Why No “New Einstein”?

Lee Smolin has a piece in the latest Physics Today entitled Why no “new Einstein”?. Unfortunately it’s only available to Physics Today subscribers, although Lee tells me he will see if he can put it on-line on his web-page. Tony Smith previously mentioned this in a comment to an earlier posting.

The problem Lee addresses seems to me to be an extremely important one. Pretty much every knowledgeable particle theorist that I talk to these days, string theorist and non-string theorist, agrees that current ideas about how to go beyond the standard model are not working very well. Everyone hopes that some big new idea will come along and show the way forward, with people often wistfully speaking about how maybe some bright post-doc out there may be at this very moment working on the needed new idea. The problem with this is that what is needed is probably something quite different than any of the current popular research programs, and finding it may be difficult enough to require someone’s concerted effort over quite a few years. If this is so, it’s very hard to see how anyone on the standard career path in the US is going to be able to do this. A young post-doc here generally only has a couple years in between needing to apply for new jobs, and if he or she were to devote those years to working hard on a very speculative new idea, this would most likely be suicidal for their career.

Some will argue that young theorists should just try and work on speculative ideas in their spare time, spending enough time working on currently fashionable topics such as string theory to impress people enough to ultimately get a permanent job, at which point they can work more seriously on their speculative idea. The problem with this is that getting up to speed and participating in the latest trendy research in string theory is a very demanding task, one that isn’t likely to leave much time or energy for other projects. In addition, it’s not at all clear that being willing to work hard on an obviously failed research program like string theory is consistent with having the intelligence and drive needed to do something really new. Instead of working on string theory, a young theorist could try and work on one of the other popular topics such as cosmology or phenomenology, but these are very different subjects than fundamental work in quantum field theory. A young theorist would be more likely to be able to find the necessary time if he or she went to work as a night-time security guard.

Lee makes several excellent proposals about how to restructure the way hiring is done to encourage young people who want to try something new. I hope he has some success in getting the powers-that-be to realize what a serious problem the field is facing and take some of the actions he suggests.

Two completely unrelated topics:

Lubos Motl has a posting about the Harvard Commencement, where it seems they’re giving Witten an honorary degree (Columbia already did this in 1996). He also writes about a new web-site for the Sidneyfest, the conference in Sidney Coleman’s honor that was discussed here and on many other weblogs. The new web-site includes copies of letters to Coleman from people who couldn’t attend the conference. In one of them Greg Moore recalls and reproduces Coleman’s proof from the late eighties that string theory is the unique theory of nature.

For something pretty weird, see this from the latest Notices of the AMS. There’s more about the activities of its author on Robert Helling’s weblog. The new issue of the Notices also contains an article about the 2006 NSF budget request for mathematics.

Update: Lubos Motl has his own comments on Smolin’s article, together with a link to some site where someone seems to have posted the article without attribution.

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86 Responses to Why No “New Einstein”?

  1. Peter says:

    Good idea, I’d been thinking of doing that.

    I have been deleting some comments, but am trying to err on the side of letting people say what the want to say.

  2. Anonymous says:

    Peter,

    Could you put the text of Lee Smolin’s reply letter in your next blog entry? It is buried
    here among the postings of loonies and
    it deserves to be more widely known (at
    least parts of it) as it helps to understand
    his position and motives better. If that is
    impossible, can you at least remove the
    two postings right after that letter that are
    stupid, offensive and simply indecent.

  3. Anonymous says:

    What’s wrong with anomalies? Sure, it turns first class constraints into second class constraints, but Dirac showed us how to deal with that.

  4. Juan R. says:

    Well, I agree with Ruadhan

    Now it is a usual popular claim that Witten is the new Einstein or even the new Newton.

    Sincerely, that is stupid. I’m sorry but Witten is not a 10% of a Feynman, regarding to physics.

    Dan said

    1- “there is no current experimental data that clearly goes beyond the SM and GR.” This is not true. There is experiments and data. SM was designed for typical accelerator physics experiments, if one continue to test it one probably fin nothing. Apply the SM to a molecule, for example, and after we will talk about that.

    Has you computed the total orbit of Mercury using full GR (including non radial components)? Orbit programs use only some GR effects in perihelion and light deflection but ignore time delays in the computation of orbit. Why?

    2- “theories that go beyond SM and GR such as ss/m-theory make predictions (10D-SUSY) that are not currently testable.” Incorrect again. Alternatives to GR are doing predictions about the future Gravity Prove B, alternatives to SM also can be verified in molecular experiments. There are proposals in literature for verifying the SM several orders of magnitude more exact that usual tests.

    3- “there is no experimental evidence to guide theory.” False again, there are dozens and dozens of current anomalies in data that guide to us to new theoretical frameworks. For example, certain anomalies in tomahawk data arise from new forces do not predicted by QED.

    In a recent Physical Review D:

    may reflect departures from both Newtonian gravity and GR on galactic and larger scales. Now alternatives to GR are traditionally required to possess an Newtonian limit for small velocities and potentials… also raises the possibility that the correct relativistic gravitational theory may be of a kind not considered hitherto.

    A “new” einstein will make predictions like the universe is not 10D and SUSY, I am practically sure.

    “same can be said for other approaches, such as LQG-volume and area operators.” This is false; the existence of a quantum of volume and area can be proved. In fact, it has been theoretically proven that no existence of quantum invalidates some well-known experimental data. I mean an indirect verification of the quantum not one direct test (at least i don’t know any), somewhat like curved spacetimes in GR are not directly measured but compatible with many data.

  5. dan says:

    I am not entirely certain how physics can benefit from a “new” einstein since the original einstein made specific predictions that were soon testable,einstein attempted to explain discrepiences with experimental results and known physics of his time, a new einstein would have the following problems

    1- there is no current experimental data that clearly goes beyond the SM and GR and

    2- theories that go beyond SM and GR such as ss/m-theory make predictions (10D-SUSY) that are not currently testable.

    3- there is no experimental evidence to guide theory.

    if a “new” einstein makes predictions like the universe is 10D and SUSY — there would be no way to confirm it.

    (same can be said for other approaches, such as LQG-volume and area operators).

    so i don’t entirely understand smolin’s point. maybe the “new” einstein is alive and publishing and his name is witten, but we don’t have the technology to test witten’s theories.

  6. Thomas Larsson says:

    Dear Lee,

    Let me emphasize that I am not a string theorist – on the contrary, over the last years I have had strong disagreements with Lubos and others, especially over the role of diff anomalies. While initially a statistical physicist, the success of CFT made me interested in Lie algebras, where I discovered how to generalize the Virasoro algebra beyond 1D and developed its representation theory, together with mathematicians like Moody, Rao, Berman and Billig. In particular, the Virasoro algebra in 4D is the anomalous form of the algebra of 4-diffeomorphisms, which is the constraint algebra of GR in covariant formulations (in non-covariant canonical quantization the constraint algebra is modified).

    So when I speak about diff anomalies, I do it as someone who has developed new mathematics which has not been absorbed by the physics community. You may wish to keep that in mind.

    As to the issue of anomalies, i.e. the claim that we ignore the established knowledge that “INFINITE-DIMENSIONAL CONSTRAINT ALGEBRAS generically acquire anomalies on the quantum level…” is simply false. It is contradicted by rigorous existence and uniqueness theorems in LQG.

    Whereas I claim that this is true, it is not at all generally accepted. On the contrary, it is widely asserted that there are no pure gravitational anomalies in 4D, see e.g. Weinberg’s QT of F II, ch 22. Nevertheless, the constraint algebra of GR contains many subalgebras isomorphic to the infinite conformal symmetry in 2D, generated by vector fields of the form f(z) d/dz, where e.g. z = x^0 + ix^1 or z = x^2 + ix^3. Upon Fock quantization, these conformal subalgebras will in general acquire anomalies for the usual reason, making the whole shebang anomalous.

    The reason why these anomalies cannot be seen in conventional field theory is that the relevant cocycles are functionals of the observer’s trajectory in spacetime. Unless this trajectory is introduced and quantized in conjunction with the fields, the relevant anomalies cannot be formulated. This is IMO the crucial obstruction to the quantization of gravity.

    1) The approach to quantization of constrained systems is different in string theory and LQG. The former approach depends on a gauge fixing that refers to a fixed background metric. It results in the construction of a Fock space. The latter is background independent and involves no background metric, no gauge fixing and results in a state space unitarily inequivalent to a Fock space.

    2) There is a body of rigorous results that support each kinds of quantization. Hence it cannot be a question of which is correct mathematically. Both are correct, within their contexts. It is a question only of which construction is appropriate for which theories and which describes nature.

    Conventional quantization has turned out to describe nature in other contexts. I think this is a good reason to believe that it is the correct approach. In particular, CFT has been successfully applied to 2D condensed matter, where conformal anomalies have been measured experimentally. This is of course a different context and not directly relevant, but this fact has shaped my basic instinct that anomalies are very real things which cannot depend on the quantization method used.

    3) The treatment of constraints in string theory depends on certain technical features of 1+1 dimensional theories, particularly the fact that there is a gauge in which L_0 plays the role of a Hamiltonian and therefore should, in that gauge, be quantized so as to have a positive spectrum. The anomalies are not generic, as asserted above, rather they depend on the additional condition that L_0 should be a positive operator.

    Yes, this is the crucial point. In any physical theory, there should be some positive operator which can be interpreted as a Hamiltonian; there is a physical requirement that energy be bounded from below. Of course, in GR there is a Hamiltonian constraint rather than a genuine Hamiltonian. This is another reason to introduce the observer’s trajectory; you can define a genuine Hamiltonian as the operator that translates the fields relative to the observer.

    Anyway, in all applications of Lie algebras to physics so far, the reps have been of lowest-weight type. At least for finite-dimensional Lie algebras, all unitary irreps are of this type.

    There are other reps of Diff(S^1 ) that are non-anomalous but in which L_0 is not positive.

    If you consider the restriction to the algebra of polynomial vector fields, generated by L_m with m >= -1, then all irreps have a vacuum vector (or are dual to such a rep).

    So a choice is made in the standard quantization of string theory, which his motivated by the physics. This does not mean it is the right choice for all physical theories.

    OK. I disagree.

    4) Conversely the existence and uniqueness theorems which support the LQG quantization work only in 2+1 dimensions and above for the reason that gauge fields don’t have local degrees of freedom in 1+1 dimensions. The existence theorems tell us that there are quantizations in 2+1 and higher of diffeo invariant gauge theories that have unitary, anomaly free realizations of diffeo invariance. The uniqueness theorem tells us that the resulting state space we use in LQG is unique.

    Contrary to string theorists, I claim that anomaly freedom is not a necessary requirement. To illustrate this point, let me again use the bosonic string as an example and quote from GSW, subsection 2.4: ‘Classical free string theory can be consistently formulated for any spacetime dimension, but quantization with a ghost-free spectrum requires D less than or equal to 26. […] In the special case of D=26 and a=1 the spectrum is entirely tranverse, with many decoupled zero-norm states.’

    Thus, D=26 is special, but D less than 26 is not ruled out by consistency requirements. It is only in 26D that it is possible to pass to the reduced Hilbert space by imposing the physical state condition L_m|phys)=0, but when D less than 26 this is not necessary, because the full, unreduced Hilbert space is already positive-definite.

    Thus, my position is that some diff and gauge anomalies are good, making it possible to break diff and gauge symmetry on the quantum level, such as the string in D less than 26 illustrates. This does not mean that all gauge anomalies are good, of course. On the contrary, I recently gave a simple algebraic argument why conventional gauge anomalies, due to chiral fermions and proportional to the third Casimir, indeed are inconsistent. This argument does not apply to observer-dependent anomalies, which are proportional to the second Casimir.

    The idea that diff and gauge anomalies may be consistent is of course very controversial.

    With regard to the non-standard quantization, in which holonomies, but not local field operators are well defined, it is of course true that when applied to standard systems this leads to inequivalent results. “This apparently leads to unphysical consequences, such as an unbounded spectrum for the harmonic oscillator.” But, give me a break, do you really think someone is proposing to replace the standard quantization of the harmonic oscillator with the alternative one? What is being proposed is that the quantization used in LQG is well suited to the quantization of diffeo invariant gauge theories.
    In case it is not obvious, let me emphasize that harmonic oscillators are not relevent here, and can play no role in a background independent quantum theory, precisely because the division of a field into harmonic modes requires a fixed background metric. Thus, the physics of the problem REQUIRES an alternative quantization.

    Sorry, but here I flatly disagree. I find it very disturbing that LQG methods yield the wrong result for the harmonic oscillator.

    I am frankly puzzled why someone who claims to know the literature well would throw up examples like the harmonic oscillator up in this context. I can try to understand their point of view, but it certainly reads as if they either are choosing to ignore the basic point, which is that background independent quantizations cannot use fock space, or they are looking to make debating points to impress ignorant outsiders.

    I agree that a diff invariant quantization of gravity cannot use Fock space, and I am convinced that such a quantization does not exist. However, a diff covariant Fock space quantization of gravity may very well exist. By this I mean a quantization in analogy with the string for D less than 26: the unreduced Hilbert space is consistent in itself, and diffeomorphisms are promoted to a genuine but anomalous symmetry acting on the full Hilbert space.

    A step in this direction was taken in hep-th/0504020. Sure, there are problems: the (manifestly covariant) regularization has not quite been removed, no invariant inner product has been found, and no hard predictions have been extracted. But there is a Hamiltonian which is bounded from below in the regularized theories, the analogous construction for the harmonic oscillator has a spectrum bounded from below (it is not quite right, and I discuss why), and infinities cancel best (though not quite, so I am doing something wrong) in 4D. Most importantly, since phase space variables are promoted to operators in the usual way, this is genuine quantization, which is witnessed by the presence of anomalies.

    Finally, I didn’t express myself very well on the sociological issues. I agree with you about the problems with string theory, and I did not mean that funding to LQG should be stopped. However, given what I feel is a major problem (the harmonic oscillator spectrum), and that LQG already is the second biggest player in QG, I cannot really think that it is badly underfunded at present levels.

  7. Anonymous says:

    Indeed, string theorists truely are legends in their own minds.

  8. Ruadhan says:

    Thomas Larsson said:
    >It would be very wrong to dismiss string theorists as misguided fools or corrupt villains. There might be exceptions, but many of them are among the smartest physicists on this planet.

    I smell moral pressure from string theorists on this issue. It is considered immoral to say that string theorists aren’t superhuman geniuses. Let me say this: I have met and talked to many of them, and they seem to me to be no more intelligent on average than a typical mathematician or theoretical physicist. Just as it is OK to exaggerate how bad Hitler or Saddam Hussein were, for example by saying that they ate babies, it is OK to exaggerate how clever string theorists are. A person who says that Saddam didn’t eat babies can be attacked for being a Saddam-sympathizer, and a person who dares to say that all of this “string theorists are all geniuses” talk is mere propaganda can be attacked for claiming to be more intelligent than string theorists, which nobody is entitled to do unless they know more than all the string theorists about heteroskedastic fibrations over David-Letterman manifolds.

    String theorists aren’t the smartest guys on the planet. They’re just enmeshed in a macho culture where they have to claim to be super-geniuses, and they can conceal their mediocrity behind a cloak of gibberish which one must become a string theorist to see through.

  9. Ruadhan says:

    Lee said:
    >Then, because of the possibility that quantum computers could break codes, there has been a lot of support for the last few years. And a lot of progress has been made, both experimentally and theoretically on aspects of foundations of QM.

    It seems to me that any progress that has been made has been in the realm of taking the previously existing understanding of QM and applying it to new systems. People have talked about qubits and Shor’s algorithm and quantum registers and have demonstrated quantum teleportation, but these are all straightforward applications of the previously known and well-understood formalism of quantum mechanics.
    I think that this is no more indicative of progress being made on the foundations of quantum mechanics than the successful factorization of a large number constitutes progress on the foundations of arithmetic.

    An example of a genuine non-trivial thing that
    quantum mechanics says is the following:
    Suppose there are N experiments with the
    following properties:
    1. Each experiment has only two possible results.
    2. If we perform the same experiment twice, then
    we get the same result.
    3. If we know in advance with certainty that a
    particular experiment will give a particular
    result, then the probabilities of the possible
    results for all other experiments are 50%.

    Then N is less than or equal to three.

    Nobody has ever attempted to address questions like why this should be true. Instead, it seems that the quantum computation people have agreed amongst themselves that they like the many-worlds interpretation and have left the foundations there.

  10. Anonymous says:

    gold

  11. Lee Smolin says:

    Dear Peter and colleagues,

    I am grateful for the attention given to my essay. I only want to emphasize a few points here. The main thing is that the essay is carefully written. It does not advocate more funds to LQG or any other program. It explicitly advocates more support and positions for young, ambitious theorists pursuing their own research programs who are unaffiliated with any larger program. Several proposals are made for how to accomplish this. I would hope that the focus of the discussion could be on these proposals.

    -String theory is criticized in the essay mainly because it is currently sociologically dominant, and so subject to the problems mentioned. It was necessary to do so as many readers of physics today will be unfortunately unaware that there are any problems with string theory, or any viable alternatives. Anyone with a long enough memory will know that the sociological issues in high energy theory predate string theory, and have hurt physics in the past, i.e. in the case of S-Matrix theory.

    -I hope I don’t have to say that I am not anti-string theory. My current last paper on the ArXiv is a technical paper in string theory, and I have 14 more in past years, plus 8 papers on related topics such as the landscape. I wouldn’t have written these papers if I didn’t think there was a good chance string theory is relevant to nature. The fact that someone like me who contributes sometimes, but not exclusively, to string theory, is not considered “a string theorist” is part of the sociological problems my essay criticizes. Similarly, the fact that one can elicit angry responses, and be called “anti-string” for carefully and correctly recounting the actual status of various conjectures is a sign of an unhealthy sociology. No one calls someone anti-LQG or anti-QCD when they do a similarly honest summary of what is known and not known in those fields.

    -I would claim that the sociological issues mentioned in the essay have hurt string theory even more than they have hurt the alternative programs, because they greatly limit the range of ideas worked on, and because people with a lot of imagination and intellectual independence are either selected out or choose themselves to work within communities which are more friendly to diversity and imagination. As a result, key issues such as the question of a background dependent formulation, or perturbative finiteness, don’t get a lot of attention, in spite of their centrality for the whole program.

    -I was grateful that someone noted the range of subjects at the LQG meetings. This was not planned, it is a natural outcome of the more open and curious atmosphere among people who work on the subject. We don’t believe we should have a meeting without inviting people from alternative and rival programs to report to us what they are doing, as well as to serve as critics. At the meeting in Marseille last May we even invited a persistent critic of LQG-Ted Jacobson-an early contributor who is now very critical of the subject-to give a talk to lay out his criticisms. I think it would be very good for string theory if the organizers of their meetings took a similar attitude.

    -Someone asked for a blanket term for LQG, CDT, causal sets etc. We use background independent approaches to quantum gravity. There is a lot of interchange of ideas, techniques and people among these programs, and many of us have contributed to more than one. There is a very different intellectual climate, in which diversity, creativity and independence are strongly encouraged.

    -Someone is asking for what is “LQG proper?” But the fact is that a lot of different things are now going on roughly under the name of or related to LQG. After all, this is now a community of > 100 people and there is no orthodoxy and no one trying to control what people work on. We agree generally on what has been achieved and what problems remain open, but not much beyond that. There is a healthy variety of approaches and attitudes towards the open problems. If there is one thing we all agree on it is that no approach is likely to achieve the right theory that is not background independent at its foundations. Come to the meeting and see what is happening.

    -While the point of my essay was not to advocate more funding to any particular direction, if you ask me I will of course say that I think that people working on background independent approaches to quantum gravity deserve much more support. Among them are Loll and Freidel, that I am glad someone mentioned, but there are many others.

    -I did not, as Lubos implies, advocate funding a large number of people who do nothing but think about the foundations of quantum theory. What I do advocate is much more support for the kind of person who might be inclined to work on foundational issues. These are deep and independent thinkers who believe that the road to progress in physics is confronting the hard problems directly. But there is no need to argue about whether more funding for foundations of quantum mechanics would be fruitful. The experiment has been done. For decades there was no support at all, and slow progress. Then, because of the possibility that quantum computers could break codes, there has been a lot of support for the last few years. And a lot of progress has been made, both experimentally and theoretically on aspects of foundations of QM.

    -Although this essay was not written to advocate LQG, since it is attacked in response I should try to clear some things up. Someone asks for an accounting of the present status of the field. I among others, have given one in hep-th/0408048, shortly to be updated.

    As to the issue of anomalies, i.e. the claim that we ignore the established knowledge that “INFINITE-DIMENSIONAL CONSTRAINT ALGEBRAS generically acquire anomalies on the quantum level…” is simply false. It is contradicted by rigorous existence and uniqueness theorems in LQG. As a few people do nevertheless take this seriously let me start from a point we can agree about and see if we can clear this up for good. I would hope we can all agree that:

    1) The approach to quantization of constrained systems is different in string theory and LQG. The former approach depends on a gauge fixing that refers to a fixed background metric. It results in the construction of a Fock space. The latter is background independent and involves no background metric, no gauge fixing and results in a state space unitarily inequivalent to a Fock space.

    2) There is a body of rigorous results that support each kinds of quantization. Hence it cannot be a question of which is correct mathematically. Both are correct, within their contexts. It is a question only of which construction is appropriate for which theories and which describes nature.

    3) The treatment of constraints in string theory depends on certain technical features of 1+1 dimensional theories, particularly the fact that there is a gauge in which L_0 plays the role of a Hamiltonian and therefore should, in that gauge, be quantized so as to have a positive spectrum. The anomalies are not generic, as asserted above, rather they depend on the additional condition that L_0 should be a positive operator. There are other reps of Diff(S^1 ) that are non-anomalous but in which L_0 is not positive. So a choice is made in the standard quantization of string theory, which his motivated by the physics. This does not mean it is the right choice for all physical theories.

    4) Conversely the existence and uniqueness theorems which support the LQG quantization work only in 2+1 dimensions and above for the reason that gauge fields don’t have local degrees of freedom in 1+1 dimensions. The existence theorems tell us that there are quantizations in 2+1 and higher of diffeo invariant gauge theories that have unitary, anomaly free realizations of diffeo invariance. The uniqueness theorem tells us that the resulting state space we use in LQG is unique.

    5) Now it is true that Starodubstev and Thiemann have found it an interesting exercise to apply the LQG techniques to free string theory. Not surprisingly they get a theory that is unitarily inequivalent to the usual one. This does not mean that the usual quantization of string theory is wrong, nor does it mean that the LQG techniques are wrong when applied to other problems, where the existence and uniqueness theorems together with a large number of results prove their worth. All we learn is that the two quantizations are inequivalent, which was to have been expected.

    6) With regard to the non-standard quantization, in which holonomies, but not local field operators are well defined, it is of course true that when applied to standard systems this leads to inequivalent results. “This apparently leads to unphysical consequences, such as an unbounded spectrum for the harmonic oscillator.” But, give me a break, do you really think someone is proposing to replace the standard quantization of the harmonic oscillator with the alternative one? What is being proposed is that the quantization used in LQG is well suited to the quantization of diffeo invariant gauge theories.

    In case it is not obvious, let me emphasize that harmonic oscillators are not relevent here, and can play no role in a background independent quantum theory, precisely because the division of a field into harmonic modes requires a fixed background metric. Thus, the physics of the problem REQUIRES an alternative quantization.

    The detailed motivation is, I think, well argued in the papers, and are supported by the results as well as the existence and uniqueness theorems. First, is well known that a complete coordinatization of the gauge invariant configuration space for a non-Abelian gauge theory requires the holonomies. Second, using them gives rise to the unitary non-anomolous reps of the spatial diffeomorphisms.

    Nor is anyone proposing using non-seperable Hilbert spaces for the full theory, the point is that when one mods out by the piecewise smooth spatial diffeos one is left with a seperable Hilbert space.

    I am frankly puzzled why someone who claims to know the literature well would throw up examples like the harmonic oscillator up in this context. I can try to understand their point of view, but it certainly reads as if they either are choosing to ignore the basic point, which is that background independent quantizations cannot use fock space, or they are looking to make debating points to impress ignorant outsiders. They must know comments like this are not going to influence experts, because they are, after all, taken from our own papers, written precisely because we wanted to clarify the difference between the new and standard quantizations and the limits of the applicability of each.

    With regard to the sociology of the string-loop division, “Roughly speaking, string theorists are fundamentally particle theorists with a strong understanding of quantum theory, whereas loop people are gravitists with a background in GR”, this is a myth. Rovelli, myself and many other people in LQG were trained as particle physicists, myself at Harvard in the late 70’s. Most of the physical motivation for LQG comes directly from ideas about formulating gauge theories in terms of loops that were studied by Polyakov, Wilson, Migdal, Mandelstam, Neilsen and others. LQG is squarely an outgrowth of their intellectual tradition. The only thing we added was to correctly treat the diffeomorphism invariance exactly in the quantum theory. This led to new results just as the exact treatment of gauge invariance in lattice gauge theory led to new results. I would claim that we made progress in LQG precisely because we had a very good grounding in QFT.

    String theory, as it is practiced, makes much more contact with the general relativity tradition, especially the once discredited tradition of extending general relativity to add dimensions and degrees of freedom in the search for a unified field theory. You are much more likely to read a paper which studies solutions to a generalizationsof the Einstein equations, with hbar=0, by a string theorist than by someone working on a background independent approach to quantum gravity.

    This of course does not mean that string theory is wrong. But I believe it does mean that by enforcing a narrowly restrictive notion of what constitutes good work, the community of string theorists has hampered progress in string theory by excluding from consideration the lessons learned by attempts to do what string theory must do eventually if it is to be a real theory: which is to find a background independent formulation of a quantum theory of spacetime.

  12. Curious says:

    Well said, M. I think that we have reached the
    common ground, and the discussion was
    useful. A revolution can start with a new Einstein —
    or with less imaginative new Plank and Bohr —
    or nonimaginative new Rutherford and Michelson. Eihter outcome is fine and useful
    to physics. What is needed is a large
    pool of technically savvy receptive people
    who can carry it out when it finally starts.
    Thanks to string theory we have this pool.
    You may not like the theory but it keeps
    able people busy and sharpens their skills;
    it is superb mental gymnastics and it will
    be useful in the end. Some diversification
    would not hurt, but in all probability people
    will end up exploring not one but several
    dead ends. They will also stop understanding
    each other completely, just like LQG and string people. Groupthink will not be breached; there will be more insular groups.
    But that’s nor here nor there.

    M is also right that the best way to bring the true revolution about is, yes, to revise
    the fundamental assumptions. My own prejudice which I share with Einstein is that GR is not the correct classical
    theory of gravitation (and that is why it is so
    difficult to quantize). Experimental verification
    of GR is still a work in progress; we can wait.
    It will all sort out in the end.

    Thank you, M, for your contribution to this discussion, and thank you, Peter, for bringing
    the subject up.

  13. mortain says:

    In addition to the traits listed below as contributing to Einstein’s success, wouldn’t it be pertinent to also add that he – like many other pioneers and lone wolves, such as Newton, Wiles and Perelman – had the time to pursue problems which interested him? Unlike Newton’s day and Einstein’s day, perhaps the only way to ensure that one has the time to work on (and eventually solve) outstanding, significant problems in any subject in our era is to make the time for oneself. Einstein may have had time to theorize at the patent office. Newton had free time forced upon him by an outbreak of bubonic plague. As Peter asserted, it may take seven years to solve a major academic problem – but this would surely require full-time work upon it. Wiles may be an exception, but then again he was aware of the problem he wanted to solve from a young age.

    Furthermore, I thought Einstein only graduated from the modern equivalent of a technical college with a diploma, and never went to anything approaching a graduate school.

  14. Quantoken says:

    Thomas Larson: “It would be very wrong to dismiss string theorists as misguided fools or corrupt villains. There might be exceptions, but many of them are among the smartest physicists on this planet”

    BUT the SMARTEST physicists CAN ALSO BE completely misguided fools. In another thread some one said: “…that it was pity the Creator had not taken advice”. The reason the Creator did not take advice was the pity fact that smart people like Edward Witten wasn’t born yet to give the Creator some advices how the universe should be created and how many dimentions it should have.

    Seriously, the nature is the way the nature is and you can not treak the nature to fit your theoretical model no matter how smart you could be. If the universe is not 10-D, Edward Witten can not turn it into 10-D no matter how hard he tried. The pity things is at the end of day it may very well turn out all wrong and Edward Witten’s would have wasted some of the most intelligent minds on this planet in vain.

    BTW, Einstein was never super smart or super intelligent. He was average in lots of aspects. But one thing that makes him great is he could think outside the confinement of the box, and he pick apart common ideas that other people took for granted, and find that these ideas were really not meant to be taken for granted, and he happened to be correct!

    Quantoken

  15. Anonymous says:

    … seem quite promising to me, e.g. dynamical triangulations. My comments referred to LQG proper. The papers I have looked at may be a few years old, but there has hardly been any changes in the fundaments since then.

    Posted by: Thomas Larsson at June 14, 2005 03:16 AM

    We obviously need better terminology, Thomas. Who is it that you are referring to when you say “LQG-people”? What current research to you mean when you say “more money to LQG”?

    However, the suggested cure, which more or less explicitly reads more money to LQG, is problematic since many people feel that the LQG people are ignoring well-established facts.

    Posted by: Thomas Larsson at June 12, 2005 06:13 AM

    Two places–Hermann Nicolai’s department at AEI and Smolin’s Perimeter Institute–are centers where there are a lot of LQG people. I am not sure there is anyone at either place doing what you would call “LQG proper”.

    Perhaps it would give some substance to your comments, so I could better tell what you mean, if you would name some persons at AEI or PI who have posted “LQG proper” work on arxiv in the past year.

    Since I hold you in high regard, I am quite curious to know what specific recent papers, say by AEI or PI people, you would pick to typify “LQG proper”. This would typify the kind of research for which Smolin’s essay, in your view, “more or less explicitly” advocates more funding.

  16. Thomas Larsson says:

    To the anonymous poster (Marcus?):

    I have not said that LQG should be deprived of money. However, it is the second best funded approach to quantum gravity, and it has recently been well advertised in the press.

    I think I have a reasonably good ideas what loop people are up to. There are several research programs present at Loops 2005, some of which seem quite promising to me, e.g. dynamical triangulations. My comments referred to LQG proper. The papers I have looked at may be a few years old, but there has hardly been any changes in the fundaments since then.

    After the Loops meets Strings conference at AEI Potsdam, several string theorists have examined LQG closely from their viewpoint, Nicolai et al. but also Helling-Policastro and spr comments by Urs Schreiber. Although there might be some Schadenfreude in these papers, I believe that the critique voiced therein is serious and seriously meant, and it should not be dismissed easily. In particular, the second paper compares conventional and LQG quantization. To quantize in the usual sense, we start from some phase space and replace the q’s and p’s by operators and Poisson brackets by commutators. However, the q’s and p’s do not exist as proper operators in LQG (not both of them anyway), but only in exponentiated form. This apparently leads to unphysical consequences, such as an unbounded spectrum for the harmonic oscillator.

    It would be very wrong to dismiss string theorists as misguided fools or corrupt villains. There might be exceptions, but many of them are among the smartest physicists on this planet (though I may have made some hasty comments sounding differently in the heat of debate). I have even found myself in agreement with Lubos Motl a lot recently (on physics, my opinions about politics are uninteresting). It is really only when he makes these weird statements about string theory, like it is immensely successful, predicts the standard model, and is already proven correct, that I disagree, and he has not made so many claims of that nature recently.

    Roughly speaking, string theorists are fundamentally particle theorists with a strong understanding of quantum theory, whereas loop people are gravitists with a background in GR. So when string theorists say that LQG is quantum theory only in a weak sense, I think one should listen.

    The importance of diffeomorphism group in GR is hardly in question, whether you call it general covariance, diff invariance or background independence. In fact, the lack of background independence is often used as an argument against string theory.

    Perhaps I am barking up the wrong tree, but at least I have found my own tree to bark at. In a time when genuinely new ideas are scarce, this is at least something.

  17. Anonymous says:

    M said:


    [2] the key problem is that we are making flawed assumptions about the form (or ingredients) of a more fundamental theory, in which case the failure is one of imagination or insight rather than effort.

    M, let’s look more closely at your second cause which you call “[2]” and consider the possibility that it is especially operative in the US. I will explain but first look at this example of a paper by someone at Lyon (FR) and two people at Cambridge (UK)

    http://arxiv.org/gr-qc/0506067

    For context, glance at the abstracts of the four papers Laurent Freidel has written this year.

    http://arxiv.org/find/grp_physics/1/au:+Freidel/0/1/0/all/0/1

    I would say that the scientific establishments that support this are able to take general relativity seriously and pursue, with some of their resources, the idea that one should FIRST get a quantum spacetime geometry, a background independent, nonperturbative quantum gravity, and then, when one has quantum spacetime dynamics on a continuum, which will be a mathematically new continuum, THEN one can build on that a new field theory and a new standard model. So the program is to get a RELATIVISTIC QUANTUM PHYSICS but not special relativistic like earlier quantum field theory, not merely built on Minkowski space, but the real thing: a GENERAL relativistic quantum physics built on a continuum with no prior commitment to some fixed geometry.

    For whatever reason that agenda seems to be understood by the establishments outside US and people like Freidel can work in Canada, Germany, France, UK.

    Let us suppose that a scientific establishment which only knows to go directly for the UNIFIED THEORY therefore SCREWS UP because it is incapable of supporting work like Freidel’s, because it only knows to try for a more fundamental theory in the way that STRING TRIED, on manifolds with a prior fixed metric, or on Minkowski space. We can entertain the idea that this kind of establishment screws up because of a flawed vision: because it DOES NOT TAKE SERIOUSLY the 1915 lesson of General Relativity of gravity as geometry. Because of this limited vision it is unable to support people like Laurent Freidel doing spin foam + matter, and people like Renate Loll doing CDT computer simulations of quantum universe. So Loll has to be at Utrecht (at Gerard ‘t Hooft’s institute) and Freidel has to be in Canada or France, and his co-authors have to be at Cambridge UK and Loll’s co-authors have to be at Copenhagen and Potsdam and Krakow Poland.

    BECAUSE THEY AND THEIR LIKE CANNOT WORK IN THE USA because the establishment people cannot imagine to quantize Gen Rel FIRST and get a quantum spacetime dynamics and THEN on that new continuum to build a unified theory—-a relativistic quantum physics.

    That is how I see your “cause [2]”. there is no mystery about good ideas, progress towards a more fundamental theory is going WELL at the moment, there have been surprising developments in the past couple of years. But the US is somewhat retarded about noticing and lacks the preparation to hop on the bus. So Smolin essay is pointing out not that he or his postdocs are unhappy (they can always go back to Europe or find jobs in Canada) He is pointing out to US academics that the US is falling behind in theoretical physics ( in quantum gravity and other branches that matter, not string theory)

    The reason Smolin would say to diversify the programs in US departments, and to tune the support system more towards resourceful mentally independent people is NOT so that the fundamental problems of physics will be solved (that view is a bit US-centered, if necessary they really can do without us, if the US stays stuck on string there still are other establishments smart enough about placing their bets with young people who can eventually make whatever new physics is needed).

    The purpose of doing what Smolin suggests and diversifying programs in US departments and institutes etc, and tuning the support system more for individuals IS SO THE US CAN CATCH
    UP.

    Well that is my take on it, M. At least for tonight.

  18. M says:

    Anonymous wrote:

    Maybe by tinkering with the support system you can get more people who are intellectually independent, resourceful, inventive, motivated to solve fundamental problems, and who take seriously (possibly conflicting) well-established physical principles.

    I don’t know whether there is a clear answer to the question of whether an improved “support system” will lead to an influx of the kinds of new ideas that are needed. It certainly seems clear (to me at least) that a friendlier intellectual and funding environment will bring greater diversity, but whether this diversity actually accomplishes the desired goal of reinvigorating fundamental theoretical physics with productive new directions is much less clear. After all, the problem seems less one of “not enough new ideas” as one of “not enough productive new ideas.”

    A key question is what is the origin of the shortage of ideas today. Perhaps it is because

    [1] the key problems are hard, and so the only failure (if it is to be called that) is insufficient effort;

    or maybe it is because

    [2] the key problem is that we are making flawed assumptions about the form (or ingredients) of a more fundamental theory, in which case the failure is one of imagination or insight rather than effort.

    It seems impossible at this point to really know which of these (or maybe some an entirely different cause) is where the greatest problems lie. It seems clear that since the standard model solidified, many very smart people have attacked the problems from a (admittedly limited) number of angles, and thus far none has resulted in anything that looks like a genuine success. If explanation [1] is correct, then I would agree with Curious when he says,

    Whether a testable physical theory is the result of tinkering of many or a protean tour de force by a single genius is of little importance.

    Chris Oakley seems to concur when he says,

    I would therefore advocate the relatively unambitious program of examining weaknessness in existing theories, or in one’s understanding of existing theories and seeing if one can patch these up in any way.

    Certainly it is hard to argue with the statement that as long as you stick close to what is known your effort is less likely to be wasted! But whether that will be enough to break the logjam is an entirely different question…

    On the other hand, if explanation [2] is right then maybe it will take an original thinker to take the first steps. Once that is done, I believe there are enough very capable and willing physicists to flesh out a new theory, much as was done during the development of quantum mechanics or the standard model. In this sense, such an original physicist would resemble an artist of exceptional ability — an ability to see past what seems self-evident with the necessary insight to capture the essence of what is needed.

    Personally, I think that some of explanation [2] is valid. Given the enormous effort by many people of very high caliber over a long time, pursuing a number of different paths, it seems to me that some significant assumptions are being made that aren’t quite right. I would certainly argue that the theoretical edifice that has been empirically verified thus far will remain intact at least in the form of effective theories; one can’t argue with success, and the successes of the standard model and GR, for example, are pretty evident. But it seems quite possible that some of the assumptions that went into the construction of these key theories were not entirely right or fundamental, and it is our mostly unquestioning assumption of the necessity of those assumptions that could now be keeping us from making significant new progress toward what will be an eventual new theory. This is speculation, of course. And even if it is correct it does not mean it would take another Einstein to take the first key steps.

  19. Chris Oakley says:

    I think Curious’s comments are quite apropos. One reason why the inventors of quantum mechanics and relativity disappeared from view in the latter half of the 20th century was that they were looking for another revolution. Unfortunately for them, quantum mechanics and special relativity turned out to be pretty good, and not in any obvious need of revolutionising. And – whether the practitioners admit it or not – overambition has also been the bane of string theory. Try to do too much and you will end up doing nothing. And if they say, “At least we showed that XYZ cannot be made into a physical theory”, one should simply point out that the universe of theories that do not work is potentially infinite, and creating new rays within it not an especially good use of one’s time.

    I would therefore advocate the relatively unambitious program of examining weaknessness in existing theories, or in one’s understanding of existing theories and seeing if one can patch these up in any way. It may sound boring, but at least one is morely likely to have something to show for it.

  20. Alejandro Rivero says:

    And I think what M says he “doesn’t buy into” boils down to the essay TITLE.
    Yep, the title is misleading. One must notice that Smolin has suffered more pression about the concept of “New Einstein” because a popular magazine charged him with such title, some years ago. As I told before I had preferred “a new Sommerfeld” or something so.

  21. Curious says:

    I risk to repeat myself, but I would like to answer M and also once again turn the
    discussion to two inter-related topics: (a) are any
    administrative or reorganizational actions
    on the part of physics community
    like those advocated by Smolin
    would lead to the emergence of a new Einstein? and (b) Do we need this new Einstein?

    We all know that none of Smolin’s suggestions will bring a new Einstein to
    existence. Useful as his advice may be
    in improving the climate in which the research
    is done, there is no guarantee that such a
    climate would help to bring this peculiar goal about.
    Neither it will help to make people more
    open to radical ideas, as that would require changing the human nature. Only a great crisis in physics
    (say, nothing but SM from LHC) would do that.
    Nobody and nothing stays in a way of creativity of today’s generation of theorists: no gurus,
    no cliques, no government policies, nothing.
    It is all in the head. Independent thinkers
    will overcome any pressure and any obscurity,
    if their theories are correct. The best way
    to bring Einstein is perhaps to cut federal
    support completely; then only dedicated
    people will remain and we will be back to the era of gentlemen scientists (when there was explosive development of science and true opennes to ideas); but I am not suggesting
    that. The resistance does not matter.
    Both quantum mechanics
    and SR met tremendous resistance at
    first. Did that stop Bohr or Heisenberg or Dirac? No, it did not. Just take my word, when the
    correct theory emerges it will take us all by
    storm, no matter what and who gets which grants
    and how much, what cliques currently exist,
    what opinion Witten has, etc. That happened
    before and it will happen again.

    M correctly points to the fact that highly talented, original thinkers make great advances in mathematics, music, etc. That whole new vistas can be opened by such people. Symphonies and certain mathematical constructions would not emerge without them, ever. True.

    But physics is not mathematics. Nor is it
    artistry. Whether a testable physical theory
    is the result of tinkering of many or a protean
    tour de force by a single genius is of little importance. Quantum mechanics has been
    developed in many small steps. So is QFT.
    So is analytical mechanics. Laplace, Hamilton
    etc were not Newtons or Einsteins but they
    did a great job w/o which there would not be
    Maxwells and Einsteins. I am not advocating team
    work and doing TOE by a committee of
    mediocrities. My point is different. We do not
    need a new Einstein. We need 10 Schwingers, 5 Bethes, 6 Heisenbergs, 3 Bohrs, 7 Wigners, 4 Weyls and an occasional Landau. You can change this formula however you like. That would do, believe me, if these
    people will pursue their interests with open minds. Please, do not wait for this new Einstein to appear and solve all the problems.
    In physics, you do not have to be a genius to
    do the work of a genius. Forget about the violin and the high moral ground; not needed for job.
    You can do it too, just try.

  22. John Rennie says:

    Since we’ve mentioned physical intuition, can anyone tell me the physical interpretation of local gauge symmetry. Such Googling as I’ve done has failed to find anything beyond a comment (I’m afraid I forget the source) that “it represents hidden degrees of freedom in the theory”.
    Given how central the concept is to field theories I’m a bit surprised how much it is glossed over. Maybe the next Einstein could start by asking what physical mechanism is responsible …

  23. Anonymous says:

    Thomas Larsson offered a nice concise argument here which I will try to respond to.

    [[…For almost five years, I have publicly said that string theorists are barking up the wrong tree. Why should I now be afraid of saying that the much smaller LQG community is doing the same thing (a different tree, admittedly, but still wrong)? Basically I’m using the same argument. Diff anomalies simply must be relevant to the quantization of gravity, because GR has many constraint subalgebras isomorphic to infinite conformal symmetry in 2D, any the lesson from string theory is that these subalgebras generically have anomalies. And no, I certainly don’t think that people at Loops 2005 neither appreciate diff anomalies nor know very much about them.

    Posted by: Thomas Larsson at June 12, 2005 02:58 PM ]]

    “saying that the much smaller LQG community is doing”:

    Thomas, I do not think you know what the much smaller LQG is doing. I keep a casual watch on the literature and would say that those not involved with cosmology are mostly doing path integral-type stuff. You seem to think that your discussion of constraint algebra is relevant, but it is not clear why.

    “Diff[eomorphism] anomalies simply must be relevant to the quantization of gravity, because GR has many constraint subalgebras isomorphic to infinite…”

    Are you SURE that diffeomorphisms MUST be relevant? One center of interest in the LQG community is an approach where there is no differentiable manifold representing spacetime. No differentiable manifold means no diffeomorphisms. No diffeomorphisms means no anomalies.
    In this approach (CDT) the continuum is approximated by piecewise linear manifolds. The behavior of the continuum is described in the limit as the size of the triangulation goes to zero, and the continuum in the limit is neither smooth nor of the same dimensionality at all scales.

    It is not obvious why “diffeomorphism anomalies must be relevant to the quantization of gravity”, especially in path integral approaches, or in approaches where there are no constraint algebras, or where there are no diffeomorphisms.

    Since it is not obvious, perhaps you would like to give a detailed explanation.

    Thomas you say Smolin’s essay is “problematical” because following its results would result in more support for LQG people (doing whatever LQG people do these days).

    You argue that these LQG people should not get more money because they do not know some things you know about diffeomorphism anomalies.

    I get the impression that you do not know who the LQG people are or what they are working on. I have seen you sometimes citing some older papers of Thomas Thiemann and Abhay Ashtekar, papers which do not seem at all typical of either Ashtekar’s current work or the research going on in the LQG community.

    Maybe you should actually GO to the Loops 05 conference this October and see who actually are these people and what actually are their researches towards which you are making the blanket statement they should not get additional funding.

    Then you might have a different idea of who is barking up what wrong tree. It might be you 🙂

  24. Anonymous says:

    to return to the topic of Smolin’s essay, M made a point on 11 June that I don’t think got enough consideration

    [[…

    It seems to me that certain aspects of Einstein’s personality are quite important to his ability to achieve the impact that he did. In my opinion the combination of several key traits was crucial:

    1. Excellent physical intuition.
    2. Great respect for established results. This characteristic strongly distinguishes serious scientists from crackpots.
    3. Willingness to pursue an independent direction, but only when it was apparent to him that the conventional approach was inadequate.
    4. Inwardly directed and motivated. He didn’t let others decide for him what he should be working on or what approach was correct.
    5. Tenacity. He didn’t give up on problems he was interested in, neither because they were hard nor because others didn’t buy into his program.

    As for the connection with Smolin’s article…

    I think all of the above characteristics (and others) were very important to his success. I also think it is clear they came from inside him as an individual and were not the product of an especially nurturing environment or support system. None of his best work was done while he was at the IAS at Princeton, although at the IAS his environment offered an environment much closer to what Smolin advocates than the environment where he did his best work.

    So, I guess I don’t really buy into that part of Smolin’s thesis that states “the system” shoulders much of the blame for “no new Einstein.” If and when someone like Einstein comes along, he or she will succeed primary due to internal motivations and traits, not because Smolin’s proposals have been put into place. Groupthink in physics departments and within funding agencies, hiring decisions based on having a clean record of “correct” research endeavors, and funding decisions based on their compatibility with fashionable research programs and directions are cancerous and harmful to the progress of physics, I agree. But do they prevent the appearance of a new Einstein? I really doubt it; I don’t think obstacles in the system can stop someone like that…

    Posted by: M at June 11, 2005 10:36 PM]]
    *************
    My comment on M’s post is
    I would say that Smolin’s essay has two distinct messages:

    A. Diversify the theoretical research programs represented in departments, institutes, at conferences (incidentally giving young researchers more choice and better information about alternative lines of theoretical investigation). Arguments could be used similar to those applicable in the case of monopoly power and the suppression of economic competition.

    B. Reallocate support more towards the individual researcher (with choice left open) and less by program. Perhaps this would mean longer-term postdoc fellowships awarded NOT on the basis of the pre-established program to which the recipient is indentured, but instead on personal criteria that allow more scope in the choice and invention of research goals.

    And I think what M says he “doesn’t buy into” boils down to the essay TITLE. And if so, I strongly agree. Part A, diversify programs with more competition between rival approaches, does not have any obvious connection with Albert Einstein in 1905.
    Einstein is not a symbolic or informative example relevant to that.

    Nor is his life a very good argument for Part B, says M, because Einstein represented a rare combination of intellectual and moral qualities which you can’t get by tinkering with the system.

    Maybe by tinkering with the support system you can get more people who are intellectually independent, resourceful, inventive, motivated to solve fundamental problems, and who take seriously (possibly conflicting) well-established physical principles. Maybe you can get more ordinary-caliber serious creative people, which would be great! Those people are not necessarily new Einsteins though. I am all for Part B of Smolin program. But the identification with Einstein seems corny.

  25. Kea says:

    Is that you, Marcus?

  26. Anonymous says:

    Dan, you ask:
    [[ …let us suppose string theories’ open problems continue to remain open, and that LQG is able to show it has a semiclassical limit in agreement with GR.
    Would you predict a mass exodus from strings to loops? or is academia such that strings will remain dominant, and LQG marginal?]]

    I take LQG broadly defined as “What LQG-people are doing” and as what will be the main focus at the Loop 05 conference. The Loop conference will feature CDT as one of its main attractions. For an idea of where it stands on “SEMICLASSICAL LIMIT” see this paper

    http://arxiv.org/abs/hep-th/0411152
    A semiclassical universe from first principles

    For additional detail on this and other developments see this one:

    http://arxiv.org/hep-th/0505154
    Reconstructing the universe

    Other basic CDT papers:

    http://arxiv.org/abs/hep-th/0404156
    Emergence of a 4D world from causal guantum gravity

    http://arxiv.org/abs/hep-th/0505113
    Spectral dimension of the universe

    http://arxiv.org/abs/gr-qc/0506035
    Counting a black hole in Lorentzian product triangulations

    http://arxiv.org/hep-th/0105267
    Dynamically triangulating Lorentzian quantum gravity

    In this approach spacetime is not modeled by anything with a differential structure or smooth coordinates. For instance the largescale dimension can be 4D and the dimension decline continuously down to near 2D at very small scale. This is not what one expects with, for example, a differentiable manifold where the dimension must be a whole number corresponding to the number of coordinate functions.

    this year we are beginning to see a shift of LQG-people’s interest towards CDT. Actually it began around May 2004 with the Marseille LQG conference. this is a movement of interest within the general (broadly interpreted) LQG field. You speak of
    an “exodus” from string but from my point of view this does not seem to matter as much as the shift of interest and resources inside LQG.

    Dan you said:

    [[I was thinking of spin network formulation, although one of Lubos’ criticism is that there is no clear connection between the Hamiltonian formulation and spin networks. Is there are clear connection between canonical quantization and causal sets or dynamic triangulation?…]]

    You may mean “spin foams” and not spin network since spin networks are basic to canonical-LQG (the formulation that requires a Hamiltonian constraint). Spin networks form the basis of the kinematic state space of vintage LQG.

    On the other hand spin foams is a path integral approach and fortunately they are not equivalent. Lubos is quite correct that there is no clear connection! However this is hardly a criticism.
    It just illustrates that the broad field of LQG contains several different approaches to quantum gravity.

    Are their “clear connections” from spin foams to causal sets to dynamical triangulations? ABSOLUTELY NOT! It is just that similar skills and intuition apply and similar concerns and problems are important. And the same people (LQG-people) easily cross over and work on the various differnt approaches.
    And the different approaches show up at the same conferences.

    Vague connections yes. Formal logical provable connections no.

    I should enter a disclaimer. I watch research in this field with considerable interest, as it is currently progressing rapidly and is exciting. But I am not an expert and dont do research in it. If I was to go into any kind of LQG (broad sense) research it would be CDT, without question. Very new so basically can get in at ground floor.

    dan you say:
    [[ do you know what the current research in LQG is on the Kodama state, which according to Lee Smolin
    http://arxiv.org/abs/hep-th/0209079,
    has a good semiclassical limit with a positive cosmological constant. I am aware Witten has argued the state is unphysical.
    http://arxiv.org/abs/gr-qc/0306083%5D%5D

    these are old papers, a fair amount has been written about Kodama since then. probably arxiv search engine can find it. recent papers by Stephon Alexander and two people at UBC. use arxiv search to track them down.

  27. Peter says:

    Hi Dan,

    I don’t think that many string theorists will abandon string theory for LQG, even if everyone agrees that LQG has the right classical limit. For one thing, the whole landscape story shows that many string theorists would rather abandon doing science than abandon string theory. For another, many string theorists are, like me, basically particle theorists, and would take the attitude, that if LQG works it just means there are two ways to do quantum gravity, but since the string theory way is supposed to explain particle physics, it is better and they will keep doing it.

  28. dan says:

    Hello Pete,
    short of a no-go theorem, I suppose the work on the semiclassical limit could continue on for an indefinite time. i agree with you though that the current commitment to string theory research is out of proportion to string theory’s tangible physical results.

    Based on Smolin’s analysis of academia, let us suppose string theories’ open problems continue to remain open, and that LQG is able to show it has a semiclassical limit in agreement with GR.

    Would you predict a mass exodus from strings to loops? or is academia such that strings will remain dominant, and LQG marginal?

    Hello At,

    I was thinking of spin network formulation, although one of Lubos’ criticism is that there is no clear connection between the Hamiltonian formulation and spin networks. Is there are clear connection between canonical quantization and causal sets or dynamic triangulation?

    As for the spin network, do you know what the current research in LQG is on the Kodama state, which according to Lee Smolin
    http://arxiv.org/abs/hep-th/0209079,
    has a good semiclassical limit with a positive cosmological constant. I am aware Witten has argued the state is unphysical.
    http://arxiv.org/abs/gr-qc/0306083

    i know Smolin was workign on a paper in response to Witten, which John Baez pointed out, but what has become of this?

  29. Anonymous says:

    Dan, here is the list of non-string QG topics selected for the October
    “Loops 05” conference
    http://loops05.aei.mpg.de/

    Background Independent Algebraic QFT
    Causal Sets
    Dynamical Triangulations
    Loop Quantum Gravity
    Non-perturbative Path Integrals

    It is not always clear how inclusively the term “LQG” is being used. Ten years ago LQG referred to a CANONICAL QUANTIZATION approach to GR, in which dynamics was to be implemented through the Hamiltonian constraint. In the mid-to-late 1990s LQG researchers experienced difficulty with the Hamiltonian and in particular with the associated constraint algebra. Largely on this account, many if not most LQG people moved over to path integral approaches including SPIN FOAMS, CAUSAL SETS, and DYNAMICAL TRIANGULATIONS.

    Today, very few LQG are actively pursuing canonical quantization of GR. An exception is Thomas Thiemann at AEI who has something called the Master Constraint program.

    There is a LQG program developed by Gambini and Pullin which looks somewhat like canonical LQG, but which has no constraint algebra and no Hamiltonian constraint. Its Hamiltonian is a discrete time-evolution operator.

    Anyway we have a confusing abuse of language here. Almost everybody seems to use “LQG” as a blanket term for the non-string, mostly path integral, approaches to QG. There is no other widely recognized blanket term for what LQG people do!

    But then some people, it would seem Thomas Larsson is a case of this, proceed to talk about the “LQG” in a much narrower sense, as if it were the canonical quantization program of the 1990s that has already been described in several books—the approach that encountered difficulty realizing Hamiltonian constraint dynamics.

    Now I am wondering which “LQG” you mean, dan? Here is what you said:

    [[..How many years are you willing to give “LQG” and its attempt to recover the classical limit before you deem it a failure? and if it is unable to find such a limit within a specified time period, would it be fair to say that LQG is as failed a project as string/m-theory.

    Posted by: dan at June 12, 2005 03:08 PM ]]

    The non-string QG approach that many people would consider closest to “recovering the classical limit” would be CDT, I suppose (causal dynam. triang.) That was invented in 1998 (the year the first two CDT papers were published). It first produced a 4D spacetime in computer simulations in 2004. Smolin, who seems to represent “LQG people” for many of us, recently co-authored a CDT paper. There are indications that CDT will be one of the main points of discussion at Loops 05. I cannot say for certain that CDT has NOT “recovered the classical limit”.
    Perhaps I could fetch some links to recent CDT papers and you could decide for yourself.

  30. Peter Woit says:

    Hi Dan,

    First of all, unlike the case of string theory, I haven’t spent much time following the debates and arguments over LQG, so I don’t want to make any pronouncements about either its success or its failure. I’ve explained why elsewhere, basically it’s because I’m fundamentally a particle theorist. String theory has failed because it is now clear it can’t explain anything about unification in particle theory. LQG has never tried.

    In the current situation, where there are no successful ideas about going beyond the standard model, everything people work on is not a success, and thus has experienced some degree of failure. This doesn’t mean people shouldn’t work on these ideas, maybe the failures can be overcome. But the amount of effort that has gone into string theory unification has been staggering, and has provided huge amounts of evidence that the idea can’t ever work. The effort going into LQG has been much more modest, and, although it hasn’t completely achieved its goals, it’s not implausible that with more work some new ideas will be found. I don’t think one can say the same about string theory any more.

    If those working on LQG don’t make any progress during the next 5-10 years, and it really is true that they can’t get out GR in a the classical limit, I suspect most people working in the field will move on to something else. If instead they attract thousands of physicists to work on the idea, and have dozens of conferences each year, some with 500 theorists in attendance, if I’m still around I’ll be spending a lot of time complaining about their behavior.

  31. dan says:

    Hi Peter,
    I do have a question for you,

    I am sympathetic to your claim that String/M theory is currently a “failed” project.

    What I wonder is whether you think LQG is a “failed” project as it has been unable to reproduce GR.

    How many years are you willing to give “LQG” and its attempt to recover the classical limit befre you deem it a failure? and if it is unable to find such a limit within a specified time period, would it be fair to say that LQG is as failed a project as string/m-theory.

  32. Thomas Larsson says:

    Of course Smolin asks for a redistribution of funds from string theory to LQG. After bemoaning the string theory dominance, he complains how difficult it is to find positions for young people in technicolor, preon models, dynamical triangulations, causal sets, and LQG. How can this be construed otherwise than as a call for redistribution of funds from string theory to these areas, in particular LQG?

    String theory surely has problems – there is no theory, no predictions and no experimental support. But this does not imply that large amount of funding should go to research aiming at disproving QM, GR or the standard model. OK, LQG does not aim at disproving QM, but claiming that anomalies can be arbitrarily dialled to zero by a new wonderful quantization method is not far from it. The existence of anomalies does certainly not depend on the quantization method; conformal anomalies arise also in the path-integral quantization of the bosonic string, in the form of Schwarzian derivatives that appear in the transformation law of the measure. Again, they only cancel in 26D.

    In this connection it might be worth mentioning that I was originally trained in statistical physics, where stringy mathematics (read CFT) plays a fundamental role. Unless the situation in HEP, the application of CFT to 2D statphys is a success story, and it has be experimentally verified beyond reasonable doubt. In particular, the central charge has been measured, at least in computer simulations, and it has been found to agree with the non-zero CFT prediction. From this perspective, the idea that conformal anomalies can generically be avoided is absolute nonsense.

    For almost five years, I have publicly said that string theorists are barking up the wrong tree. Why should I now be afraid of saying that the much smaller LQG community is doing the same thing (a different tree, admittedly, but still wrong)? Basically I’m using the same argument. Diff anomalies simply must be relevant to the quantization of gravity, because GR has many constraint subalgebras isomorphic to infinite conformal symmetry in 2D, any the lesson from string theory is that these subalgebras generically have anomalies. And no, I certainly don’t think that people at Loops 2005 neither appreciate diff anomalies nor know very much about them.

    Implicit in section 5 of Nicolai et al. is a suggestion for a research programme: quantize GR in a similar way as the Polyakov action is quantized in bosonic string theory. This is more or less what I have tried to do for 15 years, and at the very least some of the mathematics – the anomalies and many representations – is now firmly understood. However, in my view this is strong evidence against string theory – if previously overlooked mathematics allows GR in 4D to be quantized, there is really no need for extended objects in 10 or 11D.

  33. Anonymous says:

    Thomas Larsson faults Smolin’s essay as follows:
    [[… the suggested cure, which more or less explicitly reads more money to LQG, is problematic since many people feel that the LQG people are ignoring well-established facts.

    Posted by: Thomas Larsson at June 12, 2005 06:13 AM]]

    that is, in Larsson’s view, Smolin’s article is problematic because it advocates more money for LQG people
    and LQG people ignore a well-established fact about constraint algebras which Larsson has discussed on several occasions.

    1. the main thrust of the article is not advocacy of specific research lines. however several are mentioned (foundations of QM, technicolor, preons, QG phenomenology, causal sets, dynam. triangulations, Loop)

    Loop (in the narrow canonical sense, or even the broadly inclusive sense) is not given priority in Smolin’s list. It is hard to see how Larsson can criticize the essay for special pleading or favoritism.

    2. In Larsson’s view it would be problematical for unnamed “LQG people” to get more research funds. Who are “LQG people”. A good working definition would be those who are organizing and speaking at the October Loops 05 conference at the Albert Einstein Institute
    http://loops05.aei.mpg.de/index_files/Home.html

    This link gives the topics to be covered at the conference.

    This other link lists the invited speakers:
    More about the programme
    http://loops05.aei.mpg.de/index_files/Programme.html

    Since you are accusing people of being ignorant of well-established facts, Thomas, which of these invited speakers to Loops 05 do you say are ignorant of well-established facts? I am just curious. Do you know any of them and have you talked with them to be sure that they are ignorant as you say?

    I think maybe some were never ignorant of what you say and maybe some could have been ignorant perhaps a couple of years ago and may have learned something since then. But personally I don’t know. You are making the blanket claim about the ignorance at present time of a group of people—-so that Smolin’s essay is problematical if it leads to them being given more research funding—-and so I guess it is up to you to substantiate it.

  34. Anonymous says:

    Thomas Larsson, it would help if you and indeed all of us (myself included) would look more objectively at what the Smolin essay actually says. I have used caps to emphasize relevant parts. Notice that most of what Smolin is talking about has little connection with what you are talking about (alleged ignorance of unnamed Loop people concerning anomalies and “infinite dimensional constraint algebras”)

    [[Alternatives to strings

    More worrisome, young theorists who pursue alternatives to string theory have had great difficulty finding any academic positions in the US. This is true of those who pursue alternative programs in particle physics, like TECHNICOLOR and PREON models, and also true of those who pursue alternative approaches to quantum gravity, such as DYNAMICAL TRIANGULATIONS, CAUSAL SETS, AND LOOP QUANTUM GRAVITY. These subjects are all pursued much more vigorously outside the US, because leading researchers in these areas are drawn to leave US universities by offers of very good opportunities elsewhere.

    One approach barely represented in the US is QUANTUM GRAVITY PHENOMENOLOGY, which studies how to test quantum gravity theories experimentally by means of high-energy astrophysics experiments such as the Gamma Ray Large Area Space Telescope and the Pierre Auger Observatory. The experiments are supported in the US, but most theorists who are developing the relevant phenomenology are outside the US.

    Other examples show the hazards of too much concentration of resources on a few areas, to the exclusion of others. For decades, the FOUNDATIONS OF QUANTUM MECHANICS got virtually no support in the US; it was believed to be a direction without promise. In the last 10 years the fast-moving field of quantum information has shown that important experimental and theoretical results about foundations of quantum mechanics were always there for the finding…]]

    The approach to quantum gravity which he mentions first, Ambjorn Jurkiewicz Loll CDT (“dynam. triangulations”), is a path integral approach that has nothing to do with “infinite dimensional constraint algebras”.

    Indeed if he is to be accused of special pleading, much of what Smolin mentions in the short passage about specific non-string lines of research do not involve “infinite dimensional constraint algebras”.

    However, you say:
    [[… the suggested cure, which more or less explicitly reads more money to LQG, is problematic since many people feel that the LQG people are IGNORING WELL-ESTABLISHED FACTS.

    Most of modern string theory – M-theory, AdS/CFT, flux compactifications, anthropic principle – is arguably built on loose sand, but some string theory insights are here to stay. LQG, and even more so the LQG string, violate probably the most fundamental insight of string theory: that INFINITE-DIMENSIONAL CONSTRAINT ALGEBRAS generically acquire anomalies on the quantum level…


    Posted by: Thomas Larsson at June 12, 2005 06:13 AM]]

    It has been pointed out here at Peter’s blog, by Smolin himself in fact, that much of the work by LQG-people in the past 10 years has been in the path integral direction—spin foams and the like. This has not involved “infinite dimensional constraint algebras” or any constraint algebras at all.

    I thought Smolin effectively answered Hermann Nicolai’s
    “outsider’s view” article in his letter posted here, by pointing out that Nicolai’s view of LQG research was overly narrow or else some 10 or 15 years out of date. Nicolai’s view of Loop-and-related research has changed radically since that article, judging from the list of topics and speakers for the October “Loops 05” conference which Nicolai’s institute is hosting.

    I think if you take another look at your own post here, of 12 June, you will see that it is not Smolin who is self-serving and trotting out his own favorite hobbyhorse.

  35. Torbjorn Larsson says:

    Curious:

    “GR, basically, hindered the progress in physics as much as it fostered it. Its own creator was not satisfied with this theory and its general validity has not been shown experimentally to this day.”

    I think this is incorrect. I seem to remember that you need GR, not only SR, to construct and maintain GPS satellite systems. Also, I think all the serious contenders have been shown wrong already. If I am mistaken I hope someone more knowledgeable will correct me.

  36. Alejandro Rivero says:

    A related question in some comments here is “Why a new Einstein”, but it seems that most bloggers are driven by General Relativity. IE we want a new Einstein to unify the four forces. So we discuss about LQG (not rare in a thread about Smolin), fundamental strings, etc.

    I a humbler way, let me suggest that a new Einstein taming the strong force could give already enough advance for some years: to be able to calculate particle masses and effective coupling constants (and from it, decay widths and branches) for all the hadronic interactions. I wonder how many of the support for strings comes still from the hope of being able to solve this particular point, independently of higher hopes.

  37. Juan R. says:

    Peter, i repeat my previous question for you if you have time for reply it.

    would be more effective if you could post your comments in string theory (e.g. in Landscape stuff) directly like an attachment to each ArXiv preprint instead of here? That model did already exist in the CPS preprint (unfortunately closed) and worked very well, because one could see the preprint and in the same html page comments/discussion by people.

  38. Juan R. says:

    I agree with several, practically the whole, of Smolin’s points and proposals.

    Four additional comments:

    1) I believe that Smolin article is, at some extension, a reclaim for attracting more people to “nonstandard” quantum gravity research like LQG. There is around 10 times more people working in strings, branes.

    2) The real problem is about money. Past science was less expensive and moreover great advances were done by people with his/her own money. Today many parts of science are really expensive and one need funding or a “Templeton” grant :-). Money implies control of it and control implies directed research and directed research implies the control by mainstream. Less popular research programs are in the last part of the list for obtaining funding. That is a natural outcome of current scientific “democracy”. History shows that in general questions mainstream knowledge is good, but in radical answers, mainstream is just wrong (remember revolutions of past begining in Newton).

    3) A real Einstein, if any today, would not follow current popular research programs. Because a real Einstein (or Newton) would choose elegant, powerful approaches instead of irrelevant theories and ugly programs. A point is sure to me. Today Einstein would not follow current approaches to quantum gravity. None of them is really profound, several are ugly, and many of them are simply wrong.

    4) Where is Wally (i.e. Lubos Motl)? I claim that the first “Einstein-like grant” was given to him for developing his impresive knowledge and physical intuition in quantum, gravity and other topics. All of we would favouring this plea. It is simple, if we leave to him study topic freely, he (great genious) choose the wrong way. The rest of people simply would follow the contrary way and the advance of science in next decades, would be impresive :-0.

  39. Thomas Larsson says:

    M wrote some posts ago
    It seems to me that certain aspects of Einstein’s personality are quite important to his ability to achieve the impact that he did. In my opinion the combination of several key traits was crucial:

    2. Great respect for established results. This characteristic strongly distinguishes serious scientists from crackpots.

    This is the crucial point, isn’t it. It is easy to agree with Smolin’s description of today’s problems in physics, with string theory’s experimentally unmotivated dominance. However, the suggested cure, which more or less explicitly reads more money to LQG, is problematic since many people feel that the LQG people are ignoring well-established facts.

    Most of modern string theory – M-theory, AdS/CFT, flux compactifications, anthropic principle – is arguably built on loose sand, but some string theory insights are here to stay. LQG, and even more so the LQG string, violate probably the most fundamental insight of string theory: that infinite-dimensional constraint algebras generically acquire anomalies on the quantum level.

    It is generally accepted that constraint algebras, like the infinite conformal symmetry of the bosonic string, must be anomaly free. (My opinions in this matter differ and are controversial, although IMO well-founded.) However, the fundamental observation is not really that the conformal anomaly cancels in 26D, but that it generically (D != 26) does not cancel. It is thus no surprise that string theorists (and not only them) reacted strongly when the LQG people claimed that it is possible to quantize the bosonic string without an anomaly for any D. For a detailed argument, see the critical review of LQG by Nicolai et al., especially Section 5, Constraint algebra.

    Thus, given that many people think that LQG is fundamentally misguided, it is hard to feel that it is really under-funded at the present level.

    Incidentlly, my own work can be regarded as an attempt to treat GR along the same lines that string theorists treat the Polyakov action. This is evidently much harder (otherwise someone else would already have succeeded), but I find it rather striking that at least the relevant anomalies have been found, together with large classes of representations.

  40. Scott says:

    um my first sentence of my last post should have ended with “without Einstein” however curious seems to have made that point in a much clearer way then i did/ would have if i had finished the sentence.

  41. M says:

    Hi Curious,

    I may be mistaken in my impression, but it seems like you are missing the main point of Smolin’s article, based on what you wrote:

    “It has been implicit in your discussion as well as in Smolin’s paper that we desperately need new Einsteins to advance physics. The whole controversy then centers on how to get these proto-Einsteins out of obscurity, with or without the violin.”

    I didn’t see that implicit assumption in Smolin’s article. I doubt that his objective was to convince the world that we need a new Einstein to save us from our theoretical morass and lead us to a bright future (with the rest of the article then proceeding to explain how we should clear the roadblocks so this can happen).

    It seemed to me that Smolin was using Einstein as a symbol for independent and creative thinkers who could (hopefully) make significant progress on really vexing problems. He proceeded to outline some systematic, serious impediments within “the system” and gave suggestions for making changes that would reduce them and nurture new approaches. He may be right. But it seems to me that someone like Einstein would find a way to work on the really difficult problems and get his or her work noticed even with the theoretical climate of today.

    As an aside, is it controversial with you that there is a real need today for significant new ideas in fundamental theoretical physics, or that major advances are usually initiated by a small number of people? You seemed to imply that a team effort is a reasonable substitute for exceptional individual talent when you wrote,

    “Except for GR I cannot think of any of Einstein’s theories that would not be suggested by others 5-10-15 years later. … The task that was carried by a single person in 1905 could have been carried by several lesser minds w/o much loss for science.”

    Obviously it is impossible to disprove your statement, but there are many examples of activities where a team or committee of lesser minds is no match for exceptional thinking by a single individual. For example, think about difficult mathematical problems that have resisted long efforts by others until a single person with the requisite insight or creativity came along. Think about especially great works of visual art, literature or music. Can a team of excellent architects create a design that is equal or nearly equal to that of a truly exceptional architect? Would you feel as confortable fighting a battle (military or corporate) that is being led by a committee of excellent strategists as you would one that is led by a truly exceptional strategic thinker? (It also seems worth noting that Einstein played a very key role in the development of quantum mechanics; read Pais’ biography if you doubt this. It is questionable that things would have turned out as they did in the 1920s without his help. Among “all those geniuses in the 1920s,” most were working out consequences and difficulties in the new quantum theory, a much easier task than coming up with a new theory in the first place.)

  42. Scott says:

    Curious,
    It is hard to understand cause and effect properly, were other people finally thinking new ideas because einstein broke the grip of the old ideas with his SR explanation of the photoelectric effect and brownian motion, or would have poincare finnally make the leap (actually i don’t think he ever did either despite of or maybe because of einstein) to SR, and then maybe someone like bohr or heisenberg might have explained the photoelectric effect. The point is the field is in desperate need of some new people(don’t get hung up on the “einsteins”) to get the ball moving towards a new physics by making revolutionary steps toward the reconcilation of QM and GR as well as properly explain things like “dark matter” and “dark energy” among other things. It is these people who may not be quite the timesaver that einstein that need to be recognized and encouraged instead of pushed out of the field by its institutionalism. To do this we need to be able to recognize these thinkers better by changing arxiv and getting universities ect to diversify their speculation.

    Also I would like to remind you that seeing as GR and QM have not yet been reconciled yet it would be foolish to assume the GR has somehow held physics back.

    “He worked hard on these problems. And so should you”
    yep, I am going to do that as soon as my summer starts. Speaking of which I am going to go finish up my labwritups so that I can start working on it.

  43. Curious says:

    It has been implicit in your discussion as well
    as in Smolin’s paper that we desperately need new
    Einsteins to advance physics. The whole controversy then centers on how to get these proto-Einsteins out of obscurity, with or without the violin. I beg to differ. Except
    for GR I cannot think of any of Einstein’s theories
    that would not be suggested by others 5-10-15 years
    later. He was, basically, a terrific time saver, most of the time. It is preposterous to suggest that w/o Einstein there will be no BE statistics, or photons, or statistical
    fluctuation & Brownian motion theories, or special
    relativity – to name just a few topics. Think of all these geniuses in the 1920s; they did that and more. One thing
    I am not certain about is GR. I do not think that
    such a theory would be advanced without Einstein,
    but it might have been better for physics if it weren’t in the end; after 1930 nobody would even think about
    suggesting a nonquantum, purely classical theory of
    gravity. GR, basically, hindered the progress in physics as much as it fostered it. Its own creator was not satisfied with this theory and its general validity has not been shown experimentally to this day.

    I think that we do not need new Einsteins. The task that was carried by a single person in 1905 could have been carried by several lesser minds w/o much loss for science. Perhaps, we just need to think a bit like Einstein and look at old problems with fresh eyes. One can hope that a
    new Einstein will come and clear the slate for you.
    Or one can look for new ideas w/o counting on that.

    Surely, the second coming of A.Einstein would be helpful. However, delegating the responsibility to find new things to others is not dignified. Who
    and what prevents YOU from seeing the obvious? Funding agencies? Peer opinion? Latest fads? Stop fooling yourself. Getting new ideas has always been difficult. It is YOU yourself. And I am no better than you.

    Einstein did not write papers in the 50s that he
    needs a new Newton to help him out of his TOE problems. He worked hard on these problems. And so should you. Enough of this new Einstein nonsense.

  44. Scott says:

    M,
    Anonymous was the one trying to shut down an avenue of discussion, if he wanted smolins proposal’s discussed, he should do more then say hey lets talk about these I think they are good instead of saying hey smolin said this I think this about it. Granted he did put some thoughts on it such as its good but all he said was I think these are good suggestion but I would like this suggestion checked out and think this other suggestion should be done carefully. Not knowing the answer to his one question and seeing nothing else to talk about I choose to explain why I thought my comments on changes to the arxiv and other comments about why were on topic in the fact they further the thinking in the question Smolin is attempting to answer thus in a way critiqueing for the points if overlooks if you need to look at it that way to justify the thread drift. So lets get the story straight anonomyous was trying to limit the direction of thought about why no new Einstein solely to discussing Smolins points and forcing us all to think(or at least restict our conversation) along only those lines, allowing no others. Do you see the parrallel? That parrallel to the main reason cited for their being no new Einstien was what i found so hilarious, i am sorry if it came off as insulting but it was really funny too me, i actualy did laugh out loud about it(granted I was really sleep deprived at the time). As far as I know Peter only gets worried about the thread going off topic when posters pet theories get brought up and discussed to much which hasn’t happened in this thread.

    That being said I think you are dead on with your description of his personality and how this would lead to his success even despite our current institutional problems. But what about the “miniEinsteins” those who are very similar to einstein and capable of thinking of revolutionary ideas but without as strong a drive to do so despite the institutional problems we have. Why should, many others who made creative and revolutionary ideas didn’t have to succeed despite this. In that sense we should still try out these suggestions and Juan and my suggestions about changing the arxiv for better communication in order to facilitate these individuals. Of course all of this is mute if a genuinely “new einstein” in the sence you are speaking of blasts on to the scene as such an event would lead to a more revolutionary thinking among others as well as break the institutional hold. Personally I have odds on the real deal showing up and making this discussion mute, but just in case…(of course this just type of waiting for an “Einstein” really brings back my messianic complex comment)

  45. M says:

    As a follow-up to the anonymous poster:

    “Let’s not distract ourselves with details about the personality of Albert Einstein and his symbolic life experiences. Maybe there is hope of a generational shift and qualitative improvement in US research institutions.”

    It seems to me that certain aspects of Einstein’s personality are quite important to his ability to achieve the impact that he did. In my opinion the combination of several key traits was crucial:

    1. Excellent physical intuition.
    2. Great respect for established results. This characteristic strongly distinguishes serious scientists from crackpots.
    3. Willingness to pursue an independent direction, but only when it was apparent to him that the conventional approach was inadequate.
    4. Inwardly directed and motivated. He didn’t let others decide for him what he should be working on or what approach was correct.
    5. Tenacity. He didn’t give up on problems he was interested in, neither because they were hard nor because others didn’t buy into his program.

    As for the connection with Smolin’s article…

    I think all of the above characteristics (and others) were very important to his success. I also think it is clear they came from inside him as an individual and were not the product of an especially nurturing environment or support system. None of his best work was done while he was at the IAS at Princeton, although at the IAS his environment offered an environment much closer to what Smolin advocates than the environment where he did his best work.

    So, I guess I don’t really buy into that part of Smolin’s thesis that states “the system” shoulders much of the blame for “no new Einstein.” If and when someone like Einstein comes along, he or she will succeed primary due to internal motivations and traits, not because Smolin’s proposals have been put into place. Groupthink in physics departments and within funding agencies, hiring decisions based on having a clean record of “correct” research endeavors, and funding decisions based on their compatibility with fashionable research programs and directions are cancerous and harmful to the progress of physics, I agree. But do they prevent the appearance of a new Einstein? I really doubt it; I don’t think obstacles in the system can stop someone like that…

  46. M says:

    Scott wrote:

    “No one is objecting to his suggestions here this indicates we all agree, and so we moved onto discussion about other things to incourage revolutionary thinkers and better ways to recognized them and their ideas in the arxiv.”

    I don’t think anyone appointed you as spokesperson for what everyone else thinks. Peter’s topic was Lee’s article, ‘Why No “New Einstein”?’ It seems quite inappropriate to try to shut down discussion on that in favor of steering discussion to less on-topic areas (and in an insulting manner, at that). Recall Peter’s explicit requests on a number of occasions to maintain discussion on the particular topic; that the anonomous poster was trying to do this is to be encouraged rather than disparaged.

  47. Scott says:

    anonymous,

    No one is objecting to his suggestions here this indicates we all agree, and so we moved onto discussion about other things to incourage revolutionary thinkers and better ways to recognized them and their ideas in the arxiv. Personally I find the fact that you are simply wanting to simply discuss Smolins proposals instead of having us think of more proplems and proposals, is in the context of this topic extremely hillarious, I’ll leave it to you to figure out why.

  48. Anonymous says:

    I continue hoping for some discussion of these three substantive proposals of Smolin

    quote from June “Physics Today”

    To prevent overinvestment in speculatative directions that may end up as dead ends, departments should ensure that different points of view about unsolved problems, and rival research programs, are represented on their faculties.

    Research groups should seek out people who pursue rival approaches, and include them as postdocs, students, and visitors. Conferences in one research program should be encouraged, by those funding them, to invite speakers from rival programs. Instructors should encourage students to learn about competing approaches to unsolved problems, so that the students are equipped to choose for themselves the most promising directions as their careers advance.

    Funding agencies and foundations should take steps to see that at every level scientists are encouraged to freely explore and develop all viable proposals to solve deep and difficult problems. Funding should go to individual scientists for individual thought and not to research programs. A research program should not be allowed to become institutionally dominant until supported by convincing scientific proof of the usual kind. Before such proof is demonstrated, alternative and rival approaches should receive encouragement to ensure that the progress of science is not stalled by overinvestment in a direction that turns out to be wrong.

    —-end quote—

    Does anyone doubt that these three of Smolin’s proposals should be put into effect? Could some governing body in NSF adopt them as resolutions, or is that too much to ask? Could someone with an agenda like Smolin’s be appointed to a position within NSF from which leverage can be applied to the major physics departments and the relevant agencies and people at various levels. If that is too much to expect, then why, exactly, is it so?

    If the US scientific establishment has reached a point at which such proposals actually need to be made (instead of being implemented per custom in normal academic practice) then can anyone here offer any objection to their adoption?

    Let’s not distract ourselves with details about the personality of Albert Einstein and his symbolic life experiences. Maybe there is hope of a generational shift and qualitative improvement in US research institutions.

  49. Anonymous says:

    [[ I thought this was about why their was no “new Einstein,” silly me. Adding to Smolin and Peters comments on why this is…

    Posted by: Scott at June 11, 2005 11:14 AM ]]

    Of course you are welcome to think that. Please allow me to suppose something different. I suppose that the headline question of “why no new Einstein” is essentially just good journalism.

    It gets attention, dramatizes the issues, and I suppose energizes people by involving them in emulation fantasy.

    One could also as “why no new Feynman” or “why no new Kepler”.

    but allow me to suppose that this is simply a journalistic hook and that the substance of what he is talking about is as follows:

    1. he claims (dont know if true) that creative independent-minded talent that you would earlier have expected to stay in US is going to places like Europe and Canada.

    this could be, e.g., a talented young European, proven innovator, who comes to US for postdoc and then instead of moving on to faculty at Columbia or Princeton (as he or she might have done in years past) goes back to Utrecht or Potsdam.

    I dont know what statistics Smolin is talking about. he is saying US theory establishment is now COMPARATIVELY LESS ATTRACTIVE to bold ingenious workers and that the lucky ones are LEAVING. Maybe he is wrong. and maybe he is right. It needs to be checked.

    2. He is saying that to make the US more attractive again, to foster and keep these people, certain re-diversification should be done by

    a. department chairs, hiring committees, tenure review
    b. research institute directors, conference organizers,
    c. NSF committees, foundations that fund conferences, fellowships, etc.

    This diversification is more along the lines of having SEVERAL RIVAL programs or theoretical approaches represented in the department, or the research institute. One of the best examples of this is the Albert Einstein Institute at Potsdam which has several quantum gravity approaches being pursued.

    3. He may also be saying loosen the institutional grip which vested research programs have on theory in major departments, at least to the extent they turn the inventive young person into a brain-slave. But in my private estimation this should be with some care, if at all, since if applied heedlessly it could damage the coherence of valuable efforts.

    In any case I think it is sentimental nonsense to think that one is going to find some policy change that will produce people that will be recognizably similar to those whom we revere as heros and saviours, “new Einsteins”, or Keplers, or Feynmans or whatever. A practical objective would be to make US research institutions once more attractive to talented independent minds, if necessary by breaking the monopoly power of overgrown programs.

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