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| Breakthrough Prize Trophy. [Image: Breakthrough Prize] |
Interest in supergravity arose in the 1970s when physicists began to search for a theory of everything that would combine all four known fundamental forces to one. By then, string theory had been shown to require supersymmetry, a hypothetical new symmetry which implies that all the already known particles have – so far undiscovered – partner particles. Supersymmetry, however, initially only worked for the three non-gravitational forces, that is the electromagnetic force and the strong and weak nuclear forces. With supergravity, gravity could be included too, thereby bringing physicists one step closer to their goal of unifying all the interactions.
In supergravity, the gravitational interaction is associated with a messenger particle – the graviton – and this graviton has a supersymmetric partner particle called the “gravitino”. There are several types of supergravitational theories, because there are different ways of realizing the symmetry. Supergravity in the context of string theory always requires additional dimensions of space, which have not been seen. The gravitational theory one obtains this way is also not the same as Einstein’s General Relativity, because one gets additional fields that can be difficult to bring into agreement with observation. (For more about the problems with string theory, please watch my video.)
To date, we have no evidence that supergravity is a correct description of nature. Supergravity may one day become useful to calculate properties of certain materials, but so far this research direction has not led to much.
The works by Ferrera, Freedman, and van Nieuwenhuizen have arguably been influential, if by influential you mean that papers have been written about it. Supergravity and supersymmetry are mathematically very fertile ideas. They lend themselves to calculations that otherwise would not be possible and that is how, in the past four decades, physicists have successfully built a beautiful, supersymmetric, math-castle on nothing but thin air.
Awarding a scientific prize, especially one accompanied by so much publicity, for an idea that has no evidence speaking for it, sends the message that in the foundations of physics contact to observation is no longer relevant. If you want to be successful in my research area, it seems, what matters is that a large number of people follow your footsteps, not that your work is useful to explain natural phenomena. This Special Prize doesn’t only signal to the public that the foundations of physics are no longer part of science, it also discourages people in the field from taking on the hard questions. Congratulations.
Update Aug 7th: Corrected the first paragraph. The earlier version incorrectly stated that each of the recipients gets $3 million.
I agree so much. Nice article, Sabine!
ReplyDeletePrizes in Science are fine, but prizes like this and others can often create unfortunate imbalances in the scientific process. Now these people gain lots of pedigree for something that hasn't been proven at all. For many people, they see the prizes but not the work. Even scientists get blinded by titles, journals and positions (prizes).
Especially bad with this prize, is that it is given to a small niche within physics which in many ways establishes a paradigm over others.
The true valuable science is the one that creates something fundamentally new. Through history, the real breakthroughs have seldom gained attention and fame in its contemporary time, but rather ridicule and opposition from the protectors of the old wisdom.
Good theory is usually about correcting the fundamental errors of the past, and not so much implementing errors in an expanding picture of complexity. We have 4 fundamental forces, and that means that the theories are fundamentally wrong, from an axiomatic point of view.
It is simple biology: the protectors of the old wisdom are just protecting their territory/feeding ground.
Delete"...physicists have successfully built a beautiful, supersymmetric, math-castle on nothing but thin air." Wonderful imagery! I can see someone's baroque, geometric creation floating in the clouds.
ReplyDeleteI welcome the prize for the three genius in physics for their hard work in fundamental physics. This will definitely will ignite the healthy competition between deep space researchers. Now the problem is their theory is lagging the proof.Unfotunately this field of space research is done from the very beginning without proof on hand But said with their theoretical experience with assumption and predictions with good faith.And because they don't have the proper instruments not readily available with them to prove.Under these circumstances it is the duty of the future generations to find out some suitable instruments and prove the theory as correct. Anyway time will take it's owntime in these cases.Thanks for the three Musketeers for thier bold theory given as gift to prove for the younger generation
ReplyDeleteThank You Sabine.
"gift to prove for the younger generation". The gift of epicycles. Thank you for that.
Deletevery good. And the model of the proton as the vortex of vacuum is just great.
ReplyDeleteNot really competent to comment on the supergravity itself, sa I wonder if the situation here is similar to mirror symmetry. The latter generated a lot of mathematics and was variously recognized through prizes and career advancements of the contributors, even though, as far as I understand, the relevance of the theory to physics is quite limited.
ReplyDeletePrize, Money and Congratulations for Abstraction
ReplyDelete#
Until we don't see the concrete object of Supergravity
'' the Emperor is nude'' . . . but . . .
. . . but . . . . somebody says:
''Black hole'' is object for Supergravity . . . ?!
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Looking at the state of affairs, between astonished and dejected, I would like to pose a couple of questions to everyone:
ReplyDelete1. Where would a solution be coming from and how would it look like? (solution meaning anything that would bring mainstream fundamental physics back to the realm of sound, testable, accountable, no-bullshit, sciences).
2. Is this hapening in the foreseeable future?
The decision to award the Breakthrough Prize in Fundamental Physics (BPFP) to researchers in Super-Gravity / Supersymmetry (and not, say, to experimental breakthroughs, for instance the latest entanglement experiments, or several others I can think of) is without doubt related, if perhaps not causally connected, to the composition of the Selection Committee. Committee members are eminent, even famous, researchers, all Breakthrough winners themselves. Here are a few of them (leaving out the Higgs and LIGO contributors), in alphabetical order, with brief annotations about their research focus and achievements:
ReplyDeleteNima Arkani-Hamed, Winner BPFP 2012, “proposal of large extra dimensions, new theories for the Higgs boson, novel realizations of supersymmetry, theories for dark matter, and the exploration of new mathematical structures in gauge theory scattering amplitudes.”
Michael B. Green, Winner BPFP 2012: His “work kindled the ‘first superstring revolution,’ which led to an explosion of interest in this novel approach to quantum gravity and the unification of the forces.”
Alan Guth, Winner BPFP 2012: “For the invention of inflationary cosmology.”
Maxim Kontsevich, Winner BPFP 2012: His “work straddles the interface of physics and math. Much of it has been in string theory, in which the familiar particles and forces of physics are described in terms of the shapes and vibrations of incredibly tiny ‘strings’.”
Andrei Linde, Winner BPFP 2012: “For the development of inflationary cosmology, including the theories of new inflation, eternal chaotic inflation, and the inflationary Multiverse, and for contributing to the development of vacuum stabilization mechanisms in string theory.”
Alexander Polyakov, Winner BPFP 2013: “For his many discoveries in field theory and string theory, including the conformal bootstrap, magnetic monopoles, instantons, confinement/deconfinement, the quantization of strings in noncritical dimensions, gauge/string duality, and many others.”
John H. Schwarz, Winner BPFP 2014: “worked with Michael Green [see above] to develop superstring theory.”
Nathan Seiberg, Winner BPFP 2012: “For major contributions to our understanding of quantum field theory and string theory. His exact analysis of supersymmetric quantum field theories led to new and deep insights about their dynamics.”
Ashoke Sen, Winner BPFP 2012: “For uncovering striking evidence of strong-weak duality in certain supersymmetric string theories.”
Andrew Strominger, Winner BPFP 2017: “For transformative advances in quantum field theory, string theory, and quantum gravity.”
Cumrun Vafa, Winner BPFP 2017: “For transformative advances in quantum field theory, string theory, and quantum gravity.”
Mentioning these judges does not mean that the 2020 prize was not deserved by F., F., and Von N., or that the selection was predictable because of sympathetic affinities, but the choice of winners seems to reflect what Yuri Milner, cofounder of the prize, has emphasized as most important for BPFP: they are “the most profound and beautiful creations.” (please read about “gravitons” and “gravitinos” and more hypothetical but pretty stuff here: https://breakthroughprize.org/News/53)
The Breakthrough Prize
Delete/ Motto: think mathematecal - and they will be /
Prizes:
for extra dimensions, supersymmetries,
dark matter, quantum gravity , string theories,
supersymmetric string theories,
multiverse, inflationary cosmology,
for trying to discovery magnetic monopoles,
for our understanding quantum field theory,
for “the most profound and beautiful creations.”
(please read about “gravitons” and “gravitinos” )
and more hypothetical but pretty stuff . . . .
Reality?
No observation and therefore many authors recieved
prizes for one and the same abstract math subject.
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Thanks for this succinct summary. Unfortunate that we seem to be continuing the age of anti-empiricism. Plato is happy. Aristotle is rolling in his grave.
ReplyDeleteAlso muss auf Kant zuruckgegangen werden!
DeleteLet me see if I can illuminate a bit of this. Just what is supersymmetry? Before it is condemned and reduced to rubbish I think people need to have some idea of just what it is.
ReplyDeleteI will appeal to some standard quantum mechanics. In particular we have the boson operators a and a^† and a standard rule is that a|n) = √n|n-1) and a^†|n) = √(n+1)|n+1). I have to use bra and ket notion ( | and | ) because blogs do not like carrot symbols. It is not hard so see that a^†a|n) = n|n) and this defines the Hamiltonian H = ħωa^†a. The Hamiltonian is really ½ħω(a^†a + aa†) and the commutator results in factor of ½ from the unit commutator, and is what gives the zero point energy or vacuum energy. Boson operators obey a commutation rule [a, a^†] = 1 We also have the fermion operators b^† and b these obey and anticommutation rule {b^†, b} = 1. Also the Pauli exclusion principle gives b^2 = (b^†)^2 = 0, which is a topological principle of boundary of boundary is zero.
Now let me consider the operator Q = a^†b, which removes a fermion state and replaces it with a boson. Similarly we then have Q^† = b^†a that removes a boson and replaces it with a fermion. Now compute the anti-commutator
{Q^†, Q} = Q^†Q + QQ^† = b^†aa^†b + a^†bb^†a
I can pass the a and b operators passed each other and so
{Q^†, Q} = b^†baa^† + bb^†a^†a = {b^†, b}a^†a + b^†b[a, a^†],
which equals the Hamiltonian for the boson field times 1 due to the anticommutator and so we have
{Q^†, Q} = H = a^†a
Well this is a neat result, which says that if we toggle between a fermion and boson state we get a time translation, where the Hamiltonian is the generator of time translations. The two fermion and boson states are doublets of supersymmetric pairs. This with further study and work is generalized to a case where
{Q^†, Q} = iσ^μp_μ,
which tells us that a transformation between bosons and fermions so they anticommute to define a Lorentz boost with the momentum-energy generator p_μ. I have suppressed a lot of spinor indices and stuff. It must be pointed out that in natural units this anti-commutator has units of inverse length ℓ^{-1}
This is basic supersymmetry and there is tons more to think about, but I am going to skip to supergravity. Let's think of the graviton, the putative quantum unit of a gravitational wave, as an entanglement between two spin 1 bosons. This is what Berg and Dixon do, and this has a certain economy. This is because gravitational waves have two helicity states, or two polarizations, and if we think of the graviton as an entanglement between two gauge bosons in a colorless or chargeless configuration. So we can write G = aa and G^† = a^†a^† as graviton operators. These gauge bosons in this SUSY picture have their corresponding fermion with operators b and b^†. Let us now do the same thing as above with Gb^† = aab^† and G^†b = a^†a^†b. Now
{Gb^†, G^†b} = aaa^†a^†b^†b + a^†a^†aabb^†
= aa^†(aa^† + 1) b^†b + a^†a(a^†a – 1)bb^†
= (a^†aa^†a + terms linear in aa^†) {b^†, b}
where the anti-commutator is one and there is this a^†aa^†a with dimension ℓ^{-2} and terms with dimension ℓ^{-1}. This is now a curvature and a translation. This should not be too surprising because a gravitation Lagrangian is the Ricci curvature R plus quantum corrections of the form kR^{αβμν}R_{αβμν} that in field components is going to appear as G^†G. The standard Ricci term can be seen to be a quartic term of fermions. See Feynman and Weinberg's little tribute book to Dirac for some of this. This means we have particles on the more classical-like solution given by fermions, which notoriously dislike being in the same state, while the quantum corrections are given by bosons! That quartic term of fermions is similar to the Thirring fermion that is S-dual to the Sine-Gordon equation for a classical soliton.
Continued. So there is something very deep here, and the lesson is that transformations between quantum statistics is correlated with spacetime symmetry, and entanglements of YM particles as a graviton has very deep structure with transformations between fermions and bosons.I want to get to where problems might lie. I am trying to distill things down to certain essentials without all the mathematical filigree so common in physics literature.
ReplyDeleteBefore then consider my operators Gb^† and G^†b. These are for the Rarita-Schwinger field and corresponds to the gravitino. This is a spin 3/2 particle. It obeys an equation similar to the Dirac equation for spin ½ fields. The Ω baryon is a Rarita-Schwinger particle, but it turns out to be composite with spin ½ quarks. So this is not a fundamental. So far no fundamental RS field or particle has been found. Yet Gb^† = aab^† can be thought of as replacing a spin 1 field, or operators that lower such a field, in an entanglement and replacing it with a spin ½ particle. We might think of the gravitational action as a quartic term in fermions (Feynman and Weinberg above), say thinking of the spin 1 particle as built from fermions, where we in effect remove one of the fermions. Finkelstein wrote a paper titled Ω where he considered the world as composite from fermion fields.
This appears to be a topology changing operation. Fermions with b^2 = (b^†)^2 = 0 mean we have a rule “boundary of a boundary is zero.” Apply a fermion operator twice and you get zero, which physically means the fermion can only exist in one state. Yet the Ricci curvature as a quartic term in fermions means we can violate this. Clearly there is condensate physics here, similar to superconductivity. So pulling out a fermion, or equivalently removing a boson (maybe composite of fermions) and replacing it with a fermion breaks what might be called Cooper pairs and changes topology. There is only one arena where this can happen without blasting physics to pieces and that is on a 2-dimensional surface with anyons. The YM fields a and a^† are gauge-like fields for nonabelian anyons. In gravitation there is only one arena where this can occur; it is on the horizon or stretched horizon of a black hole. That this occurs in higher dimensions is a manifestation of holography.
Now to get to problems here. The LHC has found nothing of SUSY partners of known particles. This is a big difficulty. The argument that Kane and others made was that with the elementary {Q^†, Q} = H.and the Hamiltonian as the mass states, then symmetry breaking of SUSY would be a weak field that splits the degeneracy of these masses, similar to Zeeman splitting. The earliest ideas had SUSY partners of particles with 10GeV masses. The Tevatron and LEP failed to find them. So work the phenomenology some more, keeping the Higgs mass “moderate” so the quartic potential of the Higgs field does not send it to the Planck mass. The then proposed multi-100GeV masses of gluinos and neutralinos were not found. There is some hope that longer LHC runs might bear these out, but the problem is that hope can turn into hopium. Will another collider bear fruit for SUSY? It is not impossible, but it means there is a lot of strange “tuning” of the Higgs, and if masses are too high the Higgs field “explodes.”
So why is SUSY failing us? It turns out the total Hamilonian for SUSY is zero. Symmetry breaking raises the energy of the SUSY so H > 0. Yet we have some evidence for inflation, where the vacuum energy was huge, and currently the cosmological constant is small but nonzero. So inflation would have violently broken SUSY, and it is not clear whether SUSY recovered partial symmetry at the end with reheating. Think of water in the liquid state at temperatures far below freezing; without nucleation particles the water can't solidify. Something similar may have occurred here. We may have with particle physics to say adieu SUSY.
A little more: What about supergravity? Without going into great depth, I have commented on how the de Sitter vacuum may have a correspondence with the anti-de Sitter vacuum. This may serve to “protect” the SUSY sector involved with gravity. My simple argument above suggests that without SUSY there is no quantum gravity. With nonabelian anyons there may emerge a form of supersymmetry (http://math.ucr.edu/home/baez/qg-winter2005/group.pdf), and this may occur with fields on the stretched horizon of a black hole.
ReplyDeleteThank you, Lawrence Crowell, for so clearly making Sabine Hossenfelder's point.
DeleteMy hope here is this undergraduate level description of supersymmetry will give some idea of what it is about. Ferrara, Freedman and Nieuwenhuizen developed supergravity with a lot more robust machinery, Grassmann numbers, superfields, supermanifolds etc, and I avoided those things.
DeleteSupersymmetry was developed to circumvent the obstruction found by Coleman and Mandula that prevented unification of gauge fields with gravitation. This BTW is one problem I see with Lisi's project. There is no way to get internal symmetries of gauge fields to work with the external symmetry of gravitation. However, the supersymmetry result I wrote above can be made covariant with a gauge field as
{Q^†, Q} = iσ^μ(p_μ - igA_μ),
for A_μ a gauge potential and g the color or charge that in the case of QED g = e/ħ. Now we can do work with quantum Kaluza Klein theories and this opens the door for quantum gravitation. There is no other way we can pull the reins over the obstructing horns of the Coleman-Mandula theorem. This is one reason so many physicists say things like supersymmetry "must be correct."
I should have been a bit more careful in one statement. I said the gravitino makes quantum gravity possible. It really is that the gravitino is a necessary condition for q-gravity, but it is not sufficient, at least as far as I know.
It is an empirical fact that SUSY has failed to appear in particle physics experiments. The problem with going to the FCC to find SUSY is that a high TeV mass superpartner of light ordinary particles is difficult to model with the Higgs mechanism. The supersymmetric Higgs theory has more massive fields, and there are charged and chiral forms of Higgs particles etc. But getting the detailed balance to work is really tough. This is even if we are guided by the theoretical result that SUSY makes the running parameters of gauge fields converge in a solution of the Hierarchy Problem. As I indicate, there may be cosmological reasons SUSY has failed, and it may not appear (symmetry recovery etc) until you get to GUT or quantum gravitation energy.
Supersymmetry is not dead though. It has been seen as emergent in MeV scale nuclear physics. It also may manifest itself with nonabelian anyons in solid state systems such as graphene, and now there is borene. Borene are similar sheets of boron that may have interesting properties. I think there may be emergent SUSY there, and this could point to SUSY in the holography of black holes. Also with eLISA, and maybe with LIGO we may get signatures of gravitons, which might be correlated with solid state physics work.
You introduce the possibility that Supersymmetry might be emergent from condensed matter. If this is now permissible, why isn’t the polariton conceivable as the supersymmetric boson partner of the electron? Condensation can increase polariton mass to any level to meet the SUSY high mass requirement.
DeleteThe polariton is similar to a SUSY partner, but it does not have the same quantum numbers outside of spin. This does make an interesting point. Supersymmetry is a relationship between certain quantum properties and spacetime. Similarly there are now possible relationships between entanglements and spacetime, and further that QM and GR are really the same thing just manifested in different ways. SUSY might just be one facet of that.
DeleteThe gravitational theory one obtains this way is also not the same as Einstein’s General Relativity, because one gets additional fields that can be difficult to bring into agreement with observation
ReplyDeleteYes, but the fact that low-energy General Relativity can be obtained from gravitons alone is remarkable, and has been so since Feynman first started suggesting this back in the 1960s.
You don't get such a remarkable result without there being some truth in nature behind it.
Supergravity in the context of string theory always requires additional dimensions of space, which have not been seen.
Because the incompetent humans can't build an experiment capable of detecting such things. In any case, the idea that the additional dimensions are just tiny shrunken versions of 3d-space is misleading - they are dimensions in Hilbert Space not the common 3D Space we experience
Supersymmetry is almost certainly true for our universe, and if the humans had the guts to build a 500 tev detector they would be able to see that.
I have no idea what makes you think that a 500 TeV "detector" (presumably you meant collider) would help you see supersymmetry. There is no reason to think this should be the case. Your comment doesn't seem to be very well informed.
DeleteNEWS 06 August 2019
ReplyDeleteSpeculative ‘supergravity’ theory wins US$3-million prize
Three physicists honoured for theory that has been hugely influential — but might not be a good description of reality.
https://www.nature.com/articles/d41586-019-02397-8
It seeems this "prize" is about a group of high-rollers placing a very large bet on something they think will pan out. And that's what Silicon Valley guys like Brin and Zuckerberg love to do. Because based on their own past histories, they believe they have the charm, and know how to pick winners.
ReplyDeletejim_h
DeleteI suspect that what you say is correct. They're placing a bet on ideas and hope that in the future they'll be admired for being ahead. Unfortunately it doesn't seem to have occurred to them that just counting how many people like an idea isn't a reliable indicator for it being a good description of nature.
But of course for Brin and Zuckerberg, "counting how many people like an idea" is how their businesses (Google and Facebook) became hugely profitable. They rank and promote content based on back links, mentions, 'likes' and 'shares'. No doubt they have the social media statistics for supergravity as compared to rival ideas.
DeleteThe group that funds this type of "research" sound a lot like FXQi.
ReplyDeleteFXQi funds your area of research as well. Yes?
What is the point of this post?
There is no point.
You heard it here first:
ReplyDeleteLater this year, in 2020 at the latest, Dr. Sabine H. will be awarded the Cassandra Prize, and the prize quotation will say something like: “For warning the physics community not to enter the cul-de-sac where so many of their brethren have already been lost in math.”
Theoretical physics has become a genre of fiction (cf. Lawrence's comment above). Fictions that depend on other other fictions presumed to be true without any doubt. This genre of fiction of course has proven itself to produce useful and, to some, "truthful" outputs (The Standard Model, General Relativity, etc.). But the space of fictions that is theoretical physics is becoming a rather large space to explore, almost like a "multiverse".
ReplyDeleteBreakthrough Prize in Fundamental Physics
ReplyDeletePrize awarded for . . . . . string theories , inflationary cosmology,
for advances in quantum field theory, quantum gravity,
for the observation of gravitational waves, supergravity,
for the discovery of Hawking radiation, multiverse,
for dark matter , . . . . . .
https://en.wikipedia.org/wiki/Breakthrough_Prize_in_Fundamental_Physics
=============
A very expressive example how billionaires, and very rich people in general, influences the world primarily negative.
ReplyDeleteIn the surroundings of such people, there counts only one opinion: that from the boss.
So, prizes of that kind are harmful and misleading the whole society - not only some happy mainstream-scientists.
As Thucydides put it, "The rich do all they can and the poor do all that they must." Sort of goes with the saying those who have the gold make the rules.
DeleteI would not besmirch Yuri Miller for this particularly. At least he is rewarding some measure of excellence. Compare this to the Koch brother in the US who spend millions on funding fake science meant to deflect climate science results they find, as Gore put it, inconvenient.
There is no consideration about "good rich people" and "bad rich people" if we stick to democracy. If somebody has much more influence than a big minority or even majority, something went wrong.
DeleteTo say: "This rich guy make good things since he has the same view as I." is radically undemocratic and tremendous antiquated.
Billionaire gives money and can have influences the world
ReplyDeleteNot many (a singel ) can decline the award(s) as Grigori Perelman did
when he rejected the more prestije Fields Medal and Millennium Prize
https://en.wikipedia.org/wiki/Grigori_Perelman
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"Nature" has published a similarly skeptical response, with a special shout out to Sabine regarding the failure to detect supersymmetry at the LHC.
ReplyDeleteAsk yourself, why string theory keep getting the fund before anyone else. You can say its crap because shouldnt, or the theory is fantasy etc. whatever. The fact is its still getting the fund and support.
ReplyDeleteBeware of billionaires bearing gifts.
ReplyDeleteBeware of billionaires bearing FREE gifts.
DeleteEloquently stated, Sabine! Thank you.
ReplyDeleteBee, do you think Abhay Ahsketar, Smolin, Rovelli, et al, should also be given Breakthrough Prize in Fundamental Physics, as LQG and LQC is very important
ReplyDeleteNo, they should not be given a prize for having invented a theory that has no known relation to reality either.
Deletei think one reason for the award is that Sugra was fruitful and influential, so since that applies to Sugra, doesn't it also apply to LQG/LQC?
DeleteYes, but I am saying neither has any known relation to observations, hence neither should have gotten a scientific award. The idea that Thor throws lightning bolts was also fruitful and influential.
DeleteBee,
Deletewhat do you think about all the past winners of the Breakthrough Prize in fundamental physics, and New Horizons in Physics Prize, from Ed Witten to Joseph Polchinski, Juan Maldacena, etc nearly all of whom worked on string theory and which has not have any known relation to observations?
Neo,
DeleteIt's not right that string theory has no known relation to observation, that's grossly oversimplifying the situation. It is arguably related to the theories we use to describe observations, and thereby also related to observations.
You can't throw all of these people in the same pot. Witten and Arkani-Hamed, eg, have done/do some actual physics research. This is to say, you are asking for a simple answer where there isn't one. Everybody is different.
the Breakthrough Prize in fundamental physics also rewards purely theoretical research in physics, without any known relation to observations, perhaps that the insights could one day better explain known relations to observations. so if you define a scientific award to relate known relations to observation, it's not a scientific award.
Deletedo you have any objections to giving this award based solely on a assessment of theoretical research like supergravity? maybe calling it a science award is incorrect, but an award for theoretical insights that may one day bear fruit.
Yes, that's awesome, let's call it "an award for theoretical insights that may one day bear fruit (or not)".
Deletehttps://www.xkcd.com/2186/ I suppose this is close enough a topic and recent. This is a funny take on dark matter.
ReplyDeleteNeo, I do not know what nice words accompanied the awarding of the prize to Witten (say), nor just how many of his string theory papers (or those which directly cite them) explore applications beyond fundamental physics (however defined), but string theory has found applications in other parts of physics (e.g. condensed matter physics). The following analogy is weak, but the theoretical work of quantum pioneers (e.g. Dirac) later found wonderful applications in non-fundamental parts of science, e.g. chemistry.
ReplyDeleteThat alas is yet another in a very long list of fruitless conjectures.
Deletehttps://www.math.columbia.edu/~woit/wordpress/?p=4053
-drl
that's fine.
Deletesabine has some issue with awarding the breakthrough prize to SuGra on the grounds there's no evidence for SUSY or Sugra, but that's what the nobel prize in physics is for.
LQG has found application to loop cosmology so it is attempting to be real world science.
neo,
DeleteYou could likewise say that string theory has "found application to" string cosmology and that would be equally wrong. These are phenomenological models. They are not derived from the theory. And if you want to argue that someone should hand out a prize for making an effort to tie quantum gravity to observation, by all means, go ahead. I am totally in favor of that.
Thanks for the link, drl. I note that a) Peter is clear that this (high temperature superconductivity, and condensed matter physics) is a field he is unfamiliar with, b) the comments seems to be about superconductivity (and quark-gluon plasmas), rather than the broader field, and c) it's dated 2011.
DeleteIt's also a field I am unfamiliar with, and I cannot tell from reading several apparently relevant review articles I found how biased (or not) they are.
well sabine, remember how many decades it took for general relativy prediction of gravitational waves for technology to advance to confirm it?
Deleteor the time it took from peter higgs to propose the higgs field and boson, to its conformation from lhc, before finally being award the nobel prize in physics?
what kind of prize should be awarded to theoretical ideas in physics for which there's no technology, nor near term future technology to verify it, and what criteria should be used?
MOND has no experimental way to be confirmed.
Neo,
DeleteYou are not following. Gravitational waves are a prediction of a well-confirmed theory. The Higgs-boson is necessary for the standard model to work. Susy/sugra are utterly superfluous. They are inventions. There is no reason to think they are correct.
"what kind of prize should be awarded to theoretical ideas in physics for which there's no technology, nor near term future technology to verify it, and what criteria should be used?"
Maybe we shouldn't award prizes for it?
"MOND has no experimental way to be confirmed."
MOND has been experimentally confirmed many times and if anyone deserves a prize it's Milgrom.
stephen hawking did win the 2012 breakthough prize, but there's no confirmation of hawking radiation or bh entropy. clearly important theoretical result.
Deletei'm not aware of MOND being directly confirmed by experiment, if it were, why are physicists still searching for dark matter?
Neo,
DeleteHawking radiation, too, is a prediction based entirely on well-confirmed theories. There's nothing invented about it.
MOND is a phenomenological model and its predictions have held up over time, while LCDM simulations have been continously adapted to cope with new evidence. MOND isn't necessarily in conflict with dark matter (I have explained this elsewhere and don't have time to repeat this), but really this isn't the point. The point is that Milgrom did exactly what you expect scientists to do: He identified a pattern in the data, generalized it, made predictions, and those predictions work. It is beyond me why this receives so little attention while fairy tales like sugra make headlines.
maybe Milgrom McGaugh et al should win the 2020 breakthrough prize.
Deleteneo, Sabine: MOND is not a very good example ... as theory it's dead on arrival (incompatible with Special Relativity), and problematic as phenomenology (range of applicability seems rather arbitrary, for example).
DeleteIn astronomy, phenomenological models (or relationships) abound - e.g. the Fundamental Plane (galaxies), SMBH-galaxy mass relationship - yet no one would consider giving any Breakthrough prizes to any of the authors of these. Sometimes these empirical relationships pan out - e.g. the Hubble relationship - and become firmly part of well-established physics, but other times they don't (e.g. the Hubble sequence, or tuning fork, on galaxy morphology).
It's a non-relativistic limit. Newton had to start somewhere too.
DeleteYesterday Sergio Ferrara has been interviewed on italian Radio Uno. It was just few minutes, he has been asked to explain what supergravity is. To be honest, not knowing anything about the subject one could think that it was talking about an "acknowledged" theory. He also said that the theory led to a lot of experiments. But at the end he joked saying that the Higgs boson took 60 years to be found, and being his theory 40 years old he still has another 20 to find the proof.
ReplyDeletePS: he also has "no idea" on what to do with the money :-)
I cannot say this often enough: The Higgs boson (or something with a similar effect) was *necessary* to make the standard model work. Supersymmetry/supergravity is entirely unnecessary. There no reason to think it'll ever be discovered.
DeleteIt should be pointed out that P. van N. has be awarded not this 1 prize, but actually 4 of them for his ruled-out idea - this one in 2019, The Dirac Medal from Trieste (very prestigious) in 1993, the Dannie Heineman prize from APS in 2006, and the Majorana Medal from Erice in 2016. You could call that the Grand Slam of non-Nobel physics prizes. Maybe this business of science by prizes and press releases is the actual problem.
ReplyDelete-drl
There appears to be some confusion over string theory and supergravity. Supergravity is a supersymmetric form of general relativity. String theory is the hypothesis fields are parameterized along a chord rather than associated with a point or point-like particle. The supersymmetric form of string theory incorporates supergravity in the TypeII versions and heterotic forms of the string. The string eliminates vertex problems.
ReplyDeleteSupersymmetry because it circumvents the Coleman-Mandula "no-go" obstruction strikes me as a reasonable bet in the long run. With extensions to gravitation, again it seems reasonable. String theory is more problematic, but I keep it in my intellectual toolbox. I also keep LQG and dynamic triangulation in a corner of my mind as well.
Supergravity is a supersymmetric form of general relativity.
DeleteString theory is the hypothesis fields
The supersymmetric form of string theory incorporates supergravity
/ Lawrence Crowell 5:58 PM, August 08, 2019 /
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Supergravity ---> Supersymmetric ---> String theory ----> Supergravity
/ Minotaur's labyrinth /
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I think a conclusive negative evidence of super-symmetry is here the real winner. As a non-expert I recall that Edward Witten proved the positive energy (mass) theorem in general relativity under the assumption of super-symmetry. Therefore, if super-symmetry does not exist, negative masses might exist, in accordance with the negative energy density of a static Newtonian gravitational field. Einstein said:"God is subtle but not malicious", as a God with 11 dimensions would be.
ReplyDeleteWitten demonstrated the anti-commutator {Q-bar, Q} = -iσ^μ∂_μ with the momentum operator p_μ = -i∂_μ for timelike translation gives particle masses that are positive. In a supergravity setting this is consistent with the positive energy conditions of Hawking and Penrose.
DeleteE. Witten, "A new proof of the positive energy theorem", Com. Math. Phys. 80, 381 (1981)
Hawking et al showed that this also works with anti-de Sitter (AdS) spacetimes, where though the vacuum energy is negative the particle spectrum is with positive mass. Also for supersymmetry a positive vacuum energy breaks supersymmetry, which means supersymmetry exists in AdS in an unbroken phase, while in de Sitter spacetimes it is broken. I think one possible piece of evidence for inflation is that it was a time when the dS vacuum was huge and this may be completely broken SUSY so it does not recover.
The holographic principle tells us that fields on the two dimensional horizon of a black hole, with coordinates (θ, φ) at radius r = 2m, defines fields in 3 dimensions. These coordinates are Poincare dual to the coordinate (t, r) and this has structure dual to the holographic screen similar to a Haldane chain. This means the quantum phase of states are hyperbolic, but with two states separated by a light cone. The dS spacetime is the continuous hyperbolic sheet, thought with a p = ±∞ boundary, and there are two AdS spacetimes bounded by the past and future cones. The question is why is so much of our theories “comfortable” in AdS, but not so in dS, and is there a duality of some sort so SuGra states in the AdS are topologically protected so they hold in the dS? The spacetime we observe is at least approximately dS.
Prize winner in 2029:
ReplyDeleteGravity is a Go 2 program.
Bee,
ReplyDeletewhich previous Breakthrough Prize in Fundamental Physics award winners do you agree with and which ones you don't?
many have been given out to string theory and GUT's and inflation.
list here
https://en.wikipedia.org/wiki/Breakthrough_Prize_in_Fundamental_Physics
if the list is too long, what do you think in a sentence or so, of the previous winners of Breakthrough Prize in Fundamental Physics award winners since obviously you have issues with Sugra in 2019
Breakthrough Prize
ReplyDeleteFor the seventh year and renown as the “Oscars of Science,”
the Breakthrough Prize will recognize the world’s top scientists.
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“When we think of the great works of the human imagination,
we often mean art, music and literature,” said Yuri Milner,
one of the founders of the Breakthrough Prize.
“But some of the most profound and beautiful creations are
those of scientists. Supergravity has inspired physicists for decades
and may contain deep truths about the nature of reality.”
https://breakthroughprize.org/News/53
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Science is not ''imagination''
If supergravity as a mathematical imagination awarded Breakthrough Prize
then it is ''Oscars'' scientific Fiction prize.
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Your concerns reach mainstream media.
ReplyDeletehttps://www.sueddeutsche.de/wissen/physik-supergravitation-breakthrough-1.4558402
To speak about ''Gravity -- Supergravity'' at first is needed
ReplyDeleteto understand Quantum Gravity.
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Quantum Gravity is QT + GRT
QT (Planck microworld)
GRT (Sun-masses-macroworld )
To unite them,
the macroworld of gravity must be examine
on the microlevel of graviton: QT + Gravitons-masses.
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The microscopic origin of thermodynamics is unknown.
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Selection Committee
ReplyDeleteSelection Committee for the Breakthrough Prize in Fundamental
Physics and the New Horizons Prize in Fundamental Physics:
https://breakthroughprize.org/Committee/1
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Did ''Selection Committee'' give the prize to themselves ?
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Sabine, about GR being local..
ReplyDeleteThis is actually sort of a sticky point. To get a genuine conservation law in the sense of "no jumps" - that is, if something disappears from a volume, then it had to go through the surface of the volume - then it must be expressible as the ordinary divergence of something being = 0, not a covariant divergence. As far as I know (from e.g. Fock, Weyl, Dirac) this is not possible in GR. So Tmn;n = 0 (covariant derivative of energy tensor) is not a local conservation law. You have to add non-local effects, which means in general you can only write a conservation law in integral form, which brings in ambiguous features. Now, for a vector field (or in general for any exterior form, i.e. a totally antisymmetric tensor) you can convert a covariant divergence into an ordinary one and so write a "no jumps" conservation law. The field under consideration picks up a factor in the square root of the determinant of the metric to some power, which when differentiated cancels out the bad terms coming from the connection coefficients.
Whatever people conclude about energy conservation in GR is colored by this fact. I always thought this was a really important clue as to how to make progress. It seemed to me this was saying something very important about the status of GR as a foundational theory.
Thanks for the post, it's an incredibly interesting topic.
-drl
Einstein's GRT is theory about one (1) single body-mass
Delete(like Sun) and therefore GRT is local phenomena.
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There are billion - billions such local stars gravity
phenomena in the Universe but all their masses
is to small (critical density is about 10^-26 kg/m³)
to allow ''gravity'' be universal-king-law.
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PS the last post was meant for the Quantum Measurement entry. Sorry :)
ReplyDelete-drl