Is String Theory A Waste Of Time?

  1. "But, even if it is completely wrong, basically no theory is a waste of time, as long as it is well developed and researched."

    The problem is that it is not well developed and researched. As said by Nobel laureate P. Anderson this year, string theory is a futile exercise as physics.

    "A lot of times, the journey is more important than the goal, I think."

    Well, perhaps, but anybody agree that Einstein unified field theory was a waste of time. He simply ignored experimental data on favour of a "beatiful" idea and he failed. As often ask Nobel laureate Glasgow, why Einstein few years enedeavor is seen like a failure but 30 years-1000 physicists research in string theory do not?

    "All these extremely intelligent people are sitting around pondering string theory."

    Yes this is another of myths of string theory propaganda. "String theorists are very smart, rest of people is stupid." Still, and this is a really interesting point, no one string theorists have solved or provided solution to some of most difficult open problems of physics, and some of proposed solutions by them are simply stupid. For example, Brian Greene ideas on quantum-classical correspondence were ridiculized last year by Dyson (Nobel laureate).

    I think that your emphasis on theories that are still in a initial stage or still nobody know if are both correct or wrong. However, people is critizing string theory because is wrong.
  2. jcsd
  3. I'm not a string theorist (nor I plan to be :) ), but can you explain why do you think string theory is wrong ? I thought there are no experimental evidance that go either in favor or against strings and that we should wait until the first results of LHC.
  4. Imagine this--

    It is the days before newton. One semi-retarded man writes an elaborate paper saying everything falls up. Another man, named Newton, reads this paper, and says.

    "What a retard! Things fall down!"

    So, Newton writes a paper, which says-

    "No, I have never seen anything ever fall up. In fact, things fall down, except for ballons. Ballons are weird. So, things fall down. Mostly."

    Everyone doesn't believe this, cause it well, sounds stupid, and not thought out. And also, it has one itsy-bitsy exception.

    So, for a while, the world believes everything falls up, because the theory is so elegant and refined.

    Newton is pissed off. He spends months testing his theory, while everyone is calling him a idiot. He drops lead balls. He drops ping-pong balls. Soon, he has created a brilliant set of laws defining things falling down. He calls them gravity.

    Now, imagine if that first man had not written his paper on things falling up. Newton wouldn't of had to prove him wrong, with good evidence. And, the laws of gravity would of not been found. People would of just accepted the fact that things generally fall down, without really understanding why. A great loss to science.
  5. Chronos

    Chronos 10,268
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    String theory is vulnerable, but the concept is sound. I agree it is losing ground, but handwaving objections are objectionable. Don't take that as meaning you are wrong, I just think the right thing to do is to substantiate all objections. You may not arrive at the same conclusion if you think it through. ST is not as weak as it sometimes appears. I have reread Witten's papers a dozen times by now, and he has some very good points. I can't refute them. My gut feeling is ST is wrong, but I have no right to object without a substantive reason.
  6. First i am not claiming that some parts of string theory can be useful in strong force for example. I was claiming that string theory is wrong like a TOE.

    Remember that string theory is, in the words of its more popular practitioners, the Final Theory: the Last True.

    The list of obious failures and experimental incorrections of string theory is so imppresive that one needs more than 100 pages for detailing all the math. A small, non-technical o:), criticism is available at

    The idea string theory has been no tested is wrong. String theory has been always tested and always has failed :yuck: . It was tested in the strong force regime 30 years ago and continue to be tested now. For example, some years ago they claimed a cosmological brane model explaining universe. In a tour of force, Andrei Linde (the same of inflationary theory) showed that the model was wrong and the claimed "explainings" do not fit known experimental data.

    String theory is wrong; it has failed for explaining everything. It has failed for quantize gravity (perturbative series is not well defined and nonperturbative regime is unknown), it cannot explain GR (contrary to popular Witten claims string theory does not predict gravity, really string theory is adapted to previously known gravity), etc.

    String, stwing, M-theory, and all that stuff are a waste of time. Since that their research is based in irrelevant mathematical formalisms and outdated concepts :zzz: . String M-theorists (here and thereafter SMt) are so arrogant that with a superfitial mathematical knowledge of other fields of science, they claim for a Theory Of Everything. The list of outdated concepts and irrelevant mathematical formalisms is greater than number of estimated vacua (-:

    - Usual quantization of the classical bosonic string violates cosmological boundaries. (I wait that SMts will recognize this error before 2050 :-).

    - The spacetime used (CY, G2, etc.) do not account for the non-differential character of stochastic processes. It will be funny like string theorists will attempt to model spacetime-foam noisy contributions to a triple D0-brane collision. I wait to see their faces then!

    - In the usual unitary vectors space of string mathematics the L-product of two elements is not defined. Only in the L-space the relation I+(rs)I+(tu) = I+(ru)delta(st) is defined. No similar product relation exists in the H-space (dimension n) because L-space (dimension nn) is more general. That is, the supposed TOE cannot explain, for instance, Ernst’s work in NMR (that received the Nobel prize) :-)

    - The fixed background S-matrix is, undoubtedly, a funny caricature of real-word processes. There are dozens of well-known papers on the topic and even a new branch of string theory developed!

    - Vector states used in the standard spectral decomposition of strings (branes) are of course valid only in the limit T --> 0. This was known for decades in other fields of science like plasma physics (quark-gluon plasma). Only the last 5 years, after of three decades of totally wrong research and funny claims, SMts fixed this sound error and developed the very recent Dp-branes theory with the (~) operators, which only work in the linear regime. Far from eq. one cannot use the tilde (~) operators due to well-known presence of dynamical bubbles coupling spacetime events. Of course, all this advanced mathematical stuff was/is ignored by leading researchers like Witten, Greene, Vafa, Schwartz, etc. Witten, the great genius, the great theoretician, the new "Einstein", did NONE contribution to recent doubled space Dp-branes theory. In fact, his great mind did not know the problem with the use of standard states because he like other string theorists study the topics just superficially. He is a great string theorist sure :-)

    - String theorists still claim for the derivation of an unitary theory, whereas people in other experimentally proved theories are working with LPS theory in Gelfand triplets. The theorems used are outside of the simple and outdated string mathematics, and one needs a lot of recent mathematical work in rigged spaces and involutive Banach algebra of bounded operators. These non C*-algebras are, of course, ignored by SMTs and their irrelevant TOE. It is impossible to explain recent models for neutral Kaons and its counterparts in higher-flavor-generations from the basic mathematical framework of string, M theory. Concretely the models developed in the last decade by Sudarshan (e.g. generalizing the LOY model) does not fit to string M-theory because are more general.

    - Non-critical string theory is more advanced that usual critical (Witten-Schwartz-Vafa-Greene-etc.) one in fixed backgrounds but again irrelevant for a TOE. The most advanced formulation today in non-critical theory simply use “Lindblad–like” operators (which is only valid if one take the zero limit of the correlation functions for the different vacua) to take into account quantum transitions between different critical string vacua. Moreover, the non-critical string theory has unsolved problems. One can show (with the aid of mathematical methods unknown for SMts and still don't applied to noncritical formulation) that non-critical string theory formulation is just a shadow to more consistent and generalized theories.

    - Etc, etc, etc, etc, etc.

    M-theory is "the best candidate for a theory of everything", sound like that old claim of "all universe is understood from Newton mechanics".

    All of us know how accurate was the claim :biggrin:
    Last edited: Jul 12, 2005
  7. Many string theorists are very arrogant. If your theory permits to you compute nothing you would say this to people. It appears that they want emulate to Einstein ant become smart. But sincerely, no one string theorist has done nothing interesting in physics (in other fields like biology, chemistry or non-linear economoy the contribution of string theorists is easily summarized none). Gross won the Nobel Prize for his work on particle physics and Witten was awarded by his mathematical work. No one string theorist has solved some of most important open problems of theoretical physics: quantum measuring, arrow of time, chaos, quantum gravity, unification, etc.

    As claimed by particle physicist Peter Woit, the only success of string theory has been in mass media. Many people, undergraduate students, other scientists, etc. are very confused with REAL status of string theory.

    For example, in his "popular" Elegant Universe Brian Greene claim that one can explain why there is three spatial extended dimensions from string theory. Why are there 3 instead of 5 or more? Greene explains to his inexpert public that was explained by string theoris (Vafa and others).

    Compare that with recent Witten reply to question:

    NOVA: If these extra dimensions exist, does string theory offer any explanation of why there are apparently three space dimensions larger than the rest?

    Witten: That's a big problem that has to be explained. As of now, string theorists have no explanation of why there are three large dimensions as well as time, and the other dimensions are microscopic. Proposals about that have been all over the map.

    There are dozens of other examples of obvious manipulation of true.

    Is all this lot of false claims, mass media and students manipulation, outdated mathematical research, incorrect hyphotesis, ambiguity (there is no string theory just a program called string theory), incompatibility (some papers claim contrary of others), false propaganda (only 1000 physicists follow this theory and most of smart people and Nobel laureates do not like it) the current fad in theoretical physics?
    Last edited: Jul 13, 2005
  8. String theory proved succesful in that respect - the relation of the scattering amplitudes of resonance states of baryons and mesons to the Regge trajectories.

    The brane model you are refering to is a rather crude one, if I'm not mistaken. There have been significant improvements in that regard, particulary pertaining to the use of anti-de Sitter space coupled with conformal field theory. See for instance:

    It's true that there's no non-pertubative string theory.

    Doesn't massless spin-2 field work?

    How can quantization of strings violate cosmology? Note: A simple method of quantization (which I know of) is to start with a classical string then impose the quantum light-cone gauge and use the Virasoro algebra.

    What's non-differential?
  9. Hurkyl

    Hurkyl 15,998
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    It's false that research into String Theory hasn't produced any results in other fields: not only has it generated a wealth of new mathematical ideas, but these theoretical physicists seem to have a knack for solving tough problems in classical mathematics, number theory in particular.
  10. Hurkyl

    Hurkyl 15,998
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    It seems to me that people are criticizing string theory essentially on the basis that it's work in progress, rather than a finished product.

    That's a rather absurd way of looking at things. When you have an idea, the corresponding full-fledged theory doesn't appear out of thin air, ripe for testing.
  11. string theory is a waste of time

    False!!! The history of physics is there!!! The development of a string theory of ALL aspects of hadrons failed, and the theory was abandoned in favor of the, then new, QCD developed by Gell-Mann. This early failure of string theory is recognized even by string fanatics as Schwartz, who said

    I was referring to J. Khoury, B. A. Ovrut, P. J. Steinhardt and N. Turok. Phys. Rev. D 64, 123522 (2001), what is more modern that your ArXiv link. Lindé did not comment on the paper because was “rude” or “few detailed” still. Simply the computations were completely wrong (even if string theory was correct!!!) and, moreover, the authors introduced lots of assumptions and hidden hypothesis. Moreover in future works, string theorists (arrogant as they are) ignore all failures. Lindé says

    and add

    Of course, Lindé like many of others experts disagree with last above claim. String theory does not work and when it is showed that does not work string theorist ignore the criticism and sent notes to mass media. This make part of string community sociology.

    Linde expresses our belief in a brilliant form

    Cosmologists Kraus called string theory a colossal failure and, if I am now wrong, he is writing a book on the topic that will released this year.

    You are following Feynman’s idea too arbitrarily. Let me focus on details. String action works in 10D and “defines” a perturbative expansion in a fixed background. 1) Gravitons has been not detected, in fact, even gravitational waves are not detected still. 2) The perturbative splitting of metric is incompatible with GR; in fact, GR causality is not supported. 3) If GR was unknown, nobody had substituted the fixed metric in the string by a dynamical one. Therefore, one is forcing ST to compatibility with GR, not deriving the latter from ST. 4) compactification to 4D is done by hand and, moreover, required (ad hoc) for compatibility with usual experimental data not predicted by ST. 5) string theory does not explain astronomical spacetime 6) string spacetime does not account cosmological expansion. 7) The practice in string theory is to assume that spacetime quantum field theory describes the large distance physics. First, a macroscopic background spacetime is chosen by hand, arbitrarily, from among the manifold of possibilities. 8) Etc.

    You are very wrong, just like string theorists. What is the wavefunction of universe, if any?

    Hum, a note for navigators, Polchinski two volumes on string theory is not I call high-level physics. Brian Greene’s research in Calabi-Yaus is not I call sophisticated math.

    In a differential manifold R4 (SR), Calabi-Yau (string theory), G2 (M theory), etc.

    The space [tex]dx[/tex] is

    dx = vdt

    with [tex] v [/tex] the velocity. In general, this is an approximation. The most correct formula is

    [tex]dx = vdt + fdt[/tex]

    with [tex]fdt[/tex] a non-differentiable element. Most of interesting formulas used in many fields (e.g. [tex]Ca^{2+}[/tex] transport in living cells) are empirical (ad hoc). For example, the assumptions of

    \langle f(t) \rangle = 0


    \langle f(t)f(t') \rangle = cte \ \delta (t-t')

    used in white chemical noise.

    In canonical science (many times more sophisticated and advanced that stupid string theory), all of these standard formulas arise from basic topological properties of omega coefficients and non-differential character of spacetime foam.

    I agree, but in other cases, the theories are at least partially useful. The Big bang is not perfect but rationalizes lot of data. From string theory, one can predict or compute nothing in rigor. In fact, all popular claims on string theory are simply wrong. There is a joke in Internet that said that now string theory is a theory without strings, but people ignores this!!!

    Yes, but it has failed in the unification. In fact, ALL string theorists -so excited in the past- now agree that string theory cannot do it and are searching for a new theory that nobody know and is dubbed M theory.

    Fantastic!!! But since string theorists have no idea of nothing complex (many of them still believe in the reductionist approach!!!), their theory is completely outdated. Canonical science is not reductionist, it unifies chemistry with ecology, economy, physics, etc. but still is not a true TOE. The TOE is a myth; it does not exist.

    All macro-predictions of string theory (e.g. Black holes, cosmology, dark matter, etc.) are incorrect or very deficient. In cosmological issues, the discrepancy between theory (string th) and experimental data is far for more than 50 orders of magnitude. Yes you are read ok, 50!!

    Nobody said that string theory was not useful in some mathematical issues. Moreover, there is a popular exaggeration that said that modern math is just string theory math, which is simply stupid. The number of mathematicians working in string theory stuff or similar is really small. People working in other fields has also advanced math without working in string M-theory.

    Of course than no!! This is a typical string argumentation. The theory is permanently open by them!!

    If string theorist claim for a consistent perturbative regime of quantum gravity (e.g. without infinites) then I could say hey nobody has demonstrated absence of infinites at all orders. Then string theorist could claim that theory is open and I agree.

    But if a string theorist claim that universe manifold is aCY or a G2 I said that is wrong and that is independelty of open issues regarding both of those manifolds. If string theorist write the wavefunction for a bosonic string I said that that is wrong if he argues that from string theory he can explain all I said that has no idea of nothing, etc.

    That is I am not claiming that string M-theory is almost good with some obscure points that would be corrected in a future because the research is still open. I am claiming that ALL of current string M-theory is completely wrong for a TOE (or quasy-TOE).

    The problem is that the name string theory has been maintained by marketing purposes. Many people think that string theory now is the same that two or three decades ago, which is completely false. In fact, the history of string theory is a history of succesive failure due that string theorists are unable to achieve a consistent theory.

    I find the next quote that will add to me own collection:

    Last edited: Jul 14, 2005
  12. Tom Mattson

    Tom Mattson 5,526
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    Indeed! And I've just finished pruning several of those handwaving objections out of this thread. Let us have no more talk of personalities, no more blanket charges of arrogance, and no more empty arguments propped up by quotes from famous people. Let's raise the standard here. Arguments against string theory should address the theory itself, not those who work on it or things that people say about it.

    Juan R: I like what you are doing here. You're getting specific. For instance:

    I'd like to see the discussion follow these leads. How can we know that these points are true? Why would the truth of these points mean that string theory is wrong? Let's see more of that sort of thing, let's keep it dispassionate, and let's keep it specific. Otherwise I am going to shut this thread down.
  13. Well, I beleve that this is a forum, and one would open the hand. Of course, one may search strict scientific/mathematical terms in a formal paper, but here i could one day to say that M(atrix) cannot explain a chemical reaction in condensed phase (is mathematically imposible) and, other, i can say that Lubos Motl is a very arrogant guy with no education (I know that his internet style is "you are @#$%t!!").

    People doing mocking of string theory community is doing because string theorist are very arrogant. Each day are proposed dozens of theories/hypotesis. The problem is the "macho-arrogant" attitude of string theorists resumed on string theory is great if you are not working in it a) your are not smart or b) you are stupid and cannot see its "elegance". String theorists are manipulating public, young students (how many students began a PhD in string theory and after leave the field when discover that was ugly?), and public.

    Moreover, they did (and continue to do it) many dishonest actions against other theories/people. For example, it is well-known that Glashow (Nobel Prize for physics) was forced to abandon the university due to his incisive criticism to string "theory".

    Of course, this is just my point.

    Studying them, as it is normal in science!

    This is obvious. E.g. if your TOE cannot explain RMN spectrum of a protein in solution (the relation I+(rs)I+(tu) = I+(ru)delta(st) is not defined for wavefunctions in a Hilbert-Fock space), then your TOE is not complete and people working in other fields is not doing "applied" stuff.

    If string theorists like Schwartz are claiming that string theory is unitary and are searching for an unitary evolutor then i may sday that them have no idea of nothing. There are fields of science that are dozens of times more advanced that string theory but string theorists have no idea of notgin and continue working in outdated stuff.

    This is not so surprising for me. Still many physicists believe (of course incorrectly) that chemistry was reduced to QM. In fact, Witten said that in a recent interview. Why? because Dirac said it! Whow what argument!!!

    Chemists smile of that mith (look some of multiple papers in Foundations of chemistry journal. Murray Gell-Mann (probably the most smart physicists living) has said in the Quark and the Jaguar that, of course, Dirac famous quote was an exageration.

    The question of failure of string theory is joined to string theorists. This is a fact. String theorists do a sect otherwise the scandal around string theory is not seen in other fields of quantum gravity: NC, triangulations, geometrodynamics, LQG (except Smolin and some friends), etc.
  14. Some references would be nice. :smile:

    I am not personally subscribed to APS so I can't view the paper at this time. I will read it as soon as I start my undergraduate courses (via my university's subscription).

    Actions of string theory work in other forms in dimensions other than 10.

    The former can be attributed to lack of technical ability, while the latter is not only a problem that string theory should be concerned about.

    Since standard string theory is not backround independent and hence not complatible with GR to begin with the point is moot.

    T-duality is a very useful mathematical tool. It makes to theories for all intents and purpuses equivalent. If you can show that it is somehow incorrect then that argument would be fatal to string theory.

    How can I be wrong? I merely asked a question, not made a statement.

    I am not familiar with physical chemistry, so you will have to forgive my ignorance as I will ask for some references.
  15. Tom Mattson

    Tom Mattson 5,526
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    You believe wrongly. :smile: Physics Forums is not a place to rant and rave about personalities.

    Please stick to the former, avoid the latter. What Lubos Motl does elsewhere on the internet has no bearing on our policies. And I can promise you that if he were to do that here, he would be warned about it.

    I'm skipping over the next part, because it is exactly the sort of thing I'd like to avoid.

    I mean: Where are the references?

    OK, let's back it up a step or two. I find it difficult to accept this as a valid criticism. I can see how one might argue that the calculation you describe above is just too complicated to do with a theory as supposedly fundamental as string theory. What would you say to that? Are you saying that it is impossible to do such a calculation with string theory, even in principle? If so, then how do you know that?

    Sure you may say it, but what's the reasoning behind your statements?

    I'll say it one more time: This forum is not for the discussing of personalities.
  16. Falling "up"

    The real moral would seem to be: One should be careful who one calls a semi-retard.

    Assuming that “falls” implies acceleration; and, by "up," what actually is intended to be connoted was “outward”; it is now known . . . and well accepted, thanks to the Hubble Space Telescope’s confirmations, that massive Cosmic bodies do “fall up.”

    Newton was also wrong about inertia. The HST indicates that inertia should be a force (counter to gravity); however, its acceleration and elliptical curvature, at anthropic scale, is too minuscule to observe because of the great distance from which it operates.

    Einstein did have the concept of a Cosmological constant right; only, it’s not constant. And, Einstein, also, had the source, and therefore, the direction wrong.

    However, as Einstein well knew, such an adjustment to GR was a structural requisite without the Big Bang. Einstein has the excuse that he couldn’t be aware of later counter-intuitive observations. What excuse do today’s theoretical physicists have?
    Last edited: Jul 16, 2005
  17. I'm sorry, I have no time for providing you detailed references. I am very busy and have no time for searching now the papers, but most of i say is based in an abundant recopilated literature (physics, biology, ecology, physics, etc.) that i cited in several works, preprints, books, etc.

    Check on for papers, non-technical documents, and full lists of references in some time. I believe that my articles on CPS are not available due to closing, but there will be available again in the web above.

    I believe that you can search by yourself the history of failure of string theory and of string force simply in Google (i do not check this).

    Yes, i was refering to "correct" (2, 10) scan of supersymmetric version.

    Well, perhaps "can be". Some people like Dyson agrees that there is no gravitons after all.

    That contrast a bit with usual exagerated claims from string theorists. It is wel-known that Witten claimed in popular press that string theory predicts GR. In a recent Scientific American, B. Greene lists one of main advantages of ST over LQG the existence of well defined classical limit that is GR.

    Therefore, from "string theory unifies QM and GR" you now are broadly admiting that ST is, in fact, incompatible with GR (just as relativist claimed for decades). Well, please explain that to miles of readers of string theory literature or just to editors of popular magazines like New York times or similar.

    Moreover, i believe that you ignores that, in the past, string theorists thought that full background invariance of GR was just a macroscopic approximation and initially they really thought that the split was correct. In fact, the perturbation of classical flat metric was interpreted like the real graviton.

    I was talking about compactification M10 -> R4 x M6.

    Ok. I believe that you do not know about these issues because you ask on it. I think that you believe that there is a wavefunction for the universe, otherwise you would not ask "How can quantization of strings violate cosmology?".
  18. Well perhaps you are right. However, some people in

    focused in stupid personal attack, and Lubos Motl indirectly entered in the convestation with a 'moo'. Curiosly D. Gross (Nobel laureate and one of leaders of string theory said similar stuff that i said. I wonder if Lubos would "moo" to David.)

    I replied above. I think that you have not problem in doing automated search in databases for obtaining papers or preprints. I'm sorry by the inconvenience.

    This is a typical physicists' error. "Chemistry is reduced to physics but is computationally difficult". This is false. I was not talking about computational issues. I was saying that higher levels of matter have new information that cannot be reduced to low levels. The computation of RMN from strings is not a computational problem. The math involved in string theory is not sufficient. just an approximation, because algebra is more complex and above product is not computationally diffcult: it is not defined in string theory based in usual Hilbert space math.

    the relation I+(rs)I+(tu) = I+(ru)delta(st) is not defined for wavefunctions in a Hilbert-Fock space). Therefore you cannot even formally represent a protein like a huge collection of strings, some what like you cannot represent they like a collection of classical particles. It is not about computational difficulty

    Universe is nonunitary, therefore string theory is in the wrong way. Search nonunitary theories used in laboratories of all world. I recomend to you look to Prigogine institute for example and search for his generalization of scattering theory.
    Last edited: Jul 16, 2005
  19. selfAdjoint

    selfAdjoint 7,521
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    Juan, can I jump in here for just one post? Our custom here at PF is that if you make a strong claim (which you have) it is your responsibiolity, not your readers' to come up with the citations, preferably online. So you claim that string theory not only does not explain or predict NMR results but that it cannot, that there is something wrong with it that prevents that. Well, give us a paper we can look at that explains why that is so, and doens't just baldly assert it. Or if you choose to explain this yourself, give us references (books should be OK in this case) to back up your derivations. In any case, you haven't done your job as advocate if when asked for backup you just shout louder. (Old math joke: paper found in great mathematician's notes for a talk: "Argument weak; use colored chalk.")

    This is all said in respect for you, because I am not contradicting you, just asking you for what any professional seminar would.
  20. Nereid

    Nereid 3,582
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    I am going to be considerably less polite than SelfAdjoint. :surprised

    Juan R., if you are so busy, why are you wasting time writing posts in Physics Forums? Surely your precious time would be far, far better spent slaving over a hot sheet of paper, churning out revolutionary new theories of physics and piercingly accurate rebuttals of string theories? Or, perhaps, formatting your next great paper, in preparation for submission to PRL?

    Now, before any reader reaches for the mouse to click the "Report" button, let me add that I greatly value Juan R.'s contributions to this thread, and PF in general; I am only calling him (?) to account on something he must surely have to hand (if he's serious, and is doing his own research, he will have to have these references before he can submit a paper in any case). Or, if not, then isn't reasonable to conclude it's little different from 'a snow job' (have I got the American idiom correct?)?
  21. Would you mind sharing with us what you found to be wrong with it?

    I never said that. :wink:

    I never said that, either. In fact, there exist formulations in which strings propagate in curved spacetime. For instance,

    AFAIK, supersymmetry coupled with GR is the limit of superstring theory, but instead of Riemannian manifold, spacetime is a supermanifold.

    Right then. What's wrong with that? The fibration of the four dimensions? The Calabi-Yau n-fold? Again, the same thing as with T-duality - can you show that something is wrong with those approaches?

    Also, Lindé doesn't seem to be completly against string theory:
    Last edited: Jul 16, 2005
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