-th/9702027) he seems to be contradicting himself:

    In its mature form, the idea of quantum field theory is that quantum fields are the basic ingredients of the universe, and particles are just bundles of energy and momentum of the fields.

    It is also interesting to see the evolution of Weinberg’s views on the local gauge invariance principle. On page 990 of Phys. Rev. 138B (1965), 988 he writes (after short introduction to what he calls “extended gauge invariance”)

    The only criticism I can offer to this textbook approach is that no one would ever have dreamed of extended gauge invariance if he did not already know Maxwell’s theory.

    I read it as an admission that he doesn’t know how to justify the gauge invariance principle, except by the fact that it works. I find this attitude somewhat refreshing when compared to the modern textbook dogmatic approach. He continues:

    In particular, extended gauge invariance has found no application to the strong or weak interactions, though attempts have not been lacking.

    This was in 1965. Long before electroweak theory and QCD. Do we know better today why there should be local gauge invariance? Besides the fact that it works.

  5. JC says:

    Tony,

    Has anyone done this particular three-loop calculation mentioned by Schwarz?

  6. Moshe says:

    The way I read the torsion issue is that it is an irreducible representation of the Lorentz group (= a tensor), so when coupling to gravity or anything else you just write the most general couplings consistent with symmetries, since there is no symmetry that will prevent them from being generated.
    \
    On the other hand, treating this tensor like “torsion” entails presumably very specific way of coupling to matter, in other words setting some of the possible couplings to zero.

  7. Sean Carroll says:

    No, particles don’t have to couple in any specific way. Ordinarily we decompose the covariant derivative into (d+G), where d is the partial derivative and G is the connection coefficients. And they have to come along with each other, since each alone is not a tensor. But with torsion this becomes (d+C+T), where C is the Christoffel part of the connection and T is the torsion. But there isn’t any reason they have to come together! (d+C) by itself is a perfectly good covariant derivative, and T is a perfectly good tensor. In a low-energy effective theory, we would expect T to couple to anything it was allowed by symmetries to couple to. And there aren’t really any symmetries to prevent it from being massive and coupling indiscriminately.

    More here: http://arxiv.org/abs/gr-qc/9403058

    Geometry is fun for inspiration, but physics plays by its own rules.

  8. gunpowder&noodles says:

    On the other hand, it is clear that the generic connection does have torsion. The restriction to zero torsion connections is a very strong one, so it should be justified. Setting something equal to zero is not the same as saying that it *has* to be zero for physical reasons.

    Traditionally, students were told that torsion had to vanish because non-zero torsion, being a tensor, would violate the equivalence “principle”. [Basically, anything about GR that one doesn’t understand is referred to that so-called principle.] People apparently didn’t notice that the same idea can be used to “prove” that the curvature tensor also has to be zero.

    Hehl had a very influential paper about torsion in Rev Mod Phys in about 1977. People interested in the subject should read that. Torsion certainly would be observable, but it hasn’t been: for some reason the torsion tensor of our Universe is zero. Nobody knows why.

  9. Tony Smith says:

    JC asked “… Has anyone done this particular three-loop calculation mentioned by Schwarz? …” [ for his “unique” string theory SU(5) “unified theory” ]

    Yes. As might be expected, after Schwarz made his 1984 Santa Fe talk, a lot of work was done on that SU(5) structure.

    For example,
    in Physics Letters B, Volume 160, Issues 4-5 , 10 October 1985, Pages 267-270,
    D. R. T. Jones and A. J. Parkes wrote a paper entitled “Search for a three-loop-finite chiral theory”. Its abstract stated:

    “Grand-unified theories have been constructed out of supersymmetric SU5 theories which are finite at one and two loops. We investigate the three-loop divergences in these models and find that they can never be three-loop finite. We present an example based on E6 of a three-loop-finite chiral theory.”

    The Jones-Parkes paper was received by Physics Letters on 19 June 1985, about 7 months after the Santa Fe meeting (which was from 31 October 1984 to 3 November 1984).

    Tony Smith

  10. Joseph Smidt says:

    I tend to agree with Weinberg. When I took GR I thought geometry was front and center in importance. Now taking QFT, I am beginning to think that geometry distracts from particles and fields and other fundamental quantum ideas.

    I also liked what Sean Carroll said in a comment on his blog. He said you should be careful wanting to axiomatize relativity. I’ve given this a lot of thought and it seems every time we axiomatize a theory we end up having to alter things here and there to fit nature. I’m beginning to think it is more important to have an evolving theory which evolves with experiment.

  11. Levi says:

    “That approach really depressed me because I knew that I could never understand the theory of more than one complex variable.”

    Sorry to isolate this bit of quotation from Weinberg, but it reminded me that I have never seen a good clear text on multi-variable complex analysis, Does anybody here know of one?

  12. Peter Woit says:

    Sean,

    You can certainly, as a consistent low energy theory, write down all sorts of things. But, if your Lagrangian is supposed to be a fundamental one, and your only fields are spinors and the spin-connection (metric, but not necessarily torsion-free), then there’s one simplest Dirac equation (standard covariant derivative, i.e. “minimal coupling”), and you can ask what the implications of assuming that are. I haven’t really looked at Hehl’s papers, but am just assuming that’s what he does. Forgetting questions of aesthetics, philosophy or whatever, Hehl claims to have predictions (even if not practically testable), and Weinberg seems to be saying he doesn’t see this (although his wording is unclear). Is Hehl right?

    I agree that the problem with torsion is that you don’t know what its dynamics is. If you start looking at all consistent possible couplings to all physical fields, maybe you can’t predict much of anything. Presumably Hehl is making some sort of assumptions about this dynamics.

    Joseph,

    The problem with the “GR involves geometry, QFT” doesn’t point of view is that the it turns out that the very particular QFT that governs the real world (the Standard Model) is very much a geometrical theory (gauge fields=connections, field strengths=curvature, matter fields=sections of associated vector bundles with connection).

    The point of talking about “axioms” is just so you make explicit what your assumptions are, and being clear about that is generally a good idea.

  13. Moshe says:

    Peter, interjecting again…GR certainly is not a fundamental theory, as it is not renormalizable.It is an effective field theory at low energies, so you can only make sense out of it if you allow all possible couplings (they run with scale, so it is meaningless to just set them to zero, zero at what scale?). So, if you add to your theory that particular tensor, there is no way to ensure it couples precisely like a torsion. If I got it right, that is the issue discussed.

  14. Sean Carroll says:

    I think Moshe and I are in agreement. Things like “simplicity” and “aesthetics” and “geometry” might inspire you to think about theories with certain symmetries and certain degrees of freedom. But once you have that, you should write down all of the possible terms consistent with the symmetries; if they’re not there in the fundamental Lagrangian (whatever that means), they’ll be generated at low energies by radiative corrections.

    There are many specific models with torsion, and each individual one may very well make predictions. But there is no possible observable that would allow you to conclude that a certain new degree of freedom was the torsion. It’s just a tensor, as someone once said.

    (In fact, classic “Riemann-Cartan theory” doesn’t even give the torsion a kinetic term, for the very bad reason that it’s not there in the Einstein-Hilbert action; since the Einstein-Hilbert action didn’t have torsion at all, that’s just silly. If you don’t give it a kinetic term, it’s just a Lagrange multiplier and you can integrate it out, leaving some non-renormalizable contact interactions.)

  15. Peter Orland says:

    Levi,

    There are few readable texts on several complex variables. I assume you mean subjects like polydiscs, Hartog’s theorem, envelopes of holomorphy, etc. The best known texts are by Bochner and Martin and by Vladimirov, but these are quite old and it isn’t clear how useful they are nowadays.

    A short book which is to the point is the paperback by Narsimhan. A more
    sophisticated text by is by Krantz.

  16. Peter Orland says:

    Sorry that’s Narasimhan.

  17. woit says:

    Moshe and Sean,

    I understand the effective field theory philosophy that our Lagrangians are just effective low energy theories, so all you have is what you think you know about the symmetries of the theory to constrain terms in the Lagrangian, and non-renormalizable terms like the Einstein-Hilbert one occur with powers of the energy scale at which the effective field theory is no longer valid.

    But I’m just not convinced by it. The fact that asymptotically free gauge theories make sense at all energy scales makes me suspect that they’re not just effective field theories for something more fundamental. I think it continues to be a valid thing to do to try and make sense of QFTs not just as effective low energy theories, but as fundamental theories, valid at all energy scales. If you try and do this, there are three sources of problems:

    1. Elementary scalars like the Higgs. They’re bad news for lots of reasons, and quite possibly are just effective fields, not part of the fundamental theory (e.g. technicolor). Maybe the LHC will clear this up…

    2. The U(1) gauge coupling. Maybe there are GUTs, and the U(1) unifies with a non-abelian group, is asymptotically free above a certain energy scale.

    3. GR. Maybe the people claiming N=8 supergravity is finite are right. Maybe there are fundamental Lagrangians that give consistent dynamics at all energies, with an Einstein-Hilbert term, other terms having some specific structure. There seems to be something going on in supergravity that we don’t understand, causing extra cancellations. Maybe the LQG people are right, and if you quantize your theory differently you’ll get something that makes sense. Maybe part of this story is that, just like SU(2) and SU(3) connections are fundamental fields in the non-gravitational part of the theory, the spin connection is a fundamental field, not necessarily torsion free, and its torsion components may have some well-defined dyamics, with measurable consequences.

    I’m still curious about Hehl’s claims of a prediction, and what assumptions they make. Any comments about those?

  18. Sean Carroll says:

    I’m happy to admit that there is some fundamental high-energy Lagrangian, but what we actually observe at low energies is the low-energy effective field theory. For example, the gauge field-strength tensor doesn’t involve the torsion at all, so there is no “fundamental” coupling between torsion and photons. But there is a coupling between torsion and fermions, and between fermions and photons, so voila — at low energies you get an effective coupling, suppressed by the Planck scale, between torsion and photons. And so on — there’s nothing in the dynamics of “torsion” that protects it from being just another propagating tensor field at low energies.

    I believe that Hehl is referring to classic Einstein-Cartan gravity, in which the torsion is non-propagating. You can integrate it out to leave a four-fermion interaction, suppressed by the Planck scale. Observable in principle, but not relevant to any conceivable experiment.

  19. Peter Woit says:

    Sean,

    OK, I think it’s clear now that you and I were just talking about two different things. I was discussing a conjecturally fundamental Lagrangian, you the effective low energy Lagrangian relevant to what we actually measure. In principle the low energy Lagrangian is derivable from a fundamental one, should it exist, but I certainly acknowledge there’s no problem-free candidate for such a thing at the moment.

  20. D R Lunsford says:

    I am so happy that Weinberg is still Weinberg!

    Yes, torsion in GR proper is a lost cause because of reducibility. But, you can make a theory where torsion is a sort of gauged electromagnetic duality, and there it is interesting. Since a charge-pole system has an intrinsic angular momentum independent of spin, and since asymmetry of the connection is associated with intrinsic angular momentum, torsion becomes very interesting. But I have other things to work on.

    The Weinberg book on GR is far and away the best one to be had, even now. The approach is thoroughly geometrical, in spite of the author’s own statements. See this thread on SPR.

    -drl

  21. JC says:

    Peter,

    Is there a possibility that there does not exist a “fundamental” Lagrangian?

    Or maybe higher energy physics (ie. higher than the electroweak scale) cannot be quantitatively described in a Lagrangian/path integral framework?

  22. D R Lunsford says:

    Sean Carroll said

    Consequently, there is no conceivable way that you could detect some new field and say “aha, that must be the torsion.”

    You could if you could find a magnetic monopole.

    -drl

  23. Peter Woit says:

    JC,

    By “Lagrangian” I was referring to the standard QFT setup, in your favorite formalism: path-integral, Hamiltonian, or whatever. Sure, at scales we haven’t probed yet, QFT may no longer describe things. Maybe it will need to be thrown out in favor of string theory or something else. But there’s no evidence for this, and, to me, the fact that asymptotically-free QFTs give mathematicallly beautiful theories that are highly constrained and perfectly consistent at all energy scales seems very striking. Maybe nature has got a better idea, and these are just low energy approximations, but I haven’t seen a convincing better idea.

  24. D R Lunsford says:

    JC,

    This is the approach of David Finkelstein as I understand it – if you are philosophically comfortable with that, then you should investigate his work.

    -drl

  25. Chris W. says:

    Can anyone clearly state the presuppositions behind the assumption that a “fundamental” Lagrangian exists? Is there a way to know that one doesn’t exist, or must we settle for simply observing that we haven’t found one—ie, all the candidates have problems—and their are some general reasons to be skeptical that we will find one?

  26. Moshe says:

    One more comment, possibly redundant…The use of EFT does not commit you to the form of the fundamental theory. Even when you have a complete description, such as in QCD, it is still useful to use various EFT (such as chiral PT, soft collinear EFT, etc.) in different regimes. That is why I don’t like the expression “EFT philosophy”. It is not a philosophy, it is just a self-consistent approximation scheme.

  27. D R Lunsford says:

    Chris,

    My own view is that the Lagrangian is the embodiment of the idea of a conservation law, and insofar as physics is the study of conservation laws, it involves a Lagrangian. Finkelstein believes instead that physics is about processes, and that conservation laws are derived ideas in the limit of many processes.

    -drl

  28. Peter Woit says:

    Chris W. and DRL,

    Sorry, but this discussion has moved far off-topic into a kind of discussion I don’t want to have to try and moderate here. Please stick to comments relevant to what Weinberg had to say in Physics Today.

  29. Levi says:

    Peter Orland,

    Thanks! I’ll take a look at those books.

  30. Tony Smith says:

    Levi asked “… Does anybody here know of … a good clear text on multi-variable complex analysis … ? …”.

    In addition to the references given by Peter Orland,
    from my old (1960s) college days, a book entitled “Analytic Functions of Several Complex Variables (Prentice-Hall 1965) by Gunning and Rossi is an introduction that I like.

    The Gunning-Rossi book is based on polydiscs, which are different from unit balls,
    so you might also want to look at the book “Function Theory in the Unit Ball of C^n” (Springer-Verlag 1980) by Walter Rudin. As Rudin said in his preface:
    “… Around 1970, an abrupt change occurred in the study of holomorphic functions of several complex variables. Sheaves vanished into the background, and attention was focussed on integral formulas and on the “hard analysis” problems that could be attacked with them … The ball is the prototype of two important classes of regions that have been studied in depth, namely the strictly pseudocomplex domains and the bounded symmetric ones. …”.

    If you are interested in the bounded symmetric domains, a standard reference is the book “Harmonic Analysis of Functions of Several Complex Variables in the Classical Domains” (AMS Translations of Mathematical Monographs Volume 6 1963) by L. K. Hua (whose life story in China is very interesting but probably off-topic here).

    Two recent books with a lot of interesting further details are:
    Analysis on Symmetric Cones (Oxford 1994) by Jacques Faraut and Adam Koranyi; and
    Analysis and Geometry on Complex Homogeneous Domains (Birkhauser 2000) by Jacques Faraut,Soji Kaneyuki, Adam Koranyi, Qi-keng Lu; and Guy Roos.

    Of course, the above is far from an exhaustive list, and you can find a lot more fascinating stuff to read if you are interested.

    Tony Smith

  31. Levi says:

    “The Gunning-Rossi book is based on polydiscs, which are different from unit balls”

    Right, and for various reasons I am more interested in the unit ball. Unfortunately, the book by Rudin is hard to get ahold of these days. Thanks for the help, though, and I know I’m off topic so I will leave it at that.

  32. nontrad says:

    I have to agree with Peter on his point about asymptotically free theories. QCD, for example, from it’s number of parameters to its mathematics and experimental verification is a very very interesting theory. To speak loosely, I’ve always regarded QCD as a paradigm.

    GR, on the other hand, (where I’ve spent more then a few idle moments) is, as much as everyone has ever wanted it to be anything other, a much much more difficult situation (including the work of….insert bigwig buzzword names here from A to Z).

    And here on this blog and elsewhere, we all know this! Bottom line, GR is a stumbling block that is not simply the speed bumb that the success of SU(2)XU(1) or the success of SU(3) might suggest. Instead, GR is more like an Everest of some kind… and like Everest just waiting for the right person (who as far as I am concerned will arrive one of these days).

    When I was first learning GR I read Weinberg’s book and considered his comments about geometry and, simply, I was confused. A primary source of my confusion was Chandra’s comments about how GR is ‘indistinguishable’ from a geometric view point. If the two are indistinguishable then why have a preference? Why not use the tool for the job that gets the job done? After all, who really cares? Afterall, this isn’t philosophy…this is physics borne out of a history that includes Bethe’s calculations…meaning always have a calculation!

    Well, it’s probably obvious that I have a dog in this fight…. and I suppose I do.

  33. Thomas Larsson says:

    IIRC, Schrödinger was very excited about torsion in the 1940s, thinking that it was a means to reconcile gravity with QM. Einstein, having thought about and dismissed torsion 25 years earlier, made him change his mind. There was a paper about this on the arxiv a number (5-7) of years ago.

  34. Benni says:

    Lubos has now a discussion on Weinberg vs Hehl.
    http://motls.blogspot.com/2007/03/steven-weinberg-vs-weird-physicists.html

    He calls The editor of “Annalen der Physik” and former chief of the workgroup “gravitational physics” in germany a “weird physicist” because Hehl’s theories would not come close to experiment….

    (german gravitational physics was rather good, because not completely devoted to fashions like strings. In Germany, traditionally many approaches are considered. I do not like it, when our (small) gravitational physics is malighed this way. Hehls theories are not more weird and disconnected from experiment than string theory is. People like Lubos would be called as ill-suited here because Lubos follows standard-fashion, not able to create own ideas.

    I do not know, If someone should bring this to attention of the professional association of gravitational physics in germany:
    http://www.zarm.uni-bremen.de/GR/organisation.htm
    maybe someone has the time to send an email to the responsible persons:
    http://www.zarm.uni-bremen.de/GR/kontakt.htm

  35. woit says:

    Benni,

    I don’t think people should be contacting the (large number) of targets of Lubos’s unprofessional behavior. If people see a problem with it, and don’t want to do what is generally considered to be the sensible thing (ignore him), it would make more sense to contact those of his colleagues who have promoted him, and now appear to tolerate if not encourage his behavior.

  36. Benni says:

    Yes. But this must be done by german gravitational physicists. That is, one must first inform the GRE group of the German DPG about Lubos, so that Ehlers, Hehl, Kiefer, Nicolai and Fraundiener can take the appropriate actions.

    The point is:
    German theoretical physics suffers since the second world war when Hitler had forbidden jewish physics and relativity.
    Due to the speculative nature and risky business of this research, government was and is very sceptical of it and would to this day not create any new professorships studying relativity. In Germany, there are (without the AEI) only around five relativity groups. And this groups are generally under the pressure of a majority of experimenters who think that they simply do not need this research which has no connections to any sort of experiments.

    So, it is very bad, if the small theory group in germany is maligned from someone outside.

    Since the only reason to install new theoretical professorships for german government would be the pressure, that germany will lose important competence to the US. (This is the reason why they agreed to fund some strin projects recently).

    If a Harvard Professor calls a german gravitational physicist as “weird” it could have consequences for the small group in Germany.

  37. woit says:

    Benni,

    I doubt that scientific policy decision-makers in the German government are reading Lubos’s blog, so presumably would be unaware of his nonsense about Hehl, unless you bring it their attention.

    If they are reading Lubos’s blog and taking it seriously, German science has a lot worse problems to worry about….

  38. Benni says:

    Of course, policy makers are not reading Lubos blog.

    But maybe experimentalists, who are curious about theoretical physics and want a good reason to set an experimentalist on the chair when Hehl becomes emeritus.

    Or other members of the Harvard group can read this, who are then, after some look at the publications of Hehl, finding out, how strange Germans theoretical physics is (not string theoretic).

    In fact, German policy makers often get their referees from foreign countries. In this situations, such entries of Lubos blog do not help when one wants to enlarge a research group.

  39. gunpowder&noodles says:

    Benni: don’t worry, LM will soon be leaving Harvard, because he is being persecuted by left-wing academics on the grounds that he thinks that GR is nothing but perturbation theory around Minkowski space. He also thinks that topologically non-trivial spacetimes are possible but they, too, are perturbations around Minkowski space, and this too is anathema among leftist academics. In short, LM’s 1920s style understanding of GR is politically unacceptable in Cambridge, so he has to leave and that will solve your problem.

  40. Benni says:

    Haha,
    Well, I know at least one Gravitational physics group in germany (the one of Dehnen in Konstanz) which was destroid because Dehnens chair was after his retirement not taken again.
    This chair was stopped because a majority of experimentalists (solid state physicists and optical physicists who thought that theoretical research on cosmology and general relativity is not worth doing.

    Well, and this here might have been a reason too:
    (I’ve wondered everytime who the referee of the Bogdanoff Hoax paper in class quant grav was. In his Math-Zentralblatt review of the Bogdanoff paper, it seems clearly that Heinz Dehnen did not get their joke:
    http://zmath.impa.br/cgi-bin/zmen/ZMATH/en/quick.html?first=1&maxdocs=3&type=pdf&rv=Heinz+Dehnen&format=complete

  41. Benni says:

    An interesting thing to note might be, that Hehl, whom Lubos calls a weird physicist has much more publications in prestigious journals than Lubos and even very much more citations!

    and well, it seems that Lubos fears consequences. He writes now on his blog (I wonder what this is about. In every case, the german GR association should be informed about Lubos):

    Lubos wrote:
    There’s just far too much organized influence terrorizing people in science. Whenever your results or conclusions of your work disagree with a sufficiently large group of ignorants, they will attack you personally in the worst possible ways. They will present the fact that your results reject their preconceptions as your moral flaw.

    I am looking forward to be away from the focus of these intellectual bottom-feeders who exist not only on Not Even Wrong and who enjoy a silent approval by many of the leftist officials in the Academia.

  42. Peter Woit says:

    Benni,

    Please, enough about Lubos. People who want to read his rantings can go to his blog. He generates a vast amount of this kind of stuff, devoting attention to it would overwhelm any sort of intelligent discussion. Enough.

  43. King Ray says:

    Peter, et al, thanks for posting on this topic. I found many of the links and comments very interesting.

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