Witten Away From the Energy Frontier

Edward Witten has been visiting CERN this past academic year, and it seems that besides continuing to work on things related to geometric Langlands (see his recent talk at Atiyah80), he also has been returning to his roots as a phenomenologist, and taking a wide interest in a range of phenomenological questions being discussed at CERN.

Next week CERN will be hosting a workshop on New Opportunities in the Physics Landscape at CERN, to discuss experiments at CERN over the next 5-10 years that are NOT directly related to the LHC. Witten will open the workshop with a talk on Perspectives in the Physics Landscape away from the Energy Frontier, and his slides are already available. He comments on a variety of topics, including CMB measurements relevant to inflation, neutrino masses and mixings, proton decay, CP violation and axions, and dark matter candidates. All in all, it’s a quite comprehensive survey of how possible non-LHC results might address beyond Standard Model physics questions, mostly from the point of view of the now conventional speculative framework of Supersymmetry/GUTs/String theory.

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15 Responses to Witten Away From the Energy Frontier

  1. Haelfix says:

    Witten did some beautiful work in phenomenology, including a bunch of obscure but still highly relevant gems like his work on neutrino physics.

  2. M says:

    I wonder what is the opinion by Witten about using a novel non-scaling FFAG or a SC-linac feeding a system of accumulator and compressor rings to limiting the duration of pulses below a few msec in a 50 Hz proton driver?

  3. Greg says:

    The most saddening aspect of Witten’s slides are that he is excited about the many possible theoretical options. (See the slide before last, for example). One day we will have the final theory, and we will know that all options except one are wrong. So how can one be excited about the existence of many options? It just means that unconsciously, one has given up on distinguishing the true from the false, one has given up on finding the correct option.

    Witten was my hero in the 1990s, when in an interview he stated that he decided to dedicate his life to finding unification. Now he is excited about many options. In short, he has given up. That is incredibly sad!

    It is sad that in order to remain friends with colleagues, we all feel forced to cite all their toy models, as weird as they may be, without saying that they are wrong. Worse, we do not use these mistakes to narrow our search, but we use them to widen it. That is a disservice we do to students – and to ourselves.

    We will never find the toe if we do not “cut the crap”. Anybody has the right to publish on any topic, but we need to make use of all these mistakes to proceed. We (the community of physicists) are not doing that, at present.

    Another person, who liked to cut the crap has given up doing so: Motl. We can all notice that he cuts the crap only in topics far from his own field. In string theory, he rarely does so. Thus he will not advance to the toe, even if it is inside string theory! (remember his post many years ago were he speculated the direction to go? He did not follow it up himself, nor did he ever correct the aim.) All these are examples were people prefer to stay friends than to search for the true theory.

    Peter, you cut the crap, and we all admire you for this. Let us go on – life is too short. We now need to clarify the mistakes done in the past and provide guidance, for ourselves and others, into the right direction for the search.

    Woul it be possible to open up a new speculative tag on your blog, called something like “lesson of the week” (partner of “hype of the week”) in which you/we all clarify (1) which ideas have to be dropped from the search for the toe, and (2) which ideas have to be retained?

    Nobody is doing this in public in the whole world; who else but you can do it?

  4. anon says:

    Who are you? You’re supposed to teach Edward Witten, 339 papers and 87,000+ cites old, what is the right path to take and what’s wrong? Hilarious!!! Just that he said other options are exciting doesn’t mean the options are right..

  5. Francis says:

    If I read the post, Greg is not telling Witten what to do, he is writing only about his own sadness. Greg’s point and reason for sadness is that Witten has given up searching for the toe.

  6. anon says:

    oh really? as I read it, the word ‘sadness’ seems to enrobe his firm conviction that Witten has given up on unification and instead is promoting other people’s ideas to stay in their good books, which I think is plain accusal of a great scientist.

  7. Francis says:

    No, it is much worse, Greg is saying that all physicists, including himself and “anon”, are too kind to false ideas in order to remain friends, and that this is the reason that the toe has not been found.

  8. BigG says:

    You people should be careful about using the term TOE. First of all the name is misleading as it would not be a theory of everything. Second, even as physicists intend it, there is no certainty it is possible or even an existent. If a point was reached that was labeled TOE, there is no way of being certain that’s it. A further objection is that a TOE would be something that is not subject to further investigation, implying something that exists independent of anything else. This concept is highly problamatic. Physics lost its way when it decided philosophy had nothing to offer.

    The biggest problem with physics today is those attempting to push the edge of theoretical physics are still stuck in the mindset that made the standard model so successful. This kind of thinking would not have been beneficial in the early 20th century and is holding back progress today.

    Its a difference between technicians and thinkers.

  9. Peter Woit says:


    The whole problem with beyond the SM physics is that no one has any really compelling ideas. Witten gives a good survey of some of what is out there, but that doesn’t mean that he’s claiming they are convincing. Like everybody, he’s hoping for some unexpected experimental result that will show the way….

  10. anon says:

    It would be better if you speak for yourself Mr. Greg, rather than for the whole physics community as such and Witten in particular, I think Woit’s point explains it better..

  11. anon2 says:

    I think its important to contrast these two statements…

    “Who are you? You’re supposed to teach Edward Witten, 339 papers and 87,000+ cites old, what is the right path to take and what’s wrong? Hilarious!!!”


    “Science is the believe in the ignorance of the experts”

  12. Paul says:

    But is there any physics beyond the standard model? (I’m counting neutrino masses as part of the standard model.) This is not sure at all. Some argue that no argument for the existence of physics beyond the standard model is really watertight. A likely situation is that the LHC find one Higgs and that is it, and none of Witten’s experiments finds anything. We would not be smarter than we are now.

    Then Greg’s proposal for a “cut the crap” approach might be useful. In fact, if higher dimensions and supersymmetry are dropped because they are “crap”, then there are only extremely few options left. But nobody seems to want to explore them.

  13. FNesti says:

    I agree that Witten’s slides were quite disappointing.

    Lack of new ideas or hints.. (ok, this is hard for everybody, but I was expecting something more.) All theories on equal footing – those with predictions and those with none. Superficial analyses..
    And more importantly: the lack of insight, of taste, of understanding of the relations among things, of hyerarchy among problems..

    It was something like a student’s talk, just a list of possibilities – as if one studied phenomenology just the night before.

    So the sad point to me is to realize that, after having provided outstanding contributions to Physics, one can go so far to loose the contact with the real problems. That is to me, the main lesson – be careful not to loose too much contact with physics. Then, no doubt Witten will be back on topic very soon if he wants.

  14. Peter Woit says:


    I don’t think Witten’s problem is having lost “contact with physics”. He’s very much in contact with the activities of phenomenologists (and always has been), and his talk reflects the conventional wisdom of the field. To expect some insights into phenomenology from him that are dramatically deeper than those of other experts is unreasonable.

    One could perhaps make a stronger argument that he (and many other theorists) are too much in “contact with physics” now, that until something new comes out of experiment, time is better spent doing what they are best at, trying to get a better understanding the formal underpinnings of the subject. But, I agree with other commenters that offering Witten advice about how he should be choosing to spend his time is rather silly…

  15. FNesti says:

    Hi Peter,

    well, I do was expecting something more – some concrete points:

    Neutrino masses – is it really a surprise the “largness” of the neutrino mixings? (to me this is a naive and misleading observation..) should this be mentioned in a talk?

    GUT – in reality there is no prediction of the GUT scale, beyond say 10^14. There are models where proton decay can be suppressed and you can lower the scale .. there are models where the additional mattter content before GUT pushes the scale up to MPL. What one can say is just that the idea is not ruled out by unobservation of proton decay, a fairly weak statement (sad for older generations, not for the new ones). Also SUSY is really a non-theory, when you look at the few complete real models you find big uncertainties from soft terms.. or any sort of fragments in the desert so no real connection with the weinberg angle.. no real connection between GUT and neutrino masses. I would have hoped to see some of this noticed.

    p-decay – again – there is no prediction from real GUT models – e.g. it is not true that dim.5 operators are challenged by the SK limit.. they are too model dependent (btw dim5 does not give p->e+pi !) and thus there is no need to invoke extra dimensions or Split-SUSY or string models, where – again – there is no prediction.

    DM – we all know there are many candidates, but a solid evidence is already there (DAMA – incompatible with the WIMP picture – waiting to be confirmed whether it is really DM). Similarly for other excesses like ATIC… Would have been nice to have those new evidences put in perspective.

    So in any topic I look I am not satisfied.. what can I say.

    Yes, probably I am also not satisfied with the “conventional wisdom”…

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