Monday, March 19, 2018

Burned books are lost

"Preposterous" Sean M. Carroll writes, in memory of Stephen Hawking:
Hawking’s result had obvious and profound implications for how we think about black holes. Instead of being a cosmic dead end, where matter and energy disappear forever, they are dynamical objects that will eventually evaporate completely. But more importantly for theoretical physics, this discovery raised a question to which we still don’t know the answer: when matter falls into a black hole, and then the black hole radiates away, where does the information go?

If you take an encyclopedia and toss it into a fire, you might think the information contained inside is lost forever. But according to the laws of quantum mechanics, it isn’t really lost at all; if you were able to capture every bit of light and ash that emerged from the fire, in principle you could exactly reconstruct everything that went into it, even the print on the book pages. But black holes, if Hawking’s result is taken at face value, seem to destroy information, at least from the perspective of the outside world. This conundrum is the “black hole information loss puzzle,” and has been nagging at physicists for decades.

In recent years, progress in understanding quantum gravity (at a purely thought-experiment level) has convinced more people that the information really is preserved.
Common sense tells us that encyclopedia information gets lost in a fire. Quantum gravity thought experiments tell theorists otherwise. Whom are you going to believe?

I believe that the info is lost. I will continue to believe that until someone shows me some empirical evidence that it is not. And there is no law of quantum mechanics that says that info is never lost.

John Preskill (aka. Professor Quantum Supremacy) says otherwise. Info can't disappear because it is needed to make those quantum computers perform super-Turing feats!

Saturday, March 17, 2018

Hype to justify a new particle collider

Physicist Bee explains how theoretical particle physicists are making a phony push for funding billions of dollars for a new collider:
You haven’t seen headlines recently about the Large Hadron Collider, have you? That’s because even the most skilled science writers can’t find much to write about. ...

It’s a PR disaster that particle physics won’t be able to shake off easily. Before the LHC’s launch in 2008, many theorists expressed themselves confident the collider would produce new particles besides the Higgs boson. That hasn’t happened. And the public isn’t remotely as dumb as many academics wish. They’ll remember next time we come ask for money. ...

In an essay some months ago, Adam Falkowski expressed it this way:

“[P]article physics is currently experiencing the most serious crisis in its storied history. The feeling in the field is at best one of confusion and at worst depression”

At present, the best reason to build another particle collider, one with energies above the LHC’s, is to measure the properties of the Higgs-boson, specifically its self-interaction. But it’s difficult to spin a sexy story around such a technical detail. ...

You see what is happening here. Conjecturing a multiverse of any type (string landscape or eternal inflation or what have you) is useless. It doesn’t explain anything and you can’t calculate anything with it. But once you add a probability distribution on that multiverse, you can make calculations. Those calculations are math you can publish. And those publications you can later refer to in proposals read by people who can’t decipher the math. Mission accomplished.

The reason this cycle of empty predictions continues is that everyone involved only stands to benefit. From the particle physicists who write the papers to those who review the papers to those who cite the papers, everyone wants more funding for particle physics, so everyone plays along.
So all this hype about multiverse, susy, naturalness, strings, etc is a hoax to get funding for a new collider?

Theoretical physics peaked in about 1975. They found the Standard Model, and thus had a theory of everything. Instead of being happy with that, they claimed that they need to prove it wrong with proton decay, supersymmetry, grand unified field theories, etc. None of those worked, so they went on to multiverse, black hole firewalls, and other nonsense.

How much longer can this go on? Almost everything theoretical physicists talk about is a scam.

Stephen Hawking was a proponent of all this string theory, multiverse, supersymmetry, black hole information nonsense. I don't think that he did much in the way of serious research in these topics, but he hung out with other theoretical physicists who were all believers.

Friday, March 16, 2018

The blockchain bubble

The Bitcoin blockchain is interesting from cryptological or computing complexity view, but it is solves a problem of no interest to the typical consumer. Other technologies are preferable for the vast majority of applications. The blockchain has become a big scam.

A new essay explains some of the problems:
While much of the tech industry has grown bearish on the volatility of cryptocurrencies, enthusiasm for its underlying technology remains at an all-time high. Nowadays we see “blockchain” cropping up with impressive frequency in even the most unlikely startup pitches. And while blockchain technology does have genuinely interesting and potentially powerful use cases, it has enormous drawbacks for consumer applications that get little mention in media coverage. ...

As it stands, blockchain is caught between three competing objectives: fast, low-cost, and decentralized. It is not yet possible to make one chain that achieves all three. Fast and decentralized chains will incur a high cost because the storage and bandwidth requirements for historical archiving will be enormous and will bloat even with pruning. Aim for fast and low-cost, and you’ll have to introduce a bank-like authority (“Tangles” are a proposed solution, but not yet fully understood).

At high volume, a good credit card processor can settle a typical $2 transaction for somewhere around $0.10. Some of the largest online game economies manage more than a million user-to-user transactions per day, instantaneously, with no fees. And yet, I can name half a dozen startups trying to inject an expensive and slow blockchain into this very problem.

Blockchain is a customer support nightmare

For most consumers, losing a password to an online service is a mild inconvenience they’ve grown accustomed to, since typically, it’s quickly fixed by requesting an email reset, say, or talking with customer service.

Blockchain wallets and their passwords, by contrast, are tied to a file on a user’s hard disk and are absolutely critical to users trying to access the blockchain. By their very nature they have no recovery mechanism. “You lose your password, you lose everything” is an awful user experience for mainstream consumers and a nightmare for companies attempting to build their service on a blockchain. If you use a hosted service, the risk of theft or sudden loss of assets is very real, with central targets and limited traceability. ...

Nothing about blockchain applications is easy for consumers right now. Everyday users accustomed to making digital and online payments would have to be trained to make blockchain purchases, learning to apply the right mix of paranoia and caveat emptor to prevent theft or buying from shady dealers. Irreversible pseudonymous transactions do not lend themselves well to trust and integrity.

Compounding this is the speed and the transaction fees involved. Most public chains have settlements measured in minutes — unless you’re willing to pay high transaction fees. Compare that to the 2-10 seconds for a saved credit card transaction customers are accustomed to in the age of fast mobile interfaces and instant gratification. ...

These points only scratch the surface of what it’ll truly take to make blockchain ready for a mass market.
The Bitcoin blockchain does have some utility for the illicit transfer of money overseas, but it is hard to think of a legitimate use for it.

IBM, big banks, venture capitalists, and others are investing 100s of millions of dollars on this. It is all going to crash, because there aren't any legitimate applications that anyone has found.

Wednesday, March 14, 2018

Hawking had opinions on the black hole info paradox

From the NY Times Stephen Hawking obituary:
The discovery of black hole radiation also led to a 30-year controversy over the fate of things that had fallen into a black hole.

Dr. Hawking initially said that detailed information about whatever had fallen in would be lost forever because the particles coming out would be completely random, erasing whatever patterns had been present when they first fell in. Paraphrasing Einstein’s complaint about the randomness inherent in quantum mechanics, Dr. Hawking said, “God not only plays dice with the universe, but sometimes throws them where they can’t be seen.”

Many particle physicists protested that this violated a tenet of quantum physics, which says that knowledge is always preserved and can be retrieved. Leonard Susskind, a Stanford physicist who carried on the argument for decades, said, “Stephen correctly understood that if this was true, it would lead to the downfall of much of 20th-century physics.”

On another occasion, he characterized Dr. Hawking to his face as “one of the most obstinate people in the world; no, he is the most infuriating person in the universe.” Dr. Hawking grinned.

Dr. Hawking admitted defeat in 2004. Whatever information goes into a black hole will come back out when it explodes. One consequence, he noted sadly, was that one could not use black holes to escape to another universe. “I’m sorry to disappoint science fiction fans,” he said.

Despite his concession, however, the information paradox, as it is known, has become one of the hottest and deepest topics in theoretical physics. Physicists say they still do not know how information gets in or out of black holes.
Not only that, but physicists do not have a sufficiently coherent definition of information in order to make this a paradox. And even if they did, there were be no way to resolve an issue about information leaking out of a black hole.

This shows the sorry state of theoretical physics, that such a non-question could be "one of the hottest and deepest topics".
As a graduate student in 1963, he learned he had amyotrophic lateral sclerosis, a neuromuscular wasting disease also known as Lou Gehrig’s disease. He was given only a few years to live.
He probably had some other degenerative disease.
Dr. Hawking was a strong advocate of space exploration, saying it was essential to the long-term survival of the human race. “Life on Earth is at the ever-increasing risk of being wiped out by a disaster, such as sudden global nuclear war, a genetically engineered virus or other dangers we have not yet thought of,” he told an audience in Hong Kong in 2007.
Mars will always be much more hostile to human life than the Earth, no matter what we do to Earth.
By then string theory, which claimed finally to explain both gravity and the other forces and particles of nature as tiny microscopically vibrating strings, like notes on a violin, was the leading candidate for a “theory of everything.”

In “A Brief History of Time,” Dr. Hawking concluded that “if we do discover a complete theory” of the universe, “it should in time be understandable in broad principle by everyone, not just a few scientists.”

He added, “Then we shall all, philosophers, scientists and just ordinary people, be able to take part in the discussion of why it is that we and the universe exist.”

“If we find the answer to that,” he continued, “it would be the ultimate triumph of human reason — for then we would know the mind of God.”
There is not any hope that string theory will do that.

Hawking's scientific reputation rests on two things: extending the Penrose singularity theorems, and arguing that quantum effects cause black holes to very slowly radiate.

The 20th century mathematics revolution

Mathematician Frank Quinn wrote in 2012:
The physical sciences all went through "revolutions": wrenching transitions in which methods changed radically and became much more powerful. It is not widely realized, but there was a similar transition in mathematics between about 1890 and 1930. The first section briefly describes the changes that took place and why they qualify as a "revolution", and the second describes turmoil and resistance to the changes at the time.

The mathematical event was different from those in science, however. In science, most of the older material was wrong and discarded, while old mathematics needed precision upgrades but was mostly correct. The sciences were completely transformed while mathematics split, with the core changing profoundly but many applied areas, and mathematical science outside the core, relatively unchanged. The strangest difference is that the scientific revolutions were highly visible, while the significance of the mathematical event is essentially unrecognized.
More of his opinions are here. This is essentially correct. Relativity and quantum mechanics radically changed physics in those decades, and math was similarly changed.

I would not say that the older physics was discarded; previous ideas about Newtonian mechanics, thermodynamics, and electromagnetism are still correct within their domains of applicability. The new physics was a revolution in the sense of a turning-around with new views that permitted understandings that were unreachable with the old views.

The essence of the math revolution was precise definitions and logically complete proofs. It was led by Hilbert and some logicians. It was perfected by Bourbaki.

Of course mathematicians used the axiomatic method since Euclid, but only in the early XXc was it formalized to where proofs had no gray areas at all. The 19c still used infinitesimals and other constructs without rigorous justification.

Quinn goes on to complain that educators are almost entirely still stuck in the previous 19c math. I would add that about 90% of physicists today are also.

Quinn goes on to relate this lack of understanding to a lack of respecte for mathematicians:
Many scientists and engineers depend on mathematics, but its reliability makes it transparent rather than appreciated, and they often dismiss core mathematics as meaningless formalism and obsessive-compulsive about details. This is a cultural attitude that reflects feelings of power in their domains and world views that include little else, but it is encouraged by the opposition in elementary education and philosophy. In fact, hostility to mathematics is endemic in our culture. Imagine a conversation:

A: What do you do?
B: I am a --- .

A: Oh, I hate that. Ideally this response would be limited to such occupations as "serial killer", "child pornographer", and maybe "politician", but "mathematician" seems to work. It is common enough that many of us are reluctant to identify ourselves as mathematicians. Paul Halmos is said to have told outsiders that he was in "roofing and siding"!
Yes, mathematicians are widely regarded as freaks and weirdos. Hollywood nearly always portrays us as insane losers. There was another big movie last year doing that.

A new paper takes issue with how mathematician Felix Klein fits into this picture:
Historian Herbert Mehrtens sought to portray the history of turn-of-the-century mathematics as a struggle of modern vs countermodern, led respectively by David Hilbert and Felix Klein. Some of Mehrtens' conclusions have been picked up by both historians (Jeremy Gray) and mathematicians (Frank Quinn).
Klein is mostly famous for his Erlangen program, an 1872 essay that modernized our whole concept of geometry. He embedded geometries into projective spaces, and then charactized a geometry by its symmetry group and its invariants.

Courant wrote in 1926:
This so-called Erlangen Program, entitled `Comparative Considerations on recent geometrical research' has become perhaps the most influential and most-read mathematical text of the last 60 years.
These ideas were crucial for the development of relativity. Lorentz had correctly figured out how to resolve the paradox of Maxwell's equations and the Michelson-Morley experiment, but what really tied the theory together beautifully was the symmetry group and the invariants, as that made it a non-Euclidean geometry under the Erlangen Program. Such thinking clearly guided Poincare, Minkowski, Grossmann, and Hilbert.

No history of relativity even mentions this, as far as I know. The historians focus on Einstein, who never seemed to even understand this essential aspect of relativity.

The above paper argues that Klein was a very modern mathematician who has been unfairly maligned by Marxist historians. Quinn was duped by those historians.

Quinn wants to distinguish 19c non-rigorous math from XXc axiomatic modern math, the Marxist historians instead distinguish Aryan math, Jewish math, Nazi math, racist math, and modern math. Klein was said to be half-Jewish.

The paper has quotes like these:
"This is compounded by a defect which can be found in many very intelligent people, especially those from the semitic tribe[;]8 he [i.e., Kronecker] does not have sufficient imagination (I should rather say: intuition) and it is true to say that a mathematician who is not a little bit of a poet, will never be a consummate mathematician. Comparisons are instructive: the all-encompassing view which is directed towards the Highest, the Ideal,9 marks out, in a very striking manner, Abel as better than Jacobi, marks out Riemann as better than all his contemporaries (Eisenstein, Rosenhain), and marks out Helmholtz as better than Kirchhoff (even though the latter did not have a droplet of semitic blood)."

"When the National Socialists came to power in 1933, [Bieberbach] attempted to find political backing for his counter-modernist perspective on mathematics, and declared both, intuition and concreteness, to be the inborn characteristic of the mathematician of the German race, while the tendency towards abstractness and unconcrete logical subtleties would be the style of Jews and of the French (Mehrtens 1987). He thus turned countermodernism into outright racism and anti-modernism."
I don't know what to make of this. No one talks this way anymore.

Sunday, March 11, 2018

Krauss is being silenced

I posted about metooing Krauss.

Jerry Coyne blogs on The Lawrence Krauss affair:
After that article appeared, I did some digging on my own, and came up with three cases that have convinced me that Krauss engaged in sexual predation of both a physical nature (groping) and of a verbal nature (offensive and harassing comments). The allegations that convinced me are not public, but the accusers are sufficiently credible that I believe their claims to be true. Further, these claims buttress the general allegation of sexual misbehavior made in BuzzFeed. In my view, then, Krauss had a propensity to engage in sexual misconduct. ...

I am taking the step of not allowing comments on this post as I don’t really want any discussion here of my position, which I’ve arrived at after long cogitation. As I said, I don’t want trial by social media, and it would be hypocritical of me to allow that here.
Popular podcaster atheist Sam Harris has canceled a live public interview of Krauss, which was supposed to be a sequel to the last one.

It is not mentioned that Krauss is now apparently happily married to one of those women he supposedly sexually harassed when he was a single man 10 years ago. [According to a comment below, Krauss was divorced 8 years ago.]

Coyne has a popular blog, and probably most of his readers think that he is gay. He denies it, but he blogs a lot about his personal life, and it is obvious that he has no wife, no girlfriend, and no kids. Furthermore, he has stereotypical gay interests in music, arts, clothing, and pets. And his political views are mostly what you would expect from a gay atheist professor.

I am not saying this to criticize, but to give background for his opinions. He does not appear to have any worries that any woman is going to metoo him.

I have no way of knowing how he has flirted with women in the past, and I don't see how it is anyone's business.

I wonder where this is going. Is the Physics community going to sit back and let their colleagues be silenced and destroyed? If he were being ostracized for being a Communist, I am sure that Krauss's colleagues would stick up for him.

Like him or not, Krauss was one of the leading figures in the public image of Physics. Where is this going? He has views which are that of a typical Trump-hating leftist professor, but that is not good enough. Maybe Physics will have to be feminized, with only feminist professors being allowed to explain Physics to the public.

Update: Coyne responds:
What? I must be gay because I’m not worried about being #MeToo’d? ...

If I could have imagined all the ways people would go after me for my stand, I would never have dreamed up this one. Thanks, Roger, for a long moment of amusement. You’re an idiot.
I did not say that he is gay. If he were, then I think that he would probably say so. The point is about ostracizing Krauss.

Update: Commenter Craw writes "Well I think Coyne has simply misread Roger’s post entirely." Coyne replies:
I understand Craw’s post perfectly. I know his point was to defend the person at issue; the part about me being gay was simply his hamhanded attempt to understand why I was part of the “pile on”. But I found that part really humorous and a complete miss on the part of the writer.

Seriously, don’t insult me by saying that I didn’t understand what was a straightforward (though incredibly dumb) post. I picked out one part to show the lengths to which people will go to get at me for what I believe.

As Dark Buzz himself says, the point was not just that people were ostracizing the person at issue (unfairly, he thinks, but he’s wrong), but also to try to understand why I was part of the “pile on”.

You’re insulting the intelligence of not just me, but of everyone here. Best to leave this topic alone and stop posting excerpts from that website here. People can go over there to read any response by this befuddled individual.
Coyne says he wanted "to show the lengths to which people will go to get at me for what I believe."!

Coyne collected some anonymous and confidential gossip about Krauss, accused him of "sexual predation" and "propensity to engage in sexual misconduct", and announced that he is publicly disassociating himself from Krauss. But I am the one who is going to lengths to "get at" Coyne?!

I like Coyne's blog. Sometimes I disagree with him. Sometimes I say so.

Tuesday, March 6, 2018

Google Bristlecone would be compelling

Google just announced a quantum supremacy chip:
This device uses the same scheme for coupling, control, and readout, but is scaled to a square array of 72 qubits. We chose a device of this size to be able to demonstrate quantum supremacy in the future, investigate first and second order error-correction using the surface code, and to facilitate quantum algorithm development on actual hardware. ...

This device uses the same scheme for coupling, control, and readout, but is scaled to a square array of 72 qubits. We chose a device of this size to be able to demonstrate quantum supremacy in the future, investigate first and second order error-correction using the surface code, and to facilitate quantum algorithm development on actual hardware. ...

We believe Bristlecone would then be a compelling proof-of-principle for building larger scale quantum computers. ...

We are cautiously optimistic that quantum supremacy can be achieved with Bristlecone, and feel that learning to build and operate devices at this level of performance is an exciting challenge! We look forward to sharing the results and allowing collaborators to run experiments in the future.
In other words, they are not quite there yet, but any day now they will be announcing a Nobel-prize-worthy computer.

I expect to be reading announcements like this for the next five years. It is like reading that high-energy particle physicists are close to discovering supersymmetry. It is all a pipe dream.

Bell tacitly assumed commuting observables

Physicist N. David Mermin just posted a revision of his 1993 paper, Hidden Variables and the Two Theorems of John Bell:
In all these cases, as Bell pointed out immediately after proving the Bell-KS theorem, we have “tacitly assumed that the measurement of an observable must yield the same value independently of what other measurements must be made simultaneously.” ...

This tacit assumption that a hidden-variables theory has to assign to an observable A the same value whether A is measured as part of the mutually commuting set A, B, C, ... or a second mutually commuting set A, L, M, ... even when some of the L, M, ... fail to commute with some of the B, C, ..., is called “non-contextuality” by the philosophers. Is non-contextuality, as Bell seemed to suggest, as silly a condition as von Neumann’s — a foolish disregard of “the impossibility of any sharp distinction between the behavior of atomic objects and the interaction with the measuring instruments which serve to define the conditions under which the phenomena appear,” as Bohr23 put it?
Yes, it is a silly condition, because it is contrary to everything we know about atomic physics. Many observables do not commute. If you want to measure position and momentum of a particle, then it makes a big difference which you measure first. That is the essence of the Heisenberg uncertainty principle.

Some people try to claim that Bell just made physically reasonable assumptions, but that is false.
To those for whom non-locality is anathema, Bell’s Theorem finally spells the death of the hidden-variables program.31 But not for Bell. None of the no-hidden-variables theorems persuaded him that hidden variables were impossible. What Bell’s Theorem did suggest to Bell was the need to reexamine our understanding of Lorentz invariance, as he argues in his delightful essay on how to teach special relativity* and in Dennis Weaire’s transcription of Bell’s lecture on the Fitzgerald contraction.** “What is proved by impossibility proofs,” Bell declared, “is lack of imagination.”
Bell has his followers today, and they still refuse to accept impossibility proofs.

Update: A reader asks me to elaborate. Check the blog for past postings on this topic, for more detail.

A core tenet of quantum mechanics is that there are no hidden variables. Von Neumann was explicit about this in his textbook from about 1930. Bell, Einstein, and other dissenters have claimed that quantum mechanics is not a realistic theory, and that only a hidden variable theory achieves the sort of philosophical realism that they aspire too. Bell devised a clever way of testing his hidden variable ideas. Experiments have proved his hidden variable theories to be wrong.

I don't think Bell or Einstein ever stopped believing in hidden variable theories. Nearly everyone else, including myself, accepts that they have been proven wrong.

Saturday, March 3, 2018

The death of supersymmetry

The Economist mag reported:
“The great tragedy of science”, said Thomas Huxley, “is the slaying of a beautiful hypothesis by an ugly fact.” That, though, is the scientific method. If nature provides clear evidence that a hypothesis is wrong then you have to abandon it or at least modify it. It is psychologically uncomfortable, no doubt, for those with an interest in the correctness of the hypothesis in question. But at least everybody knows where they stand.

What happens, though, in the opposite case: when nature fails to contradict a hypothesis but stubbornly refuses to provide any facts that support it? Then nobody knows where he stands. This is fast becoming the case for a crucial hypothesis in physics, called Supersymmetry — or Susy, to its friends. Susy attempts to tie up many of the loose ends in physical theory by providing each of the known fundamental particles of matter and energy with a “supersymmetric” partner particle, called a sparticle. It is neat. It is elegant. But it is still unsupported by any actual facts. And 2017 looks like the year when the theory will either be confirmed or dropped.
No, it was not neat or elegant.

Theorists liked it because it could be used to cancel certain anomalies. With SUSY, string theory only need 6 extra dimensions instead of 22.

The Standard Model is neat and elegant because it models the universe with only about 20 parameters. Supersymmetric models all require at least 120 extra parameters, none of which have any connection to any known observational reality.

The SUSY models thus forced a vast and unnecessary complexity. Ptolemaic epicycles made much more sense, as they were only introduced to the extent needed to explain observations.

Sabine Hossenfelder posted that naturalness is nonsense. One could believe in supersymmetry independent of naturalness, but the two concepts seem to have the same followers. They have an almost religious belief that the universe will conform to their peculiar notions of beauty. For an example of such a believer, see Lubos Motl.