Sunday, December 21, 2014 ... Français/Deutsch/Español/Česky/Japanese/Related posts from blogosphere

Discrete spacetimes contradict Unruh effect

Two young Indian men, Golam Mortuza Hossain and Gopal Sardar, wrote a paper about loop quantum gravity and similar "discrete" models of quantum gravity whose mathematical argumentation seems vastly better than that of an average paper about similar subjects:

Absence of Unruh effect in polymer quantization (gr-qc)
Yes, the Unruh effect isn't reproduced by those theories, they say. Backreation sensibly asserted that if the paper is right, it's a way to prove that these theories are dead. Well, it's about the 500th proof that they are wrong, I would say.

These two guys' mathematical and theoretical physical advantage over an average author of "loop quantum gravity" papers seems self-evident. Show me loop quantum gravity papers that actually manipulate with the Mathieu equation, elliptic cosine and sine functions, Riemann zeta function, and even with a simpler mathematical operation in modern physics – the Bogoliubov transformation.

Saturday, December 20, 2014 ... Français/Deutsch/Español/Česky/Japanese/Related posts from blogosphere

PC revolution, Altair 8800: 40th anniversary

Fourty years and one day ago, the PC revolution started when Micro Instrumentation and Telemetry Systems (MITS) released its Altair 8800 personal computer.

In 1994, this guy, Bill Gates, said a few words about his and Paul Allen's decision to write BASIC for that machine (which was released in early 1975). Note that BASIC was invented as a popular language at a New Hampshire school in 1964.

I was just one year and two weeks old when the model was introduced. But even for those of you who are older, it must feel like some mysterious pre-history of the PCs because almost no one bought it. It was using the Intel 8080 microprocessor that is, up to relatively minor variations, still around in Windows PCs. That microprocessor was introduced in 1974, two years after Intel's first microprocessor, Intel 8008 (see its restricted instruction set).

Friday, December 19, 2014 ... Français/Deutsch/Español/Česky/Japanese/Related posts from blogosphere

Alternative teaching of mathematics: three problems

Mathematics is not just the mechanical elimination of a finite number of answers

Two days ago, I spent hours, literally, by discussions at about the Hejný alternative method to teach mathematics to the kids.

Off-topic: A group of 100+ engineers is actually building Hyperloop, Elon Musk's mach-one train that gets from San Francisco to L.A. in 30 minutes.

If I try to summarize some key points really concisely (some exchanges helped me to crystallize some of the points): mathematics is not just about the lessons that a human derives from the experience, but about the accumulated knowledge that dozens of generations of mathematicians have extracted from the experience and, even more correctly, from their pure thought. So mathematics can't be left to the rediscovery of each kid.

Now, there are differences between the kids and they will show up. Whether the kids at the top in a given subject – mathematics, in this case – master the subject well is more important than what the others do because those at the top are actually likely to use it. One may reduce the differences by forcing the kids who were not so good to spend much more time. But I actually think it is counterproductive. Kids – and adults – should better focus on things that make them happy and that they are good at. So I think that in a healthy situation, the less talented kids in mathematics will spend less, and not more, time with mathematics than their talented counterparts. Consequently, the gap will be even larger than it would be if everyone spent the same time with everything.

Thursday, December 18, 2014 ... Français/Deutsch/Español/Česky/Japanese/Related posts from blogosphere

Ellis', Silk's falsifiability babbling in Nature

Scientific American joined the community of low-brow, ideologically driven, anti-science tabloids some decade ago. Nature was keeping its traditional quality (well, almost) for much longer but recently, it is turning into another venue for mediocre pseudointellectuals to attack science – and especially quality science.

Two days ago, Nature published a rant by an average physicist and a physicist who really sucks titled

Scientific method: Defend the integrity of physics (by George Ellis, Joe Silk)
Similar offensive, intimidating rants love to use the word "defend". It reminded me of "Science defends itself against The Skeptical Environmentalist" in Scientific American (2002).

It's a usual tirade about "falsification" by people who couldn't make it to the top of science by doing real technical work so they decided to spit on the top scientists and collect points among the stupid, science-hating part of the populace by misleading populist texts without any valid technical content.

Let me be somewhat more specific about the reasons why I consider this text (and its authors) to be crap or worse.

Bitcoin: up to noise, the eternal downward trend is very likely

On November 28th, 2013, I wrote a blog post about the Bitcoin with some explanation what the money supply of the Bitcoins is and how the value may evolve. I said many things about the substance that I still believe to be true but I also included a prophesy – which was also included in the title – that the Bitcoin bubble would probably await some new peaks before it bursts.

With the hindsight, I tend to think that my prophesy was completely wrong. I am not a good prophet – because there are probably no good prophets allowed by the laws of physics. November 2013 when I wrote the blog post was actually the month when the price of the Bitcoin peaked. On November 17th, 2013, the price surpassed $1,200 at MtGox but it was before I wrote the blog post where I already talked about the "current price near $1,000", so you couldn't earn any more money by the extra investments.

Wednesday, December 17, 2014 ... Français/Deutsch/Español/Česky/Japanese/Related posts from blogosphere

Bang or bounce: a new idea on cyclic cosmology

Guest blog by Paul Frampton

Dear Luboš, thank you for the kind invitation to contribute as a guest on your remarkable blog. My subject is cyclic cosmology and will be based on a recent paper archived at 1411.7887 [gr-qc] although I will provide only a non-technical description without many equations and will begin with the interesting history of cyclic model building.

One surprising and interesting output is that no inflation is required to explain the observed flatness and homogeneity of the universe.

A philosopher's quantum mechanical delusions

It's been weeks since I was infuriated by nonsense about the foundations of quantum mechanics. A nice time, at least from this point of view. It's over now because a "philosopher" named Chip Sebens wrote a blog post at his co-author Sean Carroll's blog about his and their quantum mechanical fantasies and misconceptions:

Guest Post: Chip Sebens on the Many-Interacting-Worlds Approach to Quantum Mechanics
This babbling is "inspired" by quantum mechanics and especially all the wrong things that are being written about quantum mechanics in the popular books. So some of the sentences are similar to the truth even though they are always slightly wrong – it's never right.

I will try to focus on the things that are wrong and you should be aware of the fact that they were cherry-picked to a certain extent and you could cherry-pick some assertions which would make Sebens' essay look less bad. But such fundamental mistakes shouldn't be there at all, so his text is bad, anyway.

Tuesday, December 16, 2014 ... Français/Deutsch/Español/Česky/Japanese/Related posts from blogosphere

Shrinking ruble: Russian calmness impresses me

Thanks to the excess oil (not only) from fracking, the price dropped below $59 for the first time in a long time.

And because of this drop combined with the Russian dependence on the income from fossil fuels and because of sanctions against Russia that have almost cut the world's largest territory from loans, plus the hysteria surrounding these moves, the Russian currency dropped from 32 rubles per dollar in October 2013 to the high of 93.5 rubles per dollar earlier today. The ruble has recovered some ground since that time (to 80 now) but it may have been temporary.

The drop from some moment in Fall 2013 is by the factor of three. A crook named Michael Mann should look at the graph above if he wants to see what a real-world hockey stick graph should look like. And the graph doesn't even show the high at 93.5 today. Every day, the ruble seems to lose over 10% of the value. The half-life (in the sense of radioactivity) is about three days.

Meanwhile, in these extreme conditions, the Russian Central Bank is doing what is right – except for some interventions that always proved to be highly temporary. The last action was the increase of the interest rates from 10.5% to 17% less than one day ago.

Everyone else seems to be calm in Russia. There doesn't even seem to be any anger. I have tried to look at Russian newspapers but I wouldn't even see a single text that would blame the U.S. for this havoc. The Central Bank boss tells everyone to embrace the new financial reality while a region in Central Russia banned the word "crisis" in the public. I am just impressed by all of that.

Kids: most new methods to teach mathematics are dangerous pseudoscience

Czechia's most influential (?) news server has been bombarding the readers with hype about new revolutionary ways to teach mathematics to schoolkids.

I placed this blog post at the top again after I discussed with the advocates at
This stuff is combined with constant calls to eliminate mathematics from the mandatory subjects in the high school final exams. Folks from a despicable Faculty of Humanities at the Charles University – a tumorous department that shouldn't exist at all – are constantly involved. You can imagine that I am terrified by all that and you haven't even heard any details.

Today, an 80-year-old chap called Milan Hejný is promoting his and his father's "new method" to teach mathematics (how "new" is a method whose founder was born in 1904?) in an interview titled The kid has mathematics inside itself, just listen to him or her, the father of a revolutionary method says. Quite an uncritical title, right? However, the content of the interview is trash.

Landscape of some M-theory \(G_2\) compactifications: 50 million shapes

The first hep-th paper today is

The Landscape of M-theory Compactifications on Seven-Manifolds with \(G_2\) Holonomy
by David Morrison and James Halverson. The most important classes or descriptions of superstring/M-theory compactifications (or solutions) that produce realistic physics are
  1. heterotic \(E_8\times E_8\) strings on Calabi-Yau three-folds, string theorists' oldest promising horse
  2. heterotic Hořava-Witten M-theory limit with the same gauge group, on Calabi-Yaus times a line interval
  3. type IIB flux vacua – almost equivalently, F-theory on Calabi-Yau four-folds – with the notorious \(10^{500}\) landscape
  4. type IIA string theory with D6-branes plus orientifolds or similar braneworlds
  5. M-theory on \(G_2\) holonomy manifolds
There are various relationships and dualities between these groups that connect all of them to a rather tight network. All these compactifications yield \(\NNN=1\) supersymmetry in \(d=4\) at some point which is then expected to be spontaneously broken.

Halverson and Morrison focus on the last group, the \(G_2\) compactifications, although they don't consider "quite" realistic compactifications. To have non-Abelian gauge groups like the Standard Model's \(SU(3)\times SU(2)\times U(1)\), one needs singular seven-dimensional \(G_2\) holonomy manifolds: the singularities are needed for the non-Abelian enhanced group.

They are satisfied with smooth manifolds whose gauge group in \(d=4\) is non-Abelian, namely \(U(1)^3\).

Monday, December 15, 2014 ... Français/Deutsch/Español/Česky/Japanese/Related posts from blogosphere

Afghanistan war costs exceed $1 trillion

...15-year spending matches 30 years of GDP...

After 9/11, the U.S. had a self-evident moral capital to organize a revenge. The terrorist attacks that took place half an hour before my PhD defense were brutal, shocking, saddening, and spectacular.

This picture of Kabul makes the place look richer than it is.

The immediate damages to the infrastructure exceeded $10 billion but just by a little. On the other hand, the war in Afghanistan that was justified by the attacks has already surpassed $1 trillion (ten to the twelfth power), see CNBC, which beats the immediate damages caused by 9/11 by two orders of magnitude.

(The Soviet Union has spent lots of money for a futile conflict in Afghanistan as well – but it was surely less than a trillion dollars.)

Despite this asymmetry, the operations in Afghanistan seem far less spectacular – that's why I have included the provoking adjective above. One could argue that the money has been almost completely wasted.

Wolfgang Pauli: an anniversary

Wolfgang Pauli was born in Vienna, here in Austria-Hungary, in 1900, and he died on December 15th, 1958, in Zurich.

His 1945 Nobel prize was given for the exclusion principle but he has contributed many other things and he had the potential to discover all of quantum mechanics by himself, his friends Bohr and Heisenberg would agree.

LHC to restart in March 2015: \(13\TeV\)

Now it's the last month of 2014. So far the last proton-proton collisions – at \(8\TeV\) – occurred in late 2012. The gadget went to Two Years' Vacation and as you have known since your school days, vacations are over very quickly. It takes about two years for Two Years' Vacation to be over.

Iveta Bartošová, Two Years' Vacations (1988). Lyrics: "You [the beam] used to say: I will be back right away. It's just two years' vacation, nothing more." Well, OK, it was originally two years of military service but I found the pop song relevant, anyway.

The collider is designed for the center-of-mass energy of \(14\TeV\). I guess that it's still the plan to get to that level – maybe sometime during 2015. However, March 2015 will begin the acceleration to a somewhat lower energy, \(13\TeV\) which means \(6.5\TeV\) per proton. Collisions used by physicists should be available from May 2015. See some Google News.

Saturday, December 13, 2014 ... Français/Deutsch/Español/Česky/Japanese/Related posts from blogosphere

Entropy, temperature are not fixed linear operators

Similarly fields in GR. A simple demonstration of "state dependence" in quantum gravity

Kyriakos Papadodimas and Suvrat Raju have demonstrated that it's possible to embed operators describing the fields in the black hole interior into the Hilbert space of a black hole so that all the usual principles approximately hold.

Their construction doesn't imply that certain questions about the perceptions of the infalling observer have unambiguous answers – indeed, one may worry about the non-uniqueness implied by their construction. But I am convinced that the existence of the embedding proves (and it's not the only proof) that various AMPS-like arguments that the black hole interior can't exist in a consistent theory of quantum gravity – e.g. in string theory and its AdS/CFT – are just wrong.

The state dependence of the field operators \(\Phi(x,y,z,t)\) describing some fields in the black hole interior has gradually emerged as the epicenter of the controversy that prevents some physicists from confirming that Papadodimas and Raju have settled the broad AMPS-like questions.

Many previous blog posts – e.g. in August 2013 and August 2014 – unmasked my personal certainty that the concept of state dependence of the field operators is right. We must choose a realistic subspace of the Hilbert space – states that differ from a reference state \(\ket\psi\) at most by the action of some simple enough polynomials of the local operators – and within this "patch" of the Hilbert space, the field operators work exactly like quantum mechanics demands. However, the field operators don't have a broader range of validity – they can't be well-defined on the whole Hilbert space. After all, even the topology of the spacetime is variable which means that there can be no "universal" coordinates parameterizing the spacetime.

Here I want to promote a more obvious argument why the state dependence is inevitable. We know state dependence from statistical physics and the state dependence of the field operators is just a translation of these facts into the quantum gravitational language via the standard Bekenstein-Hawking-like dictionary.

A typical recent climate alarmist PhD

Gerrit Holl: a mindless parrot on a mission to spread the "consensus"

A week ago or so, I wanted to look how many of my 1,900+ answers at Physics Stack Exchange have a negative overall number of "upvotes minus downvotes". There is a hundred of zero-score ones (some of them have been accepted, however) but only two answers boast a negative score.

In one case, a guy was confused about the spontaneous symmetry breaking, the difference between two configurations' being the same and their being related by a symmetry. If the degree of confusion exceeds a critical threshold, it's hard to help these people because they don't have a clue what they are even asking about. They want to reshape the incoming information in their way which is incoherent and protect themselves against any coherent understanding. Minus one for me.

The second negative-score answer, also at minus one (2 pluses, 3 minuses), was about the rainfall according to global warming. It's not a coincidence. This part of physical sciences has been totally politicized. OK, so the question was:

Why we should observe an increment on the mean intensity in rainfalls and an increment on mean dry days with global warming?
The first, one-sentence answer, sends the author of the question to a propagandistic website with zero quantitative information and some vague claims about models that may predict that something is positive or negative – but the thing you should believe is that there is definitely a problem.

Friday, December 12, 2014 ... Français/Deutsch/Español/Česky/Japanese/Related posts from blogosphere

Energy conditions from entanglement-glue duality

One of the great conceptual insights in the research of quantum gravity of the recent 5 years or so was the realization that the geometric connection of two regions of the spacetime – according to a theory that respects the postulates of quantum mechanics and allows the spacetime to be curved, too – is physically equivalent to the entanglement between the degrees of freedom that lived in these previously separated regions of the spacetime geometry.

Folks like Mark Van Raamsdonk deserve to be credited for the original discovery of this broader concept. The Maldacena-Susskind ER-EPR correspondence is a particular, simple, well-defined example of the general concept. It claims that the Einstein-Rosen bridge – more generally, a non-traversable wormhole which is a pair of two black holes whose interiors are connected or identified – is equivalent to two perfectly entangled black holes. A high degree of entanglement is capable of changing the "most useful" spacetime topology used to describe the situation. But the spacetime topology itself isn't a well-defined or unique observable on the Hilbert space – it is emergent and one may only mention that it is "easier" to describe one situation with one topology than with another.

Because this realization is a tight link between the quantum information theory on one side; and spacetime geometry within a gravitating quantum theory on the other side (on both sides, we have a quantum theory: we just "visualize" their Hilbert space[s] in two geometrically distinct ways), we may construct dictionaries between various rules, conditions, and concepts in quantum information theory and in general relativity.

Thursday, December 11, 2014 ... Français/Deutsch/Español/Česky/Japanese/Related posts from blogosphere

Fiat money has been a great invention

It allows accurate, impartial financial planning and makes the economy more efficient than other arrangements

The recent discussions about the Bitcoin and the gold standard have made it clear that the opposition to the fiat money is rooted in many parts of the TRF readership – I would even say that this question divides our community across the usual ideological lines.

Some Czech crown banknotes

Many of my remarks in these exchanges were enumerating the reasons why the gold or the Bitcoins couldn't be a viable replacement of fiat currencies we are using today. But now I think that it may be much more logical to try to present all my points positively – because the essential message I want to convey is positive, after all.

Net neutrality, off-topic: 60 companies including IBM, Intel, Cisco, D-Link, Qualcomm, and Panasonic NA sent a letter to the FCC opposing net neutrality. With this group, do you still misunderstand why I classify the champions of this ideology as anti-capitalist mujahideens?
So why does the society need any money? Why the fiat currencies are better than other setups? What makes a fiat currency system better than others? And why are some of the most widespread criticisms of the whole concept of fiat money unjustified and immaterial?

RealClimate's opinion on the WUWT widget

Two months ago, it has been ten years since this weblog was founded. Two months later, a group of fraudulent proponents of the climate hysteria founded RealClimate.ORG, a domain designed to spread misinformation about the climate issue.

I never planned to celebrate the 10th birthday because I find such celebrations stupid and I am shy – but if you want to drink some whiskey at home, be my guest! After these ten years, this blog run by one person (but made so inspiring and kind by many of you, thank you!) has welcomed the same number of visitors as RealClimate.ORG which is run by a dozen of folks, about 50% of the "global community" that wants to force the mankind to pay trillions of dollars. Not bad.

Congratulations to the 10th birthday of RealClimate.ORG.

Lacking the Lumoesque shyness, modesty, and focus on the beef, the RealClimate.ORG website has published not just one but three Happy 10th Birthday blog posts.

Meanwhile, their friends celebrated, too. All of them flew to Peru, Lima and set a new world record in the money wasted for a hysterical climatic conference. Their Greenpeace comrades, also in Peru, damaged and desecrated the Nazca lines by an ancient civilization that have been carefully protected for 1,500 years. (Ironically enough, the most irreversible damage has been done by the Greenpeace officials' footprints, too. The Peruvian government normally demands special shoes etc. for all the visitors.) The similarity of this vandalism to the liquidation of heritage by the Islamic State is way too obvious.

The Peruvian government is suing Greenpeace and because of the pricelessness of these geoglyphs, the Latin American nation undoubtedly has the moral right to liquidate the disrespectful terrorist organization. But my realism prevents me from believing that this outcome will actually materialize. But I want to discuss the previous RealClimate.ORG blog post – one about a... widget.

Wednesday, December 10, 2014 ... Français/Deutsch/Español/Česky/Japanese/Related posts from blogosphere

MIT's terror against Walter Lewin's lectures is unacceptable

Banned lectures and rewritten history resemble Nazism

Update: Jason seems to claim that all this MIT-wide scandal was caused by one sentence that Walter Lewin tweeted, "queefing [=vaginal farting] is yours", in a childish conversation about a plan to create a water company that two girls started with him. If true, it's quite unbelievable.
Prof Walter Lewin has been a hero of the open courses. His online MIT courses on physics – usually "rather elementary" physics – have attracted millions of viewers. You may perhaps find some cool videos on YouTube or you may directly go to an otherwise obscure backup at VideoLectures.NET.

I recommend you e.g. this lecture on mechanical energy where Lewin offered his life for the claim that the energy is conserved. He said "if I don't succeed in giving the heavy ball the zero speed, this will be my last lecture". The world is a šitty place, however, so the zero speed wasn't a sufficient condition.

Dilaton has noticed an MIT press release (see also NYT) that proudly informs that a student has complained about some online communication with Lewin. A committee has determined that he has violated a "sexual harassment" regulation at MIT.

The result? They removed all of his videos from MIT websites and declared that his title "professor emeritus" is no longer valid.