Thiel-Kasparov debates

If you have 52 minutes, you may want to watch this video full of intelligent enough debates between the renowned chess player Garry Kasparov (a chronic world ex-champion and a sort of a political activist in Russia) and the renowned venture capitalist Peter Thiel (the founder of PayPal, the first major Facebook investor, a libertarian, and the supporter of world-changing projects, especially by college dropouts):



Video posted via Kasparov's YouTube channel

The topics include Google and its vision for the world, the replacement of humans by machines, the bad consequences of any looming nuclear war, politics in Russia, simultaneous chess games (in which Kasparov hasn't lost since 2001; Thiel is a very good player as well, he was surely strong enough in Nice a few years ago to beat your humble correspondent pretty much "reliably" back in Nice – but my chess scalp is surely not a source of pride for anyone who actually plays the game regularly).




They should have co-authored a book, The Blueprint, but the project has apparently been canceled. Maybe it was just delayed and renamed to The World of Fake Values where they argue that despite the widespread opinions, the world is switching to a slow development of technologies (Kasparov's words around 4:00 sound like an anti-singularity theme...). But maybe the comments about that other books are also obsolete and the book under this title was cancelled, too.




I am interested in your reactions to their ideas. This blog entry was later updated and extended.

At the beginning, Kasparov praises Thiel's intelligence and the breadth of his interests. I must confirm that. He was listening and meaningfully commenting on my remarks about particle physics and e.g. the discoveries that the LHC was or wasn't going to make back in 2010. And that was just a minor interest relatively to biology and evolution (or the lack of it) that he knows a great deal about – partly because he used to study it somewhere, or something like that. He also followed the climate debate (Richard Lindzen was the main speaker about this topic).

Around 3:30, Thiel betrays that it's really a program for Germans and he was born in Germany – he speaks German for a while. (Update: At the end, I learned that it was aired on ZDF, the Second German Public TV Channel, in 2010.)

At 5:00 or so, Kasparov says he had visited Google some weeks ago. It was about Deep Blue and computerized chess. Kasparov thinks that brute force "solved" the problem of computers playing chess well. Well, it's not a fully solved game, I would add, but the computers got better than the humans.

The discussion switches to the question whether machines or machine-human combinations are better and why. Thiel says that the Google ideology says that the computers will replace humans in 20 years. Technology advocates don't like to speak about the failures of technology, Thiel adds. To question a technology has become the greatest heresy, he thinks.

The next topic around 9:00 is whether politicians are smarter people, what they want to spend the money on, and whether Obama is a socialist. In an elevator, near 9:30, we learn that Kasparov isn't optimistic about too many things. Perhaps about the ability to convince the people to look for new ideas. Robots (and ancient ones; and some robots with GPS and cameras) showed by a guy. Another robot chap says that robot got faster and they're asked about the dates when robots will do certain things.

At 12:40, a 2010 Oslo talk by Thiel is shown, saying that technology may be used both for freedom and against it. We shouldn't be utopian about technology. Instead, it's important for us to use it, use it as the first ones, and use it now. At 13:10, Kasparov laughs as he describes the Internet just as a by-product of some work at CERN. Kasparov argues that except for speeds, iPads etc. can't do anything that PCs couldn't do 25 years ago. ;-) It sounds a bit exaggerated to me but I surely agree that the science-fiction novels written half a century ago were more optimistic about the speed of the robotic progress than the present reality. 40 years after Nixon's great words, we still don't have a cure for cancer. We're 40 years closer to the solution, however. ;-) Thiel adds that no one believes that the cure will come in 5 years. (I am actually ambivalent.)

15:50 – some fancy cars I've been in, too. ;-) 16:40 – chess was a good benchmark to measure the computers' progress because it has wisdom. Well, I surely disagree with that proposition. Chess has always been clearly just a particular game that is being won by brute force and the progress in the algorithms etc. was pretty much guaranteed to be just a gradual evolution, not a result of revolutions. There are other, deeper tasks that do require qualitative breakthroughs to be mastered by machines. BTW we're told that over a million of games a day is played via the Internet. At 18:00, they visit a chess club. A minute later, Kasparov doesn't want to play Thiel – it sounds like he doesn't want to crush Thiel but I am not sure whether he realizes that Thiel wouldn't necessarily be hopeless. ;-) Finally, Thiel plays a speedy game against the chess club manager. Thiel (white) doesn't accept draw at some moment. However, it seems he loses at the end and Kasparov is telling him what he should have played differently. Maurice Ashley, a British chess grandmaster, appears.

In the car, 25:40, Thiel says that when he's facing stronger players, he feels that the doom is coming gradually. Kasparov is skeptical and suggests that it depends on the strength of the opponent ;-) (he clearly wants to say that if Thiel played against Kasparov, Kasparov would destroy him rapidly, after a single move that turns out bad). Kasparov mentions his insane record in the simultaneous exhibitions (20-30 opponents at the same moment): no loss since 2001. Kasparov modestly tells us that he just has the stamina to walk around, keep pressure, and the 20-30 enemies just collapse. ;-)

At 28:00, they enter the Empire State Building. It sounds like I have been to the top more often than Thiel. :-) Kasparov boasts he knows the date of the construction. Thiel says that the inability to build a new World Trade Center for 9 years is a bigger failure than 9/11; this suggests that the video is from 2010, at least this part of it. Kasparov talks about some craziness in Russian politics. Kasparov said that the opposition wasn't important, the internal fights under the surface are more important, and young people massively want to flee Russia. Anywhere. Older folks are upset. A general degradation of the country follows.

They visit a human rights activist (in the Human Rights Foundation). He says things are getting worse. That's why they exist etc. Kasparov says that the West doesn't want to interfere, another problem. Thiel mentions a correlation between human rights and the economics (I mostly agree – after all, the human rights are a luxury that the wealthier ones are more likely to afford) – and a country with some ten-to-fourty inflation. The host prepared about 10 different coffees for Kasparov, all kinds – a repayment of the same debt. They discuss the immense inefficiency of the U.N. and lame excuses why it's inefficient (12 languages: but Marriott etc. can do these things profitably, anyway). Thiel says that in 20 years, the iconic status of the U.N. evaporated. The host partly disagrees – some people worship the U.N. – but he says that the U.N. isn't helpful. What should we do, the host asks? Shout loud, Kasparov suggests. Both famous guys propose technological progress as a solution to make the good guys and nations more influential. I am not sure it's this straightforward.

The host says that the human rights fight has become bureaucratized and therefore unappealing for the young; it is mostly a business for old folks in suits who talk in the U.N. The foundation wants to change it. They want to bring in Thiel and his technology and Kasparov and his brain that defeated the IBM computer – and the host believes that he did. ;-) Thiel is frustrated mostly by places that are screwed for a very long time. The host says that we're "racists of low expectations" who think that Haiti won't achieve much which is why we're not holding them accountable. Nice but your humble correspondent of course adds that it's the rational attitude because the expectations aren't just pulled from the air. They are built on lots of hard data that probably won't go away and it would be foolish to think that they may be ignored and the countries may be suddenly totally different than they are. The host says that every country may switch from liberal democracy to dictatorship in a decade. Well, yes, but certain other key things – that also determine the potential to return to liberal democracy – won't really deteriorate this quickly. Kasparov says that democracy has become just a word that may cover terrible atrocities, too. It may but it is a valuable arrangement by itself, one that increases the nations' chances to be decent, too. The host gives the Russian skateboard to Kasparov and the Chinese (?) skateboard to Thiel. Kasparov asks why Thiel received the Chinese ones, the answer is incoherent, but Thiel doesn't get offended easily. ;-)

41:30 – skateboards loaded to the cars. How will it end, Thiel asks? Growth etc. is the only optimistic scenario. For Kasparov, Martians' landing is more likely. Huh? Various degrees of recession and depression are discussed along with the world war (I was never into these doomsday scenarios much). Another bad outcome is a move to the left: governments confiscate the wealth everywhere. If the money doesn't have any value, the system doesn't work. I think these are sort of weird conspiracy theories. Money had an important value even in the communist world. You just can't suppress such basic parts of the human nature and the life of societies.

44:20 – dinner. Peter: a moment for classical liberalism to return. (Klaus is perhaps returning to top Czech politics, as a savior.) Kasparov talks about Buffett who predicts America's fall (China is next). Thiel points out that Buffett is all about avoiding the technology completely. Even on Mars, people will eat candy bars. ;-) Regardless of China, Thiel feels that you can only do decent things in the U.S. Kasparov says that Obama et al. don't care about technologies. Obama is just the community organizer, not a leader. Thiel says that they're not focusing on important things. Kasparov says that they can't even identify them. Thiel idealistically says that technology is "doing more with less" (austerity is "less with less", printing is "more with more"). Food arrives. Worries about propagation of nuclear weapons. Thiel thinks that the risk is underestimated. Kasparov points out that nations value life differently. Dictatorships are powerful because of fossil fuels etc., if the dependence on them is reduced, things get better. Well, I think that he contradicts his previous comments. A reduced dependence on fossil fuels will make the fossil-fuel-producing countries poorer and therefore even more screwed. Thiel asks what makes Kasparov continue while being pessimistic about most day-to-day issues. Kasparov is a born optimist, we hear. There will be too many questions and a few people who will give answers.

End of dinner, good bye, it was fun.

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Imagining 10 dimensions

Peter F. sent me a link to this video, Imagining 10 dimensions.



It has 104 minutes but based on various hints and a quick selection, I believe it must be a pretty good one for an apparent amateur creator! Correct me if I am wrong but I hope you won't! ;-)




I hope that at least one more reader will find the required spare time to watch it.




Note that Imagining 10 dimensions is also a blog.

For others who are more busy, a homework problem: Where have you seen the background color under the Calabi-Yau manifold from the video at 1:39:06? ;-) It's actually an originally Mathematica animation that was redone with other options.

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A video on loop quantum gravity

Sabine Hossenfelder watched a 43-minute video on loop quantum gravity that was posted two days ago. She wasn't too impressed.

Well, I am always impressed by low-budget or no-budget teams that manage to shoot a semiprofessional video of this size but it's hard to avoid some criticisms. Most of them are really criticisms of the topic they chose to cover, loop quantum gravity, so they shouldn't be used against the creators of the video. And I will avoid detailed criticisms of the imperfect sound quality (noise filters were used too much at some places), the subtitles (and whether it makes sense to have a video if there exists a written form of it), and the speakers' limited rhetorical abilities.



00:00 It's strange that loop quantum gravity is being connected with the birth of stars etc. because it isn't really capable of explaining the particle spectrum and other parts of physics that are crucial for our understanding of the early Universe.




00:40 Loop quantum gravity is said to be "treating gravity quantum mechanically". While this phrase is omnipresent and seems like an innocent one, and it can even be interpreted innocently, in the strict form – which is probably one chosen by most of the speakers – it is a seed of lots of confusion. A theory of quantum gravity isn't just the same classical physics "treated" differently. It is new physics, a brand new theory that leads to different conclusions and predictions. The procedures needed to find a quantum theory with certain properties are, in general, more complicated and different than just "placing hats on the heads of all objects in classical physics". Loop quantum gravitists sort of understand that a quantum theory differs from a classical theory. But they live in the misconception that the transition from a classical theory to a quantum theory is straightforward and one-to-one. It's surely not. The space of quantum theories with certain properties is completely different from its classical counterpart. Their consistency conditions are different, and so on.




00:50 LQG is said to tell us that space has discrete units. Well, it pretty much assumes it so it's misleading to say that it's a prediction. And this assumption has indeed far-reaching consequences – far-reaching destructive consequences, to be precise. It makes the theory incompatible with the Lorentz invariance, other continuous symmetries, and it is a property that guarantees that the infinite indeterminacy seen in the non-renormalizable Einstein's theory can't be cured by this attempted theory. It's unfortunate to hype this property of LQG without asking whether it's actually a good thing or a bad thing and without making a credible attempt to answer this question. But this hyping is being done not only by filmmakers but also by most LQG proponents.

01:00 Ivan Agullo is said to be a "rising star" of the field. I've never heard of the name and INSPIRE seems to confirm it's not my fault. I don't quite get the concept of a "rising star" whose most famous paper has 52 citations shared by 5 authors. It's surely an inflation of words. What about an average young researcher in this subpar discipline?

01:10 Abhay Ashtekar is a pleasant guy. In some of his features of the smile, he resembles Cumrun Vafa (Vafa is Iranian while Ashtekar is Indian by his roots). He read a book by George Gamow as a kid. So did I. Agullo loved algebra and calculus. I don't quite understand why we're told these stories about the childhood of someone whose contribution to physics still remains completely unknown to me – and all other viewers.

02:20 Are you afraid that Einstein failed and you're trying to solve it? Agullo says Yes but it's OK because many people are working on it. Well, many people with much lower capabilities couldn't replace the genius of one individual. What allows modern physicists to go beyond Einstein is their much better mastery or quantum mechanics and related portions of physics. Unfortunately, this can't be said about the LQG researchers which is another reason why they should be afraid of their inevitable failure.

02:50 Ashtekar: Einstein's GR is geometric and predictive, QM is different, probabilistic and algebraic. There should be a unifying theory. These sound like innocent words for every "unifier" of gravity and QM. However, the vague formulation about the two limits – which are completely different and which impose very different restrictions on the unified theory – is a seed of confusion within LQG. In particular, the postulates of QM have to be exact and they affect every dynamical degree of freedom and interaction in physics. On the contrary, the foundations of GR are about one particular field only, the metric tensor or the field communicating gravity, and its interactions with other fields while most of the other degrees of freedom remain unconstrained. Moreover, the original equations of GR don't have a reason to be exact and aren't exact. LQG folks don't understand these differences.

04:05 Ashtekar: Gravity is encoded in the very geometry of spacetime. Well, the same is true for every theory that respects the equivalence principle, e.g. string theory. However, in string theory, one may derive such conclusions from a more fundamental starting point. Ashtekar says things like "there is no background and everything is interacting with everything else". These two statements aren't equivalent. The background is just a condensate that must be allowed to develop and exist. So if you can't get background from your theory, it's doomed. You can't mask this doom by demagogic identifications of the lethal flaw "there is no background" (bad) with the principle that "everything is interacting with everything else" (true, it does in pretty much every theory).

05:44 Comparison with string theory. LQG folks from the GR background, ST came from particle physics. So we're told by Ashtekar that string theorists are focused on the unification of forces and not the peculiar properties of the spacetime itself. That's just untrue. String theory has discovered and still studies lots of new remarkable properties of the quantum spacetime – T-duality, mirror symmetry, other dualities, holography, entanglement is a glue or wormhole, emergence of spacetime from other degrees of freedom, topology change – flops, conifolds, others. It's just a lie that string theory isn't fascinated and fascinating us with new insights about the peculiar properties of the spacetime in the quantum theory.

06:20 In string theory, SUSY and extra dimensions are essential, in LQG, they're not. Friendly speculations about the cooperation of LQG and ST. Not really realistic but OK.

07:30 Agullo about the Big Bang singularity. GR fails over there. He uses "loop quantum gravity" and "loop quantum cosmology" in the same sentence. It's pretty bad that they don't even explain enough to explain the viewer that these are two things and what the relationship between them is. Sabine has already complained about it. LQC isn't really a limit or special case of LQG; it is a simplified toy model of it. It suffers from all the problems of LQG and more. The "cure" of the singularity is presented as an extra quantum-caused repulsive force that creates a bounce. I find this 1) a wishful thinking, 2) a naive strategy to deal with the problem. Such a bounce only moves all the problems to (even more serious problems with) the pre-big-bang cosmology and it doesn't seem one has made any progress at all.

08:50 Sponge has a maximum capacity to hold water, and space has similarly a maximum density. That's just stupid. Even semiclassical GR is enough to see that the density is maximized for the minimum-size i.e. Planckian black hole when it's Planckian, too. But this is really just a transitory regime, not an extreme one. Lighter black holes are like elementary particles and their density isn't too well-defined or isn't finite because they're pointlike in some very specific sense. Larger black holes have a much lower than the Planckian density, and so do all other celestial bodies. There's really no way to make a whole "filled sponge", a macroscopic piece of the maximum-density "material" of space, and if a theory predicts otherwise, it's immediately dead. It's dead because the final stage of the collapse of localized matter is a large black hole whose density (mass/volume) is much lower.

09:50 Big bounce instead of Big Bang. Agullo says the naive things about the bounce, without really solving anything. One could really embed this "solution" even to classical GR as long as one adds some (non-local) interaction. But we really do know there was a Big Bang and by the second law, the entropy "before it" if there was any "before" couldn't have been higher than during the Big Bang. Agullo explains terms in a high-school-level equation but it's both incomprehensible and inadequate for analyses of extreme physical conditions such as the Big Bang.

12:00 Ashtekar says that this bounce force comes out automatically blah blah blah. He's happy about it. It's hard to see where this satisfaction comes from. Every new theory predicts some new effects. A generic effect is bound to get corrections from the new physics. This is not yet a reason to be happy. It is not a consistency check analogous to those in string theory. There are no successful consistency checks in LQG.

13:00 The female narrator starts to talk about cosmic inflation. What does LQG say? Ashtekar says confusing things about the probability of inflation that is small at some moments and so on. Bizarre. Inflation is a generic process that arises in theories with scalar fields and viable enough potentials that are surely not "infinitely unlikely". It arises whenever a region of space sees a scalar field sitting near the maximum of the slow-roll potential. It even arises without the slow-roll potential. Once the small region obeys this condition, which must be clearly allowed because it's an allowed configuration, exponentially large volumes of inflating space will be created. All the "inflation is unlikely" criticism trying to argue otherwise is complete unscientific gibberish, and so is Ashtekar's story about this topic.

14:40 Ashtekar also praises LQC for giving us a preferred instant, the bounce, while the Planck time after the Big Bang isn't special. Those comments are extremely special, too. The Planck scale surely is special in a theory of quantum gravity. Special things tend to occur there or its vicinity by dimensional analysis. On the other hand, the bounce in LQC isn't special, at least not the exact moment, because the evolution isn't time-reversal-symmetric (e.g. because the second law of thermodynamics) so the volume-minimizing instant is just a convention to choose a moment in the middle, and not the only convention. So the situations are equally special or non-special.

16:00 She asks a surprisingly sensible question – doesn't the observed positive cosmological constant rule out the recollapse, namely the bounce? Agullo says that LQC doesn't predict that there will be a recollapse. That's nice but it does say t – or at least they do say - that there was a bounce so it was a collapse of an earlier Universe. One has problems with this in a positive C.C. world, too, especially because the pre-big-bang universe had to be more or less maximally symmetric due to its low entropy.

17:40 Why was the entropy low at the beginning – which is not the beginning in the bounce models? A good question. Agullo says that the entropy was "reset". Wow. I suppose he means that an agent reduced a high positive value to zero. Jesus Christ? This is a flagrant violation of the second law and it is enough to kill any model with this feature. He talks this rubbish to a laywoman for many minutes and she has no way to learn that it is rubbish contradicting basic physics, even physics taught to undergraduates.

19:30 Ashtekar correctly says that we usually count matter entropy and not horizon entropy. But he doesn't elaborate upon this good point. One has to be a bit careful about double-counting here. Well, the matter entropy is always parameterically lower than the horizon entropy so if we count the horizon entropy, it beats the matter entropy, anyway. Ashtekar is trying to solve the same problem as Agullo by equally if not more childish comments. The entropy is "infinite" at the bounce and it drops to zero because the horizon disappears. But this is just an oxymoron. The event horizon is always defined relatively to the causal structure of the whole future spacetime. So if it's somewhere, it just can't disappear. Ashtekar's comments about the disappearance make no sense and they're added on top of Agullo's nonsense about the "reset entropy". Moreover, the idea that one may just ignore the decreasing matter entropy is also wrong. One may only ignore the disappearing matter entropy in GR if the matter ends in a singularity. But if it doesn't, the matter density separately can't decrease, either. Those folks are a community of sloppy folks who just support each other when they talk vague physical nonsense.

21:50 Resolution of black hole singularities. There are no precise calculations, we hear. They hype a Pullin-Gambini paper that happens to be about a similar question. The singularity is replaced by a new large spacetime. You know, that's a big problem, something that would revive all the information loss puzzles after they were solved.

22:50 She asks about Alan Guth who dared to publish a paper that bounces are prohibited. Agullo says that Guth assumed classical GR near the bounce while LQG violates it. Ashtekar agrees. She also asks about other problems of contracting universes. Agullo just says that there are "papers" and they imply that singularities don't appear. But this really means that the theory disagrees with GR in rather mundane contexts, a point that isn't noticed at all.

25:00 Ashtekar is worshiping the repulsive force. I can't get rid of the feeling that these people still live somewhere in the 17th century and they're adding terms to Newton's equations. Physics no longer operates like that and similar extra terms aren't considered fundamental or interesting. Ashtekar says that unlike previous attempts, LQC has a way to make a "cube of size 10 Planck lengths" uniform. I suppose that the mechanism he refers to is the Jesus Christ who resets the entropy and flattens the region. That's nice but the Jesuits already had the same mechanism (Jesus Christ) many centuries ago. All this stuff is ludicrous. Inflation and things equivalent to it is the only known actually operational mechanism to produce flattened, nearly empty large regions of space out of a different environment.

25:45 Ashtekar is asked about the proposal by Smolin – whom he doesn't like – and a physicist with a Polish name that black hole singularities are big bangs of other universes. Asthtekar thinks that this can't be the case because the singularities are different.

26:50 Ashtekar is asked whether inflation may be eternal according to LQC. He doesn't seem to have an answer. He has no intuition, we hear, and asks others to do a strange calculation.

28:35 Agullo is asked why the previous Universe contracted. He says we don't have observational access to this question. That's a fun excuse because if you claim to have a theory replacing the Big Bang singularity, it should give you a mechanism for that process, too. After all, we don't have the observational access to the Big Bang singularity which doesn't mean that we can sweep it under the rug. He's using different standards for his pet theories and the (more viable) conventional theories. Agullo says that quantum effects wash out the information about the previous phase. Great. But the theory should have the information about the overall evolution, otherwise it says nothing about the early Universe.

29:10 The female narrator complains that a paper by Guth et al. (Borde, Vilenkin, Guth) didn't refer to LQG. Well, Alan Guth rarely cites crackpots in general. Agullo meaningfully explains the paper, saying that it claims that inflation can't be eternal in the past. At the end, he says that the theorem may be ignored but there is no justification except for foggy claims that we don't have the final theory yet. A great power of the theorem is that they may prove many things even before we know everything else, a point that Agullo clearly fails to grasp. Ashtekar says that the theorem doesn't apply to LQC because LQC has a contracting phase, something assumed to be absent in the theorem.

32:25 It's hard to test quantum gravity experimentally; interesting that no one dares to criticize these folks for this fact of Nature. Random wrong papers about the Lorentz violation by gamma-ray bursts, wrong ways in which black holes should evaporate, and so on are hyped. The CMB is most promising for Agullo except that his LQG has nothing to say about it.

34:00 Ashtekar says that everything we observe is compatible with LQC. Wow. An unexpected conclusion after half-an-hour of hyping the difference between LQC and the theories that actually do agree with the data.

35:40 Violations of Lorentz invariance due to the discreteness space were experimentally falsified "while other experiments have confirmed it" (the latter is bullshit, all these positive signals have been debunked or explained as being due to a more mundane effect). Ashtekar says that this violation of relativity is a robust prediction of LQG, in analogy with crystals in condensed matter physics. Very true: LQG imagines that the world literally is a sort of a crystal. So why doesn't he see that LQG has been ruled out? He wants to believe that the correction only contribute at the second order. But even the (experimentally falsified) first-order correction is a wild underestimate of the huge violations of relativity that a fundamentally Lorentz-violating theory predicts!

37:10 Detection of gravitational waves, polarization of CMB, etc. What does LQG have to say about these matters? The only honest answer, nothing, isn't heard.

38:50 Small black holes at the LHC. They would be great, Agullo says. All this stuff is incompatible with the LHC because black holes may only appear at the LHC with the extra Randall-Sundrum warped dimensions which aren't a part of LQG. Agullo doesn't explain this fundamental thing – either he doesn't understand it or he finds it beneficial to hide the fact.

39:50 The narrator talks about a Planck press conference, anomalies, differences from WMAP. The video doesn't look honest concerning the question who authored these comments. They're not hers, are they? Agullo talks about some perturbations from the pre-big-bang cosmology and while the gap between the conventional physics and LQC is deep, he blurs the boundaries so that it is often completely unclear whether he is talking about the LQC research or proper physics. Ashtekar admits he doesn't understand these anomalies so he offers general wishful thinking about learning things about the initial state instead. We're told that Planck data are compatible with LQC except that LQC predicts nothing that looks like the real world, and talking about details of Planck data in this context is way over the edge.

The narrator wraps the video by comments about an entirely new vista that the bounce may open.

I don't plan to proofread this text.

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Stephen Hawking got a flat tire

...but sang the Big Bang Theory theme song...

Just like your humble correspondent yesterday, Stephen Hawking got a flat tire which is why he couldn't be at the Comic Con. At least, he prerecorded this monologue:



He also sings the theme song of TBBT, a very successful sitcom of CBS that is nominated for Emmy 2013 much like Sheldon Cooper and Amy Farrah Fowler.




Much like Sheldon Cooper, I am the last drafted man when teams are being divided in collective games – unless there is someone on the wheelchair. But it seems likely that Stephen Hawking would be drafted ahead of me, too. ;-)




If you listen to the monologue carefully, you will also notice that Hawking announced a new book and a new movie, both of them primarily about himself. You may already buy the movie today for $3,900.

Via Daily Mail (where you may learn the theater by which the TBBT actors sold the message from Hawking)

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Cumrun Vafa: Strings and the magic of extra dimensions

One month ago, Cumrun Vafa's son determined that he needed to go to Bangalore, South Central India, and because Cumrun is a good father, he went with him.



So why wouldn't he give a public talk (one hour and one second) about strings and the magic of extra dimensions at the local campus of the Tata Institute of Fundamental Research?




In the first sentence, Vafa denies that he was there by pure coincidence. He always wanted to visit India etc. ;-)

The sound quality isn't great... Moreover, you constantly hear the transmission from cell phones. Bangalore is a major global center of outsourcing and telephone services for various corporations so the audience may be just working while listening to Cumrun. :-)

He starts with Newton, a galaxy, and the flat space. Then (6:55) he shows the same smoking Einstein animation that I am using in my public talks as well. :-)




Around 7:00, the space already gets curved and waving. Straight lines in spaces of positive and negative curvature look like attraction or repulsion. LOL, at 12:24, there's another exact picture from my public talks, the structure of the atom. I suspect that Cumrun may have used the file of mine. ;-) Yes, I use this exact picture of Feynman at 12:50 and the animated Feynman diagram at 13:05, too. :-)

Disasters from the QFT+GR union; strings arrive around 15:00. He recalls the bizarre birth of string theory – a cute formula; there seem to be strings in it. 16:50, quark goes to string, another animated GIF from my public talks. The same about the animated string Feynman diagram at 17:35. Just to be sure, I gave Cumrun the permission to use anything used in my presentations, especially because I didn't create most of these pictures. Yup, 17:55, another one. Here he's also saying very similar things that I am saying at similar places of my talks and this agreement comes from two independently thinking brains.

At 30:30, Cumrun declares the string dualities to be the deepest discovery made by physicists in a century. Quite a big statement but surely a justifiable one. He says many excited things about the magic that a dual description emerges in each regime and we don't know how. It was a surprise and we don't quite know why it happens. Well, I sort of feel that I know why it has to happen. The issue is that in any asymptotic limit, there has to be a simplification and a hierarchy between energies from various objects/contributions and if a new low-energy continuum forms, it may always be organized into states of an object with a certain number of dimensions.

Lots of brane physics etc. Around 46:20, a stringy calculation of the CKM matrix is boasted. Smooth topology changing processes. We should be proud about the extra dimensions, not ashamed of them.

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Lisa Randall on Higgs, physics, real world

If you have 49 minutes, you may listen to this interview of the Lip TV's Walter Kim with Lisa Randall.



She just celebrated the 15th birthday this week, with whatever permutation of the digits you find appropriate, and her twin sister Sabina Křováková just won the Czech and Slovak Superstar (local American Idol).




At the beginning, she explains the importance of approximations and layers of science. Clearly, these are similar ideas that Ken Wilson is celebrated for. This is important to understand the relationship of science to claims about religion, too. The host identifies controllable approximations with sloppiness, something she has to clarify.




High-energy physics is looking for the most fundamental laws – which isn't all of science – and she quickly starts to explain where extra dimensions fall into this scheme. The host dismissively says (here) that aren't extra dimensions just a way to escape from problems because what we tried doesn't work. Of course that they are but the dismissive tone is completely unwarranted. Science always does progress in this way and it's exciting! I get somewhat more angry when such idiotic anti-science laymen's "questions" are being asked but Lisa Randall got slightly upset, too. ;-)

It's still important whether a broader paradigm is capable of solving some problems and whether it is actually the right solution. This is what science is all about. This is why science is exciting.

Then they continue with the tests of the new theories at the "supercollider", i.e. the LHC. Lisa explains that she isn't working "just" on extra dimensions, of course. Randall reveals that she would prefer a higher-energy collider such as the SSC. Natural and man-made accidents at the LHC are distinguished; Lisa thinks that sometimes laymen manage to understand why the LHC isn't dangerous for the world.

Lisa communicates with the host in an interactive way, not hesitating to correct various misconceptions and distortions that are either said explicitly or in between the lines. For example, the host starts to talk about the "feeling of consistency". So Lisa rightfully insists that it's not about feelings; it's about objective tests that establish or not establish the consistency.

People are unexcited about new technologies until someone creates it and everyone has to have it. ;-) But Lisa also emphasizes that we are curious even when we subtract technological applications. Science works. For her. But Lisa is also asked about some philosophy and history of whether or not people trust science or religion. It depends where people apparently get their power from. People thinking that the power is inaccessible etc. tend to mistrust science, Randall concludes.

We hear about a fun Earth science class that predicted that a particular place would be flooded etc. She hasn't learned much from the humanity classes. The host talks about the hero status of scientists etc. when he was younger; Lisa tends to emphasize the satisfaction of a person who is getting the answers. She points out that not only brute physical limitations but also the financial limitations are slowing us down. How much do we want to invest?

Why computers can't do research? Why can't they write novels? Some comments about the combination of rigorous, almost mechanical work and fuzzy creativity are offered.

She would like some topics to be approached more scientifically. Climate change is quoted as an example. Well, at this level, I surely agree. We can't quite be 100% certain. I am just 99.999% certain that there's no serious conceivable problem with the climate in the next century or two but that's enough of a certainty to scientifically dismiss the doomsayers.

How is the U.S. rewarding scientists etc.? Some time is spent with the evaporating leadership of America in science. Lisa doesn't care about the nationality of science too much but she finds the trends scary, anyway. Some supportive comments about the pure basic research are heard. Lisa remembers a discussion with researchers in a less prestigious science, biology, who were told by her that physics is all the stuff that actually works at the doctor's office. But we don't even do it because of that! ;-) Investments in science itself has never hurt us, Lisa thinks.

Is still science penetrating the mass culture? Does she enjoy science-fiction etc. She thinks that it makes people think more broadly about things. Quotes from Casablanca, the film, were about physics and they could afford it because the viewers were familiar with it. Lisa tries to jump to the U.S. contributions to the LHC – a non-member that has more physicists there than anyone else – but he returns to popular culture quickly. ;-)

Is science thinking in the root of culture? There are many other aspects, like eating, in which nations are unified. ;-) Is your field getting so detached from the public? Lisa writes books because people care. Some people care, others don't. There are different levels of understanding, too. Just like in books about classical music etc.

Some platitudes and claims that science is or isn't immoral wrap up this exchange.

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Supersymmetric Google Hangout with John Ellis

According to a 2004 SPIRES survey, the CERN particle phenomenologist John Ellis of the U.K. was the second most cited physicist in high-energy physics and, except for the third one (Steven Weinberg), the only one surpassing 50% of the citations collected by Edward Witten. ;-)



After 2004, he actually added over 170 papers with 6,000+ new citations, which, along with the new citations earned by the older papers, brought him from 33,000+ to 53,000+ now. At least in the discipline of citation collection, you should definitely not forget about John Ellis! You may also know John Ellis as a maverick who dared to disagree with the great high school teacher Walter Wagner who had calculated that the LHC would devour the Earth. Also, his CERN introduction to the Higgs field earned over half a million of views.

Most of his research has gone well beyond the Lagrangian terms on his T-shirt on the image elsewhere in this text; in other words, he's been primarily researching Beyond the Standard Model physics. Today, you may ask a question – or at least a question about supersymmetry – to him.




On Thursday, 5 pm Prague Summer Time i.e. 11 am Boston Daylight Saving Time i.e. 8 am Californian Daylight Saving Time, there will be a Google Hangout (Google+ page) with him about SUSY on youtube.com/CERNTV. Use @CERN #askcern on Twitter to ask questions. If you click at the last link so far, you will see that I have already tried to ask a super top classified question. I don't expect the true answer to be revealed but the chance is nonzero, perhaps 50-50. ;-)




Incidentally, the first tetraquark (a pair of mesons stuck together) called \(Z_c(3900)\) was discovered by Japan's Belle Experiment as well as Beijing EPC a few days ago, see e.g. Nature.

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Richard Feynman: Fun To Imagine

You must have seen many excerpts from the following video featuring Richard Feynman:



But maybe you have never watched the whole 66-minute-long video. Here it's waiting for you.

He covers lots of things – need for imagination in physics; heat is wiggling; surface tension is the attempts of molecules to get in...




In a similar way, he explains using the atomic language why gases cool down when they expand. And thousands of other fun things...




Various atoms like each other to various degrees. Wood and oxygen. They get caught and create lots of jiggling which is spread elsewhere and what you get a catastrophe. The catastrophe is called fire. ;-)

Where the did carbon get there from? It came from the air. The wood is from the air: it grew by absorbing carbon dioxide. Just a little bit from the ground. These anthromorphic stories about the life of the atoms sound funny.

He also traces the energy – it ultimate comes from the Sun. Where did the Sun find the jiggling (energy)? He has to stop somewhere...

How do rubber bands work? There are chains of molecules but other molecules are jiggling and hitting the chains, trying to shorten them. It only works when the rubber is warm – heat is necessary. Rubber bands' temperature goes up when you stretch them and vice versa. The jiggling is inside everything.

Around 14:40, the scene about "what the magnets feel" starts. You must have already seen this exchange. An irritated Feynman repeats the claim of the author of the question that it's an excellent question but makes it very clear that the question was utterly idiotic, too. When we ask "why", we must have some facts that we're allowed to use as more fundamental facts, parts of the answer. Magnetism is more fundamental than the macroscopic events we know from the everyday life.

At 22:07, we switch to a dentist and a water dam. Turning wheels in the dam make all the wheels in the city turn. It's all about iron and copper, a natural thing. Again, he points out that there are long-range forces that are more fundamental than the "direct touch" forces we know. Gravity is much weaker; but it may matter when the electric forces etc. get neutralized.

31:40, fraternity at MIT gives questions like: Why you get left-right but not upside-down reflected in the mirror? ;-) A fellow Junior Fellow in the Society of Fellows (humanities) was impressed by this question and didn't want to believe that I could solve such a problem. ;-) The actual mirror only reflects the front-rear direction. We just psychologically imagine that the image is rotated around the horizontal axis – this rotation is a symmetry unbroken by the gravitational field – which makes the image left-right reflected.

34:50, what keeps the train on the tracks? The planes of contact are tilted, regulating the direction back if the train is destabilized much like the differential – something that the trains don't need.

37:20, seeing things. A not too pretty woman sitting in the swimming pool allows one to watch the waves instead. Sensitive spots in the eye. Mess of waves in the space (electromagnetic fields with all the frequency modes) and complicated mechanisms in the eyes and radios. As a kid, I was also stunned when I realized the idea that all the information about all the radio and TV stations is flying around me in the room at the same moment.

At 43:20, he talks about scales. Big numbers. You scale yourself to imagine them. Why Earth is round. Nuclear fuel. Neutron star matter – balancing gravity and pressure. Pulsars – they're the same thing. Immense densities, confirmation of predictions. Black holes.

54:30, ordinary people like Feynman can master these things. There are no miracle people. With some investment of time, he becomes a scientist. A bit too idealistic. 55:20, his research is a nutty mixture of equations, ideas, and vague pictures of equations. In every man's head, the imagery is probably very different from others. Translation engines work hard. He thinks so because different people solve problems differently. Feynman couldn't do counting multitasking; someone else uses an optical system for counting.

1:00:55, I have already linked to this many times. We're used to understand very different phenomena than the fundamental ones. Quantum mechanics is wonderfully different than the macroscopic world. People who try to reduce QM to some mundane or classical mechanism will be defeated.

Incidentally, when I talk about quantum mechanics, let me modestly mention that the first tag in the history has earned a gold badge on the Physics Stack Exchange. Which tag was that? Yup, it was quantum mechanics. Congratulations to Bohr, Heisenberg, Dirac, Schrödinger, Pauli, and a few others, too! ;-)

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Dirac's 1975 lectures

Spiros found this remarkable 1-hour talk by Paul Dirac in New Zealand in 1975:



Recall that Dirac was born in 1902 and died 1984; so he was 73 in the video above. He is a serious man but there's a lot of room for his memories as well as some jokes.




There are actually four talks. The first one above is on quantum mechanics; the second one is on quantum electrodynamics; the third is on the magnetic monopoles; and the fourth one is on his largely incorrect large number hypothesis (variation of universal constants).




Even if you focus on the first lecture on quantum mechanics, there's a lot of interesting stuff to listen to. He was impressed by the successes of the old Bohr model of the atom. He identified the key property of Heisenberg's quantum mechanics to be the non-commutation of the observables. He thinks that Heisenberg himself was afraid of this feature – much like almost every originator of a great idea is afraid of the key revolutionary relationship because it could also very well spell the doom for his pet idea. But Dirac himself wasn't afraid. He took it seriously.

At the end, he also mentions that he doesn't believe renormalization unless the quantities are renormalized by small amounts. He explains the success of the renormalized quantum field theories by comparing them with the successful old Bohr model of the atom which was fundamentally wrong, too. Well, Dirac was both right and wrong in his counter-revolutionary attitude. He was wrong because the success of renormalization is no accident, of course. He was right because it's possible to reorganize the field theory in such a way – a way using counterterms – that the renormalization is small, indeed. However, you must still accept that there are counterterms that cancel the loop divergences. I am not sure whether Dirac understood the Renormalization Group and similar insights of the 1970. He may have already been too old for that.

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Boston Marathon blasts

The video below shows one of the blasts a few meters from the camera (that starts to swing); the other blast is heard elsewhere 13 seconds later. Think twice whether you want to watch it at all.



It's a special negative feeling to see people murdered at a place that I know so well as the place above. There's the Old South Church on the left side of the video above (Google Maps); the Copley Square with the Trinity Church (and the Hancock Tower next to it) would be seen just 100 meters further on the right side.

I've been in downtown Boston approximately (at least) every other weekend during my 6 years at Harvard. Boston proper was just a more attractive place for me than Cambridge – the latter is kind of provincial, boring, and full of hypocritical leftists while Boston is a proper, ideologically diverse megacity with the life and business of all kinds one expects from an unfiltered center of America.

Moreover, one doesn't have to walk for 2 miles to find a fast-food restaurant with hamburgers in Boston – a type of business that the leftists apparently want to eradicate.




You may hear that the sound of the blast was loud and guaranteed to create panic. This was a truly vibrant place and, it's easy to say now, a rather natural target for terror. Relatively speaking, the number of casualties is rather low. Thank God but let's not thank Him too much because it's still bad.




I have no idea who is behind the terror – nothing to say except that I would surely also catch and investigate a 20-year-old Saudi student if I found one next to the explosion. It's a good idea to monitor potentially dangerous – while simple enough – activities at similarly vibrant places. On the other hand, I hope that America will be wise enough not to overreact. Life shouldn't be stopped because of one explosively sad event.



The map of the blasts; thanks to Joseph S.

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Michio Kaku's confusing Higgs remarks

I partly but not quite agree with Sean Carroll's and Matt Strassler's criticisms of this CBS interview (HTML) with Michio Kaku, a co-father of string field theory and a sometimes excessively lively popularizer of physics, not to mention more general aspects of science fiction marketed as science:



Sorry if CBS inserts half a minute of ads.

It seems that Michio Kaku who watches The Big Bang Theory on the same TV station – together with 20 million Americans in average – couldn't resist to incorporate the Big Bang to his new story about the Higgs boson. And the result of his creative artistic work sounded strange to physics ears.

However, see also Phil Gibbs' take on this which is closer to mine.




The fuse behind the interview was the CERN announcement a few days ago that the 126 GeV Higgs-like particle really behaves like the Standard Model Higgs boson. The agreement is striking but I think that this "event" has been heavily overhyped.

We've been learning that the new particle is extremely similar to the Standard Model Higgs boson for more than a year and we have had very strong prior reasons to think it's the case, anyway. Moreover, the evidence that the particle behaves in the Standard-Model-prescribed ways was growing gradually and there wasn't any real eruption a few days ago.




Michio Kaku says that the event was huge and champagne was flowing in physics departments throughout the world. I am not sure. What I am sure about is that this was the legitimate description of the excitement on July 4th, 2012. Champagne was surely flowing across the halls of the Institute for Advanced Studies in Princeton, New Jersey. If you care about the microscopic details, Nima Arkani-Hamed paid for the beverage and Robbert Dijkgraaf, the director, was the waiter. Yes, it seems like Ed Witten, Juan Maldacena, and others had to be satisfied with the role of rank-and-file drunkards.

So aside from the confusing timing, Kaku's colorful description of the excitement sort of conveys a true story. And yes, Michio Kaku may be expected to make similar stories sound a little bit more spicy.

Also, CBS used the term "God particle" and Michio Kaku actually mentioned that the phrase usually makes physicists cringe. Well, as you know, I have no real problem with this phrase and I even think that it's arguably more polite and fair when it comes to the credit that should be given to several fathers of the "Higgs" mechanism.

Bizarre claims about cosmological links

But the most controversial point of the interview is the claim that the Higgs discovery helps us to understand how the Universe began. Michio Kaku even says that the Higgs boson is what gave the bang to the Big Bang and that it is the missing piece of the Big Bang theory, and so on. These highly unusual comments are combined with the usual remarks that the Higgs field gives masses to all other particle species.

Well, a physicist will have a trouble to understand why exactly the Higgs boson should be responsible for the ignition of the Big Bang. The Higgs condensate was born and it was immediately important a trillionth of a second after the Big Bang when the electroweak phase transition took place. But all other fields were very important when the Universe was dense and hot, too. There have probably been many other phase transitions right after the Big Bang, too. So why is the Higgs field getting these exclusive rights to boast the authorship of the Big Bang?

As several later sentences by Kaku reveal, Kaku justifies his idiosyncratic hype by the Higgs boson's being a relative of the inflaton. And yes, the inflaton is what probably gave the bang to the Big Bang. In fact, five years ago, I discussed some problematic yet intriguing models in which the Higgs boson actually is the inflaton (a paper with 250+ cits). For these models to work, there has to be an uncommon interaction term in the Lagrangian, the squared Higgs multiplied by the Ricci scalar:\[

\LL_{\rm tot} = \LL_{\rm SM} -\frac{M^2}{2} R - \xi H^\dagger H R

\] The usual minimal theory has \(\xi=0\) but for \(\xi\) of order tens of thousands, you start to get a behavior in which the Higgs field may behave as the inflaton, too. Well, these models are problematic (the Lagrangian above mixes a nicely renormalizable Standard Model with the non-renormalizable gravity treated as a field theory and various extra problems result from that) and they have surely not been demonstrated at the LHC. On the other hand, I don't think that the LHC has brought us the relevant data that would exclude these couplings to the spacetime curvature, either. Am I wrong? I realize that the LHC has surely excluded many other, more conventional yet non-standard non-gravitational couplings of the Higgs field.

But even if we ignore these unpopular models, I must sympathize with Michio Kaku's general point that the Higgs boson is the first fundamental scalar we have discovered in Nature and it belongs to the same family as the (still hypothetical) inflaton. And the scalar fields are those that may get vevs so they're naturally more important than the spinning particles for various phase transitions and other changes that have been shaping the character of the Cosmos around us.

In particular, fundamental scalar fields are mundane in string theory and because assorted non-string theorists have proposed various memes and would-be reasons why fundamental scalar fields shouldn't exist in Nature at all (think about the philosophy beyond preon theories of numerous kinds), the discovery of the Higgs boson is a positive point for string theory even though, of course, string theory is not needed to explain the existence and the behavior of the Higgs boson. However, in a non-stringy setup, one is offered various reasons why such fields could be forbidden in general while string theory has always unequivocally stated that scalar fields should exist.

So I don't think that there exists a justification to say that the Higgs boson (or field) found at the LHC is the key particle (or field) that launched the Big Bang.

On the other hand, I do think that the Higgs field (and its quanta) did play a somewhat elevated role right after the Big Bang, especially during the electroweak phase transition. The cosmological spin of the Higgs boson discovery is certainly an unusual rhetorical exercise but I would personally not trash Michio Kaku just for saying something that is unusual – because within the error margins that are unavoidable in similar shows and proclamations addressed to the laymen, his story isn't qualitatively less true than the other things that are often being said about the Higgs boson (and other things) in the popular media.

In fact, I can even turn Kaku's claim that "the Higgs boson is the last missing piece of the Big Bang theory" to a valid claim by making just one modest modification. Replace the "Big Bang theory" by "the standard model of cosmology" which is pretty much a refined synonym. The standard model of cosmology contains the usual solutions to Einstein's equations of general relativity but, in a less central way, it also incorporates the Standard Model of particle physics. The latter is needed to understand many events right after the Big Bang. Because the Higgs boson was the last missing particle of the Standard Model of particle physics, you may perhaps also say that it was the last missing piece of the standard model of cosmology – and therefore the Big Bang theory, too.

Well, I needed a long explanation to partially justify Kaku's words but the same is true for many other popular "licenses" that are constantly repeated by the popularizers of science. The only difference is that everyone knows the "partial justification" of the usual stories but because Kaku was the first major pundit who have spun the Higgs boson discovery in this cosmological way, almost no one understands the justification for his oversimplified story. I tried to give you one. Be sure that Kaku's cosmological interpretation of the Higgs is much more justifiable by physics than Carroll's cosmological interpretation of the origin of the arrow of time!

So I would give Michio Kaku C– for accuracy but A– for originality. ;-)

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Nima at STScl: don't modify gravity, understand it

...because it is a moral issue...

It's not the first time when Nima Arkani-Hamed gave a "totally negative" talk on a similar issue but it's a fun time.

Twelve days ago he came to The Space Telescope Science Institute (STScI) in Baltimore, Maryland – the terrestrial headquarters for Hubble (past) and James Webb Telescope (future) and a loose part of Johns Hopkins University – and had the following things to say.



Video:

Don't Modify Gravity—Understand It! (video, 85 minutes)

He is introduced by a host who enumerates some prizes Nima has received, including a nice one from Milner, and mentions that the only person over there who would understand the talk is Mario Livio who is just recovering from an illness (fortunately for his health, unfortunately for the readiness of the audience).

Nima claims to have a special moral right to give an entirely negative talk about the sinfulness of modifications of gravity because he's been a dirty sinner himself. ;-) So that's why he has the credentials to crawl from his hole, confess, and repent. Of course, he means it's wrong to modify gravity at long distances. Of course, GR isn't adequate at super short distances, an issue he later (around 15:00) talks about, too. Gravity just becomes an intrinsically strong force over there (at the Planck scale).

Nima debunks the usual vague philosophical attitudes about general relativity's being justified by the beauty, sexiness of geometry, and similar stuff. Instead, GR works because it's inevitable; it's dictated by consistency on top of special relativity and quantum mechanics. This provable inevitability shows how deep our knowledge of physics has become. He sketches his plans to discuss the cosmological constant problem and learn from the epic failure of every single attempt to solve the problem by modifying gravity at long distances. He divides the theories to the deeply flawed ones that he would spend his time with, anyway; and complete idiocies that are not worth talking about at all, despite a thousand of deluded papers about them.



The experience has numerously shown that physicists have to be radically conservative instead of conservatively radical. Well, in this case, he claims that the conservatism leads to the landscape. OK, his more technical comments start with the proof that gauge theories and gravity are inevitable.

Nima attacks the claims in the popular books that "we don't know how to combine gravity and quantum mechanics". Obviously, neutron interferometry may be done and measured (and used to show that Erik's Verlinde entropic gravity is crap). Obviously, we may talk about gravity and quantum mechanics in the same sentence – otherwise we couldn't have discovered quantum mechanics on planet Earth (where we have gravity) at all. In fact, we may even calculated the leading-corrected Newton's law:\[ F = \frac{G m_1 m_2}{r^2} \zav{ 1 - \frac{27}{2\pi^2}\frac{G\hbar}{r^2c^2} +\dots} \] We can questions like that! The effect is minuscule but we may still calculate it. Quantum mechanics is a robust framework that can deal with anything. The real difficulty – sad properly – is that we don't know what happens with various terms in gravity at short distances which is why GR needs a replacement. I couldn't agree with him more. Note that Nima attacks not only really crappy popular books such as Lee Smolin's ones but even the really mainstream ones such as Brian Greene's books. Needless to say, I think that Brian's confusing presentation of the conflict is biased towards his completely flawed tendency to modify quantum mechanics whenever he sees a vague opportunity or excuse for that. ;-)

Fine. Nima returns to long distances. Photons would produce a wrong negative-norm polarization. Gauge invariance ("redundancy", using his more favorite words) is needed. The same goes for the diffeomorphism redundancy and gravity and spin-2 fields. These gauge redundancies aren't real symmetries – they're artifacts of our imagination. He continues with Weinberg's arguments from the 1960s that the interactions with added photons – regardless of the nature of the theory – have to depend on the polarization vectors for these interactions to remain nonzero at long distances. Now, pure gauge polarizations have to decouple (interaction amplitude going to zero) which implies that the total charge is zero and therefore, there has to be the "symmetry".

The same with spin-2. You don't have to know anything about the "culture" of gravity or the word. The spin-2 needs to decouple the bad polarizations. This forces the conservation laws for the momentum in this case. As I have explained many times, the allowed spins of massless/light particles are \(0,1/2,1,3/2,2\) and the last three choices inevitably arrive with increasingly constrained gauge redundancies.

Nima says many things I repeat many times. Someone comes to you and tells you that he may have a completely new spiritual viewpoint on gravity, based on some torsion, wakalixes, or any other word. We just don't need to care about these vague words and fog! We may study what the theory predicts for the interactions and whatever it is, it will either agree with the "gauge descriptions above" or violate the general postulates of relativity or quantum mechanics. That's it, we're finished, "anything goes" is just wrong.

At 35:40, he begins to talk about the cosmological constant problem, the most frequent excuse for modifications of gravity at long distances. Everything is Planckian in the fundamental theory, so should be the density or curvature of empty space, but it is empirically 123 orders of magnitude smaller. There are contributions to the C.C. that are Planckian, after all, and they must cancel with the huge relative accuracy (classical terms against quantum corrections etc.). The cancellation isn't an inconsistency, however ludicrous it may seem. People used to believe in the fantasy that there was a deep so far unknown reasons why the C.C. ultimately exactly cancels. Its nonzero value made this scenario far less plausible: it almost cancels but there must still be a tiny leftover. Oops.

Nima compares this situation to the fantasies in the 1930s when the first divergent loop corrections to QED were seen. It was believed that those infinities were fantasies that would ultimately see a redefinition of QED that makes all of them zero. Well, they were finite but they were definitely not zero. Loop corrections at every order matter and are nonzero, although much smaller than the naive (infinite) value. As a stumbling block, the case of the C.C. is more serious; as a stimulation of the progress, the story of the loop corrections to the magnetic moment was far more dramatic.

When written as an energy density, the C.C. is the fourth power of the inverse millimeter. So some new physics could be appearing at the millimeter scale. Except that we have looked and there seems to be nothing over there. (We think that the analogous solution does explain the hierarchy problem, the unbearable lightness of the Higgs' being, however.)

Now, at the level of linguistics, a great idea to explain why the C.C. is so small is to "degravitate" the vacuum energy, all the modes of the fields or those whose wavelengths are shorter than the millimeter (this refinement is needed to preserve the tested behavior of gravity at distances longer than 1 mm). Everything else gravitates but this form of energy just happens to exert no gravitational influence, the proposal says. However, physics only starts once you begin to convert the word-level ideas to equations and 99.9% of the word-level ideas simply fail at that point.

A slightly clever mechanism to realize similar ideas was "dumping curvature in the bulk" of a higher-dimensional space. Of course it's easy to "solve" the C.C. problem if you're allowed to modify the behavior of gravity, e.g. by changing the exponent in Newton's power law. The discussion turns to examples in lower-dimensional gravity (3D gravity with deficit angles), too.

A modification of the idea is based on Randall-Sundrum who managed to "trap" gravity on the brane. At the beginning, it looked like the tower of apparently massless Kaluza-Klein modes of the gravitons may provide you with a loophole. However, one may ultimately see that the RS theories end up being effectively equivalent to normal four-dimensional theories, GR with massless matter. I know that Lisa doesn't like these "RS is equivalent to..." comments but I am afraid (or happy to see) that Nima is right. It's not just the full-fledged AdS/CFT methods that argue in this direction.

More exotic ideas (53:00) came from DGP, Dvali-Gabadadze-Porrati (it's a messed up GDP; I really disliked those things from the beginning and without an interruption because they seemed so contrary to all the lessons I learned from string theory). The Einstein-Hilbert term is weighted by a coefficient that only makes gravity matter on our brane; it's extra 4D gravity added on top of the normal 5D gravity. Your humble correspondent thinks it's inconsistent at the quantum level (swampland). Surely in string theory, it looks like gravity only affects "all of space" and the "\(D\)-dimensional space with all the dimensions one can find". At any rate, Nima shows that if the crossover state obeys the inequality needed to dump the curvature etc., gravity on the brane will be modified at millimeter-like distances, too.

Deficit angle didn't work because it can't go over \(2\pi\) or so. With an excess angle, this limitation seems to be lifted. Things look fine. However, if you're diligent, you derive the propagator in your theory and alas, it is modified, too. Some \(2\pi\) becomes \(2\pi+|T|\), in some units; the tension is added. For a large tension, the tension term dominates. You recalculate at what distances gravity starts to behave properly and you find out that these distances must be larger than the Hubble scale (the size of the Universe). Too bad. ;-)

A model after model after model fails like that. Why all of them fail? It's useful to hit your head with a hammer 10 or 20 times, then you may start to get the message. ;-) The reason behind the failure of all these things is relativity. Relativity relates space and time. If you modify physics at some distances, you modify it at some time scale, too – or break relativity or causality.

More technically, your stress energy tensor \(T^{\mu\nu}={\rm diag}(\rho,p,p,p)\). The different components have different sources – the C.C., visible matter, radiation – and there's simply no relativistically invariant way to "isolate" the piece that you would like to make non-gravitating without spoiling the proper behavior of matter and radiation at the same moment! The only way to avoid the conclusion would be to modify gravity by "knowing in advance" what the impact would be, and that would violate causality.

At 1:00:00, he switches to the question whether one may modify gravity at all – a purely theoretical question. Can one make gravity a bit massive etc.? Every modification of gravity has to add a new degree of freedom, typically a scalar field that couples to \(T_\mu^\mu\). That's morally nothing else than boring extension of GR with scalars such as Brans-Dicke etc., something that's been around since the 1940s. If you add the scalars, you modify gravity in a boring way – e.g. you modify the bending of light so that you are in conflict with the observations at the same time unless you boringly choose the coefficients of the extra terms to be much smaller than one (obnoxious imitators/deformations of GR that can't solve its fundamental problems such as the C.C. problem).

Exciting possibilities are those where the scalar fields are more exotic, e.g. massive gravity or Galileons or ghosts or fields with specific non-linear self-interactions. Lots of phenomenology but as I always said, these theories lead to deep conflicts with locality and/or thermodynamics. At any rate, Nima promotes the Galileons. Scalar fields are equipped not just by symmetry \(\phi\to\phi+c\) but also \(\phi\to\phi+v_\mu x^\mu\), a "Galilean symmetry" but acting on fields rather than \(\vec x\). Lunar phenomenology, fun, but to make the story short, some radial modes propagate superluminally. Despite formal Lorentz invariance, the "nice structure" is inseparable from the lethal acausality.

Similarly, "higgsed gravity" allow you to produce "black hole hair" which is enough to create a perpetual motion machine of second kind by making a cycle between two distinct event horizons of a black hole valid for two different particle species/fields. Too bad. Nima spent 8 years of his life with similar things, he says. Gravity is much more constraining than other types of dynamics. He declares that the eternal inflation plus the multiverse are the only possible way to the C.C. problem given the failures discussed above. I disagree with that. I don't have to modify gravity at all but the selection that makes the C.C. tiny may still reject the existence of any multiverse.

Of course, I agree with Nima that one has to be radically conservative instead of a left-wing as*hole because the declaration that the previous knowledge was "just wrong and may be scratched" has never been successful. Even quantum mechanics overthrew classical physics in a very respectful way – when it explained some surprising features of classical physics that should have been asked even by classical physicists, e.g. "Why can the equations of motion be derived from a Hamiltonian as well as the principle of least action?" No trashing here.

Radical conservatism – the right attitude – means that one is prepared to push the tested principles as far as they can go and only when one becomes absolutely sure that there is a problem, he may think about modifications. Nima repeated his slogan, Don't modify gravity, just understand it. And the host proposed not to modify Nima's talk by stupid questions, instead, let's drink some beer which is what they are conservatively good at.

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Leonard Susskind: black hole wars

If you have 51 minutes, you may want to watch this July 2012 (and possibly much older) talk.



Leonard Susskind is offering a verbal version of the amusing story about black hole wars in which he and Gerard 't Hooft were defending the conservative side against the progressive chap named Stephen Hawking or Evil Karn Evil for short, while chatting in a house owned by a guy obsessed by self-promotion.




Of course, the conservatives were right but even though you know the ultimate spoiler, you may find some cool stuff in the talk.

He starts with the personality description of the heroes, continues with Laplace's non-relativistic picture of a black hole (escape velocity above the speed of light). You will be shown a photograph of the physicists taken without any camera – just with the hand of Susskind who didn't even have to work hard to emulate a kid from the kindergarten.

Be ready for a pond with fish who aren't allowed to exceed the speed of sound. A sonic fishy black hole marketed by Bill Unruh. Jacob Bekenstein's defense of the second law of thermodynamics is the next topic. Hawking's evaporation follows. Only afterwords, you may want to slow down because things that people don't hear too often about are described.

He's throwing George W. Bush (and Condi?) to the black hole which indicates that the talk is a bit older. There were no Canadians because nobody knows of any stupid Canadian politicians, Susskind argued. At 27:00, we hear about the black hole complementarity. He spends some time with whether the complementarity means "and" or "or". It's "or", of course, as your humble correspondence has also stressed many times, and this "or" makes the complementarity an example of Bohr's complementarity, indeed. Too bad that Lenny got brainwashed by Joe Polchinski in Summer 2012.

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Lost City Raiders, a B movie

My newly favorite Czech TV channel, Prima Cool (which airs not only The Big Bang Theory), was broadcasting a silly 2008 U.S.-German-Austrian science-fiction catastrophic global warming film, Lost City Raiders, tonight.

If you have 98 minutes, the whole movie is right here on this blog.



I kind of enjoy watching catastrophic movies – and view it as 1% of my job, too. In this case, I feel satisfied and you should also feel satisfied because this cheap $6 million movie scored the worst grades you may think of, see e.g. 39% at IMDb.

The rest of the blog entry is full of spoilers.




It's year 2048, a power of two, and the sea level has increased by something like 15 meters (the reality will be less than 0.1 meters) which, the authors believe, puts about 1/2 of North America (mostly the Eastern 50%) under water (in reality, even 15 meters would only submerge a tiny percentage of the land).

So they realize that the IPCC was right – in fact, the catastrophic global warming was worse than previously thought, even when they said that it was worse than previously thought – and a clever cardinal from the New Vatican (which is the ordinary Vatican with some buildings replaced by floating islands above the former city) figures out how to save the Earth. They must find the staff of Moses in the flooded streets of the New York City that became a part of the ocean. A man, a scuba diver who later dies – but has two (adopted) sons – accepts the challenge and the sons ultimately complete the task (despite explosives and puzzles in the churches) and meet with their tough babes in a restaurant in order to emit a few "wise" words about the future.

You may think that the effects are cheap and unspectacular but it's probably nothing compared to the predictable and stupid plot. The movie was addressed to the most undemanding audiences and once again, we must feel some kind of a satisfaction when we see that a politically correct theme and attitudes aren't enough for success. Thank God – even though in some cases, it does look like these conditions are sufficient for success.

When I said all these critical words, I must say that I have enjoyed the movie as entertainment. My rating is 60%.

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P.S.: Some details. Moses' scepter is originally supposed to be in a Vatican library. It's not there: a member of the Order of the Temple stole it 800 years ago. So it could be in his grave in Dresden, DDR. They go there but find out that they have a competition: the former girlfriend of one of the sons, Giovanna. She's a scuba diver and self-taught geologist who tries to lower the global sea level by whole millimeters by detonating small holes in the ponds. ;-)

She's hired by an even more hopeless crackpot, the greatest owner of the land in the world, who wants to slow down the sea level rise, too. He has two methods: to hire Giovanna as a researcher who creates holes in the Mediterranean Sea so that the ocean pours into these holes (it sounds similar to some policies proposed by the IPCC); and to hire her to find the scepter, too. Well, a competition for the father and two sons. The rich guy who hired Giovanna has a spy in the Vatican, another cardinal. In Dresden, the graves have double floors etc. The father dies there after an explosion when a rock falls upon him.

After his death, the sons bring some historical object from the grave to the "good cardinal": the father asked them to do so. However, they want to abandon the risky job of looking for the scepter. That changes when the good cardinal tells them that the good cardinal, their adoptive dad, as well as their (late) biological fathers (archaeologists) were members of a special cult looking for the scepter.

Meanwhile, it also turns out that the rich guy, Niklas, has sold his land. He actually wants to raise the sea levels and then turn it back when he cheaply buys the land beneath the sea level, and so on. He wants to destroy almost everything and control the world. His cardinal-spy is caught at some time and his motivation was even worse: he wanted to complete the end of the world, a job that God began 2 millenniums earlier. ;-)

The sons who have decided to continue in their three fathers' mission hire a busty waitress-mechanic, Carol, who gets a new coil for their boat, avoids a fat innkeeper who wants sex with her because an old placard for his pub only covers 1/2 of the value of the old stolen coil (she abruptly becomes a sweetheart of the other brother who didn't have sex with Giovanna), and they go to see the grave of Richard the Lionheart – it may be at 3 places. Giovanna and the rich guy are there before them and find the scepter. Giovanna becomes sure that the rich guy is a villain a minute before he closes her body to the grave together with Richard the Lionheart so that some archaeologists may find the bones of Richard and Giovanna in the year 3048.

When the grave with Giovanna and Richard is thrown to the ocean, it just happens that her former boyfriend is swimming around. He opens the box, saves the babe, and they easily overtake the boat of the richest guy in the world. ;-) Once they're in charge of the scepter, they notice that it works as a perfect projector. It shows a movie about Pangaea and some "electromagnetic intersections" around the Earth. By a complete coincidence, Giovanna who watches is is the only person in the world who understands these electromagnetic intersections. So their skepticism goes away. (Giovanna starts to tell everyone that science is constantly failing because they used to be 9 planets and now there are just 8 planets – surely a hot topic in the year 2048; her anti-science interpretation of the redefinition of a "planet" remains unchallenged).

They sail to one of the intersections and find out a cave. The scepter is also a key to a lock which opens a sophisticated lab. Inside the lab, there is a convenient 13,000-kilometer-deep (about 3 meters in diameter) hole through the Earth, too. :-) The plans on the walls prove that the mechanism is nothing else than what Giovanna has been working on (but a greater realization of it) – a plan to lower the sea level. The door closes, confines them, and for some time, they're afraid they would die while they could save the land. But 3 of the 4 young people escape when the door temporarily opens.

The last guy has to return to the lab in the cave when he finds out that the evil cardinal – who escaped from the New Vatican after he was outed by the good cardinal as a spy (he instantly jumped to the New Vatican waters) – tries to stop the process of the saving of the Earth. They fight for a while. Finally, the son manages to throw the cardinal to the 13,000-kilometer-deep hole and save the scepter. He restores the process and thinks that he will die. But fortunately, he saves his life, too.

The process is activated after a while. A huge hole is created in the Earth and a big fraction of the world ocean pours there – some kind of giant waterfalls. Well, as the two couples are drinking champagne in the restaurant, they're told by the good cardinal on the screen of a 2008-style cell phone that the sea level dropped by 10 meters in the Mediterranean Sea. They don't want to be annoyed by such details when they are having fun. The cardinal tells them that the sea level in other parts of the world ocean isn't dropping but it seems that they will have some extra job, to go to a few dozens of other similar spots where they have to produce a similar huge hole into the Earth to stop the flood.

All the previous activities done for the cardinal and the scepter cult were unfunded. So I suppose that the rest of the activity needed to save the Earth didn't receive a eurocent of the EU taxpayers' or New Vatican money, either. Obviously, they saved the world in a cheaper way than the UNFCCC and the Kyoto protocol.

As I have said, I developed the pleasure of watching and enjoying movies even if every second of them is completely illogical nonsense, so I liked the film despite – and perhaps partly because – of its immense stupidity and lack of realism. Realistic if not mundane yet fictitious movies and novels is something I can't stand; it's the socialist realism that I am immensely bored by (independently of the politics).

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Movie: 2012

One day later, on Sunday, I watched another catastrophic movie called 2012 and shot in 2009. Its budget was $200 million, about 30 times more expensive than the Lost City Raiders, but it was more chaotic and even more silly from a scientific viewpoint.



Full movie

The Mayan prophecy about December 21st, 2012 gets realized in a bizarre way. The Earth's core gets quickly hot and the surface is cracking, and so on. The reason behind all these phenomena? The neutrinos from the Sun "mutated" and became equivalent to microwaves. Holy crap. Didn't they also wanted to say that neutrinos started to have sex with bunnies? ;-)

Alternatively, couldn't they have just asked a physics grad student to invent something slightly less dumb if they already pay $200 million for the movie so that all the movie staff wouldn't be identified as a gang of uneducated naive imbeciles on physics blogs?

With this being said, it was clear that the effects were much more professional and expensive than in the Lost City Raiders – and I was crying like a small baby.

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