Friday, June 26, 2009

Trántorian physics

Trantor is a ficticial planet presented in the Isaac Asimov series of books about the foundation. It is the centrer of a galactic imperia.

In that universe the king of sciences is psicohistory. By that name is referred a mathemathical model of human societies with detailed qualitative predictive power. Physics has become an obsolete discipline that had dead of success long time ago. Supposedly it had answered all the basic questions and no new important discovery had been made for hundreds of years.

But still there were some physicists. The problem with them is that the lack of new experimental results had resulted in a vicious system where the quality of one particular physicist depended on the knowledge of the achievements and, maybe, his ability to reinterpret them in new, basically irrelevant, ways that didn't lead to new discovering.

Well, that is fictional. But sometimes actual physics somewhat resemblances that trantorian physicists. Lot of people like to culprit string theory for that, but I don't agree at all, it is a problem common to all the alternatives.

I mean, what actual observable predictions make alternative theories?

LQG great achievement was the frequency depending speed of light. In fact Liouville strings also predicted that Well, FERMI/GLAST has almost ruled that possibility (although there is some discrepancy on the interpretation of results depending of who
writes about it, for example Lubos Motl and Sabine Hossenfander disagree, as always).

Horava's gravity, being as a classical theory slightly different from Einstein's gravity makes predictions not too hard to measure. But after the initial explosion of papers it is somewhat stopped now due to some papers that posed serious doubt about is goodness as a quantum theory despite being power counting renormalizable. It would have been nice to see how it was received in the actually developing strings 2009 conference, but this year there is no live broadcast nor, at least until now, none bloging about it.

Nonconmutative theories are also almost dead, despite they had some time of glory (although today, afther many months, there is a paper in arxiv in the subject There are two types of NCT theories, field theoretic ones, and geometric ones. The fist are inspired in string theory. The last ones re mainly geometric and were promoted by the mathemathician Alain Connes. They mde a firm prediction, a value for the Higgs mass, that was ruled out (at lest in the original way, I am not sure whether some modifications have been suggested) last year by measures of the tevatron.

So, basically, we have that despite many theoretical efforts in many different approaches to basic physic (i.e., particle physics) we have no new experimentally confirmed since the formulation of the standard model, in the last sixties and former seventies of the past century. The only new result was the confirmation that neutrinos have an small mass. The other experimental news come from cosmology, and, as I said in previous posts, are not so firm as laboratory experiments.

Is this a problem of theoretical physicists. I hardly think so. String theory is a very rich framework. Different aspects of them actually are promising candidates for phenomenology. For example the mesoscopic extra dimensions suggested by Arkani-Hammed et all in the last nineties was a very original idea, that has led to cheap experiments that had put new bounds on the size of that dimensions. LQG, as said did a good prediction (shared by most Lorentz violating theories) and LQC is trying to do observable predictions about cosmology, maybe not rigorous ones, but if the were observed none would care too much about it ;).

The big problem I see is not related to theory but to experiments. And, specially, to collider experiments. USA cancelled founds for a new linear accelerator in the nineties. The LCH schedule has seen almost five years of delay (that is, if finally beguines to operate in September, as expected). The tevatron has made it's bests, going beyond the expectations. It has showed that QCD at high temperatures behaves not as a quantum gas (as expected) but as a quantum liquid.That doesn't means new basic physics, but at least it gives clouds about the properties of QCD that are very hard to study mathematically and computationaly. And, hey, it has ruled out NCG ;-). Even there are some possibilities that a careful analysis of the collected data would find the Higss bosson. Not that bad for a recicled collider.

If there is no serious money inverted in experiments researchers are going to spend time in increasingly twisted theories. Internal coherence is a good guide, but it is not clear that that alleged coherence is so free of doubts as some people try to present it. That goes for LQG and for string theory (and the alternatives). Again that is not a reason to go again string theory (or the alternatives, well, some of the alternatives are theorethically unlikely, but still). The ultimate justification of the theoretical developments is that they re made searching for compatibility with known physics and also guessing new phenomenology. What is seriously need is that experiments would be made. The LHC is, hopefully, next to operate, but there s no serious project for the post LHC.

Maybe some people could think that there is no good reason to expend a lot of money in that expensive experiments. Specially not in the current economic crisis. In my opinion that is a narrow minded vision. Certainly other areas of physics are giving interesting results (solid state/condensed mater and the wide area know as nanotechnology) but they are based on very all basic physics. It is necessary to pursue the development of new physics. For example, one very important problem that the society need to face is the energy supply. There are discrepancies about how many fossil combustibles (specially at cheap prices) remain. In fact that depends heavily on the growth of demand. But sooner or later (and most likely sooner) they will extinct. The "ecological" alternatives (solar energy, wind, etc) are mostly propagandistic solutions. Nuclear energy has better chances, but it depends on a limited resource,uranium. Certainly there are proposals for fast breed reactors that could create fissible elements. But they are somewhat experimental. It is an open question where they will operate as expected. The other alternative, nuclear fusion is fine. But again governments are not spending enough money on it (as the fate of ITTER clearly shows).

The thing is that when we are looking for energy sources the best thing we can is understand how the universe behaves at high energies. If one looks at the way on how "energy sources" work one sees a common pattern. One has a two energy state system separated by a barrier where the difference of energy between the two states is greater than the energy of the barrier. If one supply the system with energy enough to go over the barrier when the system goes to the lower energy state it returns more energy than the employed one. That is the way chemical combustibles work. And also the way nuclear fission and fusion works. Nuclear process involve higher energies and so they return more energy also (well, in fact it could be otherwise, but it would be very unnatural).

Well, if we go to higher energies one expects that, somewhere, there will be some systems that share that property (a good name for it would be metastability).For example in some supersymmetric models there is, if R-symmetry is present, a lightest supersymmetric partner, LSP, which is stable, and a candidate for dark matter. And also there is the possibility of a NLSP (next to light supersymetric partner) that would be metastable. Well, that is the kind of thing we like. One would expect that there is a big energy difference among them. If they are found and it is discovered a way to force the decay of the NLSP into the LSP we would have an energy source. Moreover, dark matter represent the, 75%, 90%? of the mass of the universe. That could men that there is a lot of it out there. One could argue that if we are not able to do nuclear fusion, using known elements we badly could develop a technology to extract energy from something that is still hypothetical. But the truth is that we don't know. Maybe it is a lot easier to extract energy form dark matter (let it be (N)LSP, WIMPS or whatever) that from known sources.

Still there are other possibilities. There is an small possibility that if the LHC creates black holes it could also create wormholes. Wormholes (lorentzian ones) have received a lot of attention in SF as a tool for interstellar travel or even as time machines. But there are other interesting uses for them if they would actually exist. If one mouth of the wormhole is posed in a very energetic environment it could drive that energy onto the other mouth by a direct way. For example one could put one mouth deep inside the earth and the other in the surface. That would be a good way to extract geotermic energy. Of course one could think that is a lot more likely to use more conventional ways to get that energy, but still it could be not. Other very energetic environment would be the sun. It is not totally clear how much energy requires to create a wormhole, but one would expect that if the outer distance between the mounts growth the same applies to the required energy. But it could again not to be so. Still there is a problem in using the sun, the gravitational interaction. The gravitational field of the sun would be transferred together with light and it could alter the earth orbit.

There is a more interesting possibility for wormholes (or maybe we would call them warmholes, or not, depending on how one would worry about double meanings of words xD). If they are created at the LHC that would probably mean that the reason behind it is that mesoscopic extra dimensions exist. In string theory there are various ways to realize that sceneries. A common feature of many of them is that the would mean that we leave in a three dimensional (or effectively three dimensional) brane. But it is possible the existence of additional branes. It could be that some of them would have a high background energy. And it also could be that they would bee not too far away into that additional dimensions. Actually they could be so near that it wouldn't be improbable that a wormhole could be created with one mouth inside that hot brane and the other in ours. Still better, the sceneries with mesoscopic extra dimensions offer good possibilities for wormholes becoming stable. That would rise the possibilit to use that wormholes to extract energy from that hot branes. Depending on the details they could be a mean to solve all the energy requirements of the human kind at a level that exceeds all the actual xpectations.

All the hipothethical energy sources that I have presented are related to string theory likely situations. Alternative theories maybe also would offer options. For example black holes in alternative theories could not evaporate completely and one could use the remanents to extract energy from them in Penrose lie process. A serious problem with it is that without mesoscopic dimensions there is no way to create black holes in the LHC so we woudn't have remanents either.

By the way, black hole physics is a very good example of trantorian physisic. Specially the black holes inners. The gravity/LQG community has a, widely accepted, viewpoint of them where the radius behaves as a time coordinate. Well, in string theory there are very different proposals, none of them too friendly with that LQG viewpoint. Also the string theory strongly supports the complementary principle. Well, some people in LQG don'even know of it's existence (or at least not until they published a paper that was incompatible with that principle). My problem with this is that we don't have a near black hole to do experimental tests. In fact even if we would create them into the LHC it is not clear that we could make experimental tests about black hole inners. Neither is too clear how that black hole inners have any consequence into the behaviour of the event horizon. Well, if naked singularities are allowed the thing would improve, but then they wouldn't be black holes ;-).

Well, certainly in this post, apart of some sociological consideratins, I have presented very speculative ideas with two few details about them. Maybe that is what top notch physicist do in trantor. Not being there I hope to present more earth based physic in next entries ;-).

By the way, if one is absolutely serious about it many proposal for alternative "ecological" energy sources are actually less unlikely to be good alternatives to oil that the ones I have proposed here. They look otherwise because they are based in things that laymen think that they understand, but if one goes into the details of the implied physics one really hope that wormholes actually exists xD.


Lumo said...

Dear Javier, of course that the situation of our world's physics is similar to that of Trantor.

The GR and the Standard Model have been known for some time and they're enough to explain, describe, and predict pretty much all phenomena that can be observed or produced for less than 5 billion dollars, if you allow me to put it in this way.

Where you're wrong is that there is something wrong about this situation. There's nothing wrong and whether a science-fiction writer says something else is irrelevant for science. It's just a sign of success. It is about dreams of past generations that have been almost completely realized, but not quite completely.

Of course that in our world, being a physicist requires first of all a good knowledge of all the accumulated insights, especially because they're likely to form "most of physics" even as it will be known in 10 or 20 years, and in the creative realm, of course that it needs one to be able to organize insights in better ways than previously. (And string theory is doing so in remarkable ways.)

How can anyone doubt it? This is just where we obviously are. We have been in this situation for quite some time. When I was a kid, the situation could have already been described in this way.

I entered physics with the full knowledge that this was what we were, and our task was to streamline some "details" at the top energies which were probably not directly testable.

It was nothing shocking for me. On the contrary, it was always obvious. What is shocking is that many people in the 2000s began to demonize this obvious situation and pretend that there's something wrong with it - something wrong with theoretical physics and its already existing achievements. That's what I find dangerous. They're stupid yet loud people who are living in a fictitious world where the right effective theory is not known. They can't live with the fact that our world is already at a higher stage of evolution of science. They're not up to the job of dealing with science at this higher level - they're dreaming about becoming famous by saying simple things - and they want to discourage, insult, or otherwise harm all people who are doing actual science that matches our actual present knowledge.

These people are crap.

Otherwise, while I expect that we essentially agree about basic things, you seem to write several bizarre technical things. A frequency-dependendent speed of light is no "achievement". It is an inconsistency, a kind of theoretical counterpart of cancer. Such an inconsistency means that a given theory can't account for the basic principles of modern physics, as summarized by 1905 Einstein's relativity. There is nothing spectacular about saying that things don't work out to be Lorentz-invariant: it is just a denial of modern physics - an attempted return before 1905.

Similarly, fashionable trends like Connes' "noncommutative geometry" particle physics or Horava's theory were never reasonably supposed to last. Every good physicist kind of knows that all such things are guaranteed to die away because they deny something else we already know - that the rough framework behind the fundamental theory is given by string theory.

This is no longer an open question, either. Anyone who starts by the denial of this insight is guaranteed to find nothing of a lasting value, so all the excitement about such "alternative" projects can be nothing more than cheap temporary fads that have to be media-driven because they don't have any inherent intellectual power.

mmfiore said...

I am convinced that neither quantum mechanics nor string theory will turnout to be the final theory of everything. I believe this because I have never encountered an interpretation of the present formulation of quantum mechanics that makes sense to me. I have studied most of them in depth and thought hard about them, and in the end I still can't make real sense of quantum theory as it stands.

There is an alternative though:
There exists a group of people that are challenging the current paradigm in physics which is Quantum Mechanics and String Theory. There is a new Theory of Everything Breakthrough. It exposes the flaws in both Quantum
Theory and String Theory. Please Help us set the physics community back on the right course and prove that Einstein was right! Visit our site The Theory of Super Relativity: Super Relativity

Javier said...

Dear Lubos, I am glad to see you here,what a surprise!.

I think that yes, we agree in many basic questions. But I have some diferent viewpoints in some aspects.

You seem very confortable with the fact that string theory is far from the rimentally obbservable. I don't totally agree. On one hand if theorethical physics wants to keep getting funds from politics iguess than that's not the type of thing they like to hear.

On the other hand, from more scientific arguments I neither think so. I think that we agree that there two types of interesting developments in theorethical physics. On one hand we have conceptual breakthroughs. In string theory the discovery of dualities , D-ranes 8that lead to M-theory and F-theory) and the AdS/CFT would correspond to that category. On the other hand we have the kind of creative ways to see observable effects hiden in the general framework. Inthat category the Arkani-hamed idea of mesoscopic extra dimensions and the posibility of observale effects derived from it is the best example,. It has not been confirmed experimentally, ut it could have been so (and now Nima would be a noble prize ;)).

My idea is that maye there are more unexpected ideas of that kind waiting somewhere that could lead to observale effects.

Javier said...

About the frequency dependent speed of light I of course know your rguments agains it. In this post I simmply stated what the lQG people said about it. If you ask my opinion I, besides your objections,find somewhat surprising that the LQG people is so proud with eeing purist abbout background independence and they are so confortable with Lorent invriant violation that attack the purism of GR at least as much as the lack of a background independent formulation. Other bad point of the LQG comunity is that in their declartion of intentions the urged to seek observational consequences. Well,they did this "prediction" in the 2003 or so.but since them, 6 years, no new "predictions" have been made. neither any grat theorethical achievement as far as I know. In that sense they are more "trantorian" that string theory (besides the internal consistency problems that you, and others, have exposed).

Said all this I must also add one observation. I would make a distintion betwen 10 dimensional Lorentz invariance and 4 dimensional one. And moreover a distintion among Lorentz invariance and the behaviour of photons. Are you sure that it is totally imposible that it is impossible some scenary instring theory where despite of 10dimensional lorentz invariance is totally ruled out that tiny effects woud affect the behaviour of photons' Specifically, is imposible that they couldn't suffer some aditional red shift beyond the one due to universe expansion? I have beguined to consider that posibility recently, and once i have considered that i think that , although less likely, a frequency dependence of sppeed could also be possible. The major objection seems to be that there is no observed red shifth for photons within our galaxy.But I guess that I can evade that argument. Well, anyway I still didn't have time to go too deep in it, I need to learn many aspects of cosmology before. My motivation to consider that posibility is that it could lead to an alternative explanation of the observations that lead to the idea of the acelerated expansion of uiverse in a way that woud be coherent with all (at leas I hope so)) the other aspects of cosmology.

Onthe previous paragraph I thnk that there is a reason to keep an eye in the alternative theories. IF LQG people woudn't have made that "prediction" I woudn't wonder about the posiility of seeking a way for conventinal string theory leading to the same effect (that can be good or bad,I guess you will say that that is bad).

Anyway, everybody knows you and iis fine thaty the readers of this blog can read here your objections with the "alternative" theories here, agian wellcome ;-). Inthis blog I always am clear about how expert, or non-expert, I am inthe themes I treat so I guess I am not confusing people. It is good that an expert like you prsent a more contundent viewpoint.

Javier said...

Er, ok, posily to ask for 4-dimesnial lack of Lorentz invairance compatible with 10 dimensional one is a dum question, forget it. But maybe still the photons could do weird things despite he present of Lorentz invariance.