Friday, May 17, 2013

Quantum computer with no quantum speedup

MIT complexity theorist Scott Aaronson is back on the warpath against those claiming successful quantum computing:
“Look, Scott, let the investors, government bureaucrats, and gullible laypeople believe whatever they want — and let D-Wave keep telling them what’s necessary to stay in business.  It’s unsportsmanlike and uncollegial of you to hold D-Wave’s scientists accountable for whatever wild claims their company’s PR department might make.  After all, we’re in this game too!  Our universities put out all sorts of overhyped press releases, but we don’t complain because we know that it’s done for our benefit.  Besides, you’d doubtless be trumpeting the same misleading claims, if you were in D-Wave’s shoes and needed the cash infusions to survive.  Anyway, who really cares whether there’s a quantum speedup yet or no quantum speedup?  At least D-Wave is out there trying to build a scalable quantum computer, and getting millions of dollars from Jeff Bezos, Lockheed, Google, the CIA, etc. etc. to do so—resources more of which would be directed our way if we showed a more cooperative attitude!  If we care about scalable QCs ever getting built, then the wise course is to celebrate what D-Wave has done—they just demonstrated quantum annealing on 100 qubits, for crying out loud!  So let’s all be grownups here, focus on the science, and ignore the marketing buzz as so much meaningless noise — just like a tennis player might ignore his opponent’s trash-talking (‘your mother is a whore,’ etc.) and focus on the game.”

I get this argument: really, I do. I even concede that there’s something to be said for it. But let me now offer a contrary argument for the reader’s consideration. ... If that happens, then I predict that the very same people now hyping D-Wave will turn around and—without the slightest acknowledgment of error on their part—declare that the entire field of quantum computing has now been unmasked as a mirage, a scam, and a chimera.  The same pointy-haired bosses who now flock toward quantum computing, will flock away from it just as quickly and as uncomprehendingly.  Academic QC programs will be decimated, despite the slow but genuine progress that they’d been making the entire time in a “parallel universe” from D-Wave.  People’s contempt for academia is such that, while a D-Wave success would be trumpeted as its alone, a D-Wave failure would be blamed on the entire QC community.
I get the impression that there is some resentment of D-Wave's private funding. It is okay if university quantum computer researcher make wild claims, because they don't have to deliver a product. D-Wave promises a product that can be benchmarked, and subject to failure in the marketplace.

There is, unfortunately, no proof that quantum computing is possible. And it may never be. Peer-reviewed professors can live in an academic bubble, and pretend that it is possible.

The NY Times reports:
In tests last September, an independent researcher found that for some types of problems the quantum computer was 3,600 times faster than traditional supercomputers. According to a D-Wave official, the machine performed even better in Google’s tests, which involved 500 variables with different constraints.

“The tougher, more complex ones had better performance,” said Colin Williams, D-Wave’s director of business development. “For most problems, it was 11,000 times faster, but in the more difficult 50 percent, it was 33,000 times faster. In the top 25 percent, it was 50,000 times faster.” Google declined to comment, aside from the blog post.

The machine Google and NASA will use makes use of the interactions of 512 quantum bits, or qubits, to determine optimization. They plan to upgrade the machine to 2,048 qubits when this becomes available, probably within the next year or two. That machine could be exponentially more powerful.
It sounds great, but apparently there is some dispute about whether there is really some sort of magical quantum speedup.

Update: Peter Shor writes:
This [argument that an off-the-shelf classical can solve the D-Wave problem many times faster] is exactly like arguing that if you look at the Wright Brothers’ first flight at Kitty Hawk, they could have gone farther, faster, and much more cheaply if they had just used an automobile. It’s just not the right comparison. D-Wave’s money was not spent only to build this current device; you have to consider that from their viewpoint, it’s just one step on the pathway to a much more complicated and useful device.
SciAm explains:
I began by explaining the theory behind quantum computing and why they hold the promise of significantly faster processing. In essence, it relies upon the fact that whilst conventional “bits” can be 0 or 1, quantum bits (so called qubits) can be both 0 and 1 at the same time (known as superposition). If you can combine qubits (known as entanglement) you can have a system that can process values that expand exponentially with the number of qubits you entangle. As with conventional programming, these qubits are passed through various logic gates to achieve the desired results. Hence, this is known as the “gate theory” of quantum computing.
This is a convenient explanation of quantum computers, but is one that Aaronson denounces as incorrect:
I agree that thinking about the wavefunction “realistically” (as an exponentially-large classical object) seems to be a mistake that countless popular writers make, which then leads them to believe that quantum computers can solve black-box search problems instantaneously, store exponentially-many classical bits, and do other things that they’re known not to be able to do.

Thursday, May 16, 2013

Atheists trashing other religious influence

Caltech cosmologist Sean M. Carroll writes Science and Religion Can’t Be Reconciled:
Why I won’t take money from the Templeton Foundation. ...

And if anyone is tempted to award me the Templeton Prize, I will totally accept it! And use the funds to loudly evangelize for naturalism and atheism. (After I pay off the mortgage.)
So he will take Templeton money if they offer him enough. Everyone has his price, I guess.

I don't care if he wants to promote his atheist beliefs, but his attitude is not that of a cold scientist. He regularly promotes unscientific physics philosophies such as many-worlds,
string theory, and the arrow of time. That stuff is no more scientific than most of the stuff that Templeton promotes.

Another Templeton critic complains:
Tim Maudlin asks for evidence of the distorting effect of Templeton funding.

It seems to me that the enormity of Templeton funding means that religious epistemology and religious perspectives on knowledge, understanding, etc., take a very large position in analytic epistemology overall. (According to Chalmers & Bourget, over 72% of philosophers are atheists; the number of projects in religious epistemology and religiously-motivated epistemology would seem outsized, given that percentage.)
So if 72% of phulosophers are atheists, then no private foundation should do anything to decrease that percentage?

I am all in favor of separating science and religion, but I put many-world and string theory on the side of religion. There is no more evidence for those concepts than there is for astrology.

(I am not quarrelling with old understandings about he second law of thermodynamics. But Carroll goes beyond that, and speculates about time running backwards in other universes. He also says that The past and future are equally real.)

Wednesday, May 15, 2013

New book defends string theory

Peter Woit writes:
There’s a new philosophy of science book out, Richard Dawid’s String Theory and the Scientific Method
The book seems to be an elaboration of these papers, downloadable for free: Underdetermination and Theory Succession from the Perspective of String Theory, On the conflicting assessments of the current status of string theory, and Realism in the age of string theory.

The argument is that a lot of big-shots work on string theory, so it must be science. The theory is unique because it claims to explain everything, while actually explaining nothing. Since the theory cannot be tested, we have to accept new definitions of science and realism. Some really smart people have opinions about what is aesthetically pleasing, and that can substitute for experiment.

Yes, that's it. He is trying to promote string theory, but his empty argument show that the theory is a failure by any objective standard.

Lumo adds:
The three reasons behind the near-certainty about the theory's validity are:
the non-existence of alternatives ...

Concerning the first argument, it is the actual explanation why the top bright theoretical physicists focus this high percentage of their intellectual skills on string theory. They simply divide their mental powers to all promising ideas, with the weight given by the degree to which they are promising. Because one may approximately say that there aren't any other promising "big ideas" outside string theory, people can't work on them.
So if these super-smart guy had a mystical belief in unicorns or astrology, and string theory were perceived as better than the alternatives for the purpose, then they study string theory. The problem with this argument is that there is no good reason to believe in unified field theory, and no good reason for believing that string theory would be progress towards that end.

Monday, May 13, 2013

Discovery of the electromagnetic Lagrangian

Lumo writes:
Schwarzschild is most famously associated with the first nontrivial exact solution to Einstein's equations of general relativity. But he would also study optics, photographic materials, celestial mechanics, quantum theory, stellar structure and statistics, Halley's comet, and spectroscopy. According to Wolfgang Pauli, Schwarzschild was the first man who wrote the correct form of the action for the electromagnetic field coupled to charges and currents.
I was surprised to learn that last Schwarzschild discovery a couple of years ago.

In my my book, I argue that the heart of special relativity was the 1905 discovery of the Lorentz covariance of Maxwell's equations.

Lorentz had a cruder concept in 1895 that he called the theorem of corresponding states. Einstein's 1905 paper postulated what Lorentz proved, but did not have the covariance concept. Poincare's 1905 paper presented the concept, and everyone else got it from him. It was not independently rediscovered by anyone else.

For one proof, Poincare presented a Lorentz invariant Lagrangian density that implies Maxwell's equations. The covariance follows from the invariance of the Lagrangian. I was going to credit Poincare with discovering the Lagrangian himself, but in researching the point for my book, I discovered that Karl Schwarzschild published it in 1903. Schwarzschild did not know that it was Lorentz invariant, or figure out the significance for special relativity, as Poincare did. Minkowski was one of the few people who grasped the significance of what Poincare did, and popularized the 4-dimensional geometrical view in 1908. Einstein was slow to understand Minkowski, but eventually caught to to what relativity was about in 1909.

Einstein's famous 1905 paper is one of the most widely praised scientific papers ever written, but it did not have the Lorentz group, spacetime, 4-dimensional geometry, relativistic Lagraangian, electromagnetic covariance, or gravitational implications. We got all those things from Poincare, and Poincare announced his results in 1905 before Einstein submitted his famous paper.

Wednesday, May 8, 2013

Why we have free will

I attacked Jerry Coyne for his unscientific views about free will. I would not bother with him, except that he is a famous and distinguished U. Chicago professor, and he posts daily about the superiority of evolutionary science to religion. He now writes:
Now most of us think that the notion of “free choice,” as in the sense of “could have chosen otherwise at a given moment,” is wrong. Excepting quantum mechanics — whose effects on behavior are unknown, and whose pure indeterminacy doesn’t fit most people’s idea of ‘ “free will” — our behaviors are determined by physical laws, and can’t be overridden by some spirit in the brain. Ergo, as Jeff said, libertarian free will is dead. I think that nearly all of us agree.
The laws of quantum mechanics are the most basic physical laws we know, and are essential to much of what we know about DNA and other microscopic aspects of life. It is crazy to say that "Excepting quantum mechanics ... our behaviors are determined by physical laws". He is saying that there is no free will (and hence no need for religion) because physical laws are deterministic except where they are not deterministic.

He then challenges:
For compatibilists:

1. What is your definition of free will?

2. What is “free” about it? Is someone who kills because of a brain tumor less free than someone who kills because, having been brought up in a terrible environment, he values drugs more than other people’s lives?

3. If humans have free will, do other species as well? What about computers?

4. Why is it important that you have a definition of free will rather than discarding the concept completely in favor of something like “agency”? That is, what “new knowledge”, as Jeff noted, does your concept add beyond reassuring people that we have “free will” after all?
A reader answers:
Definition of “free”, from OED:
“able to act or be done as one wishes; not under the control of another”

Definition of “will”, from OED:
“the faculty by which a person decides on and initiates action”

Combine the two ultra-standard definitions of the two words and you have a pretty good approximation of my definition of free will.
Free will is how conscious beings describe the choices they make in their everyday lives. Maybe dogs are conscious and maybe computers will be someday. Consciousness is harder to define.

The concepts of free will and causality are central to how we understand the world, how we organize a civilized society, and how we have purpose to our lives. I cannot disprove superdeterminism, so you are free to believe that if you wish, but it is about as silly as believing in solipsism or that we are just simulations in the Matrix.

Coyne goes on to argue that criminals are not morally responsible for their crimes, that religion is invalid, that we should have same-sex marriage, and other political views. All from a misunderstanding of quantum mechanics!

Scott Aaronson writes:
As it happens, I’ve been working on and off for the past two years on a huge essay setting out my thoughts about free will and predictability — and the essay will be online in just a week or two!
I will reserve judgment until I see his essay.

Update: A Wikipedia article on Two-stage model of free will explains how free will can be compatible with physical law.

Monday, May 6, 2013

Modern physics is not crummy

I am unhappy with this new podcast: Live From NECSS With Jim Holt On Why Does the World Exist?

Holt is a fine science journalist, and most of the discussion was about silly and unanswerable philosophical questions. But I believe he also painted a seriously inaccurate picture of modern physics.

He said that the universe is so "crummy", "not elegant", with "60+ elementary particles", 110 elements, and the "standard model is so ugly". [at 15:00] The argument is that God should have been able to create a simpler design.

This is wrong. The standard model is quite elegant. All matter is made of quarks and electrons, with energy being transmitted by bosons. You can only get to 60+ particles if you count colors, flavors, anti-particles, etc as separate particles. I still don't know how you get to 60 unless you also include supersymmetric and other fictitious particles.

The second wrong opinion is that it is "impossible to give a realistic interpretation of quantum theory", and "impossible to make sense of it", with the obligatory R.P. Feynman quote. [at 33:20]

There are textbook explanations of quantum mechanics that make perfect sense, and that has been true since about 1930. There are people who claim that it would make more sense with hidden variables or parallel universes or other such nonsense, but they have been proven wrong for 80 years. Lee Smolin is a recent example.

Yes, I know that Feynman said that quantum mechanics is hard to understand, and that is true if you want to relate it to everyday macroscopic experience. But you can understand the theory by just reading Feynman's textbook.

MIT physicist Alan Lightman reviews Smolin's book in the NY Times:
He rightly remarks that Einsteinian physics frames time as a relative concept in which the line between past and future varies with the observer. ...

Twentieth-century physics has brought us two kinds of strangeness: strange things we more or less understand, and strange things we do not understand. The first category includes relativity and quantum mechanics. Relativity reveals that time is not absolute. Clocks in relative motion to each other tick at different rates. We don’t notice relativity in daily life because the relative speed must be close to the speed of light before the effects are significant. Quantum mechanics presents a probabilistic picture of reality; subatomic particles act as if they occupy many places at once, and their locations can be described only in terms of probabilities. Although we can make accurate predictions about the average behavior of a large number of subatomic particles, we cannot predict the behavior of a single subatomic particle, or even a single atom. We don’t feel quantum mechanics because its effects are significant only in the tiny realm of the atom.
I know what he is trying to say here, but this is wrong. Relativity does not deny absolute time. When cosmologists say that the age of the universe is 13.8B years, they are using absolute time. We can distinguish the past from the future. Clocks don't tick at different rates; they only appear that way to certain observers. We can see relativistic effects in the form of magnetism.

Probability is not essential to quantum mechanics. We can apply the theory to predict the behavior of single atoms. We can say what will happen if it is struck by a photon or electron, and we can say how it can bind with other atoms. We feel quantum effects all the time. In just reading this text, your eye is detecting individual photons.
The category of strange things we do not understand includes the origin of the universe and the nature of the “dark energy” that pervades the cosmos. Over the last 40 years, physicists have realized that various universal parameters, like the mass of the electron (a type of subatomic particle) and the strength of the nuclear force (the force that holds the subatomic particles together within the centers of atoms), appear to be precisely calibrated. That is, if these parameters were a little larger or a little smaller than they actually are, the complex molecules needed for life could never have formed. Presumably, the values of these parameters were set at the origin of the universe. Fifteen years ago, astronomers discovered a previously unknown and still unexplained cosmic energy that fills the universe and acts as an antigravity-like force, pushing the galaxies apart. The density of this dark energy also appears to be extraordinarily fine-tuned. A little smaller or a little larger, and the life-giving stars would never have formed.
We know a lot about the nature of dark energy. We know the pressure and the density, we know that it is appears to be uniform (and Lorentz invariant) thru-out the universe, we know its history since the big bang, and we know how it continues to expand. Or at least we think that we know. And the dark energy is not finely tuned. If it were, then it would have been discovered much more than 15 years ago, as it would have been a consequence of the existence of stars.
He goes on to propose a variety of revolutionary ideas to codify further his notion of “real time.” In one, he suggests that every atom in the universe is causally connected to every other atom in the universe, no matter how many light-years away. According to his notion, the failure of standard quantum mechanics to predict the behavior of individual atoms arises from the fact that it does not take into account the vast numbers of interconnections extending across the universe. Furthermore, this picture of the cosmos requires an absolute time (in violation of relativity), which he calls “preferred global time.”

One of Smolin’s most astonishing ideas is something he calls the “principle of precedence,” that repeated measurements of a particular phenomenon yield the same outcomes not because the phenomenon is subject to a law of nature but simply because the phenomenon has occurred in the past. “Such a principle,” Smolin writes, “would explain all the instances in which determinism by laws work but without forbidding new measurements to yield new outcomes, not predictable from knowledge of the past.” In Smolin’s view such unconstrained outcomes are necessary for “real” time.
This is kooky. I have not seen the book, so I don't know if it is as bad as it sounds.

Friday, May 3, 2013

Impossibility of time travel

The recent Rupert Sheldrake on "Science Set Free" podcast interviews a scientist with crackpot ideas. His excuse is that Thomas Kuhn discovered that science was about groupthink, and not truth. A comment defends pursuing untestable ideas because string theory is not testable either.

Here is a poll of philopher beliefs, but it does not directly ask about Kuhn's paradigm shift theory.

Speaking of crackpot ideas, Scott Aaronson's new book defends time travel:
Yes, the Grandfather Paradox has often been put forward as a “proof” that time travel into the past is logically impossible. But there are several loopholes in that “proof.” One of them is the possibility of resolving the paradox probabilistically or quantumly (as Deutsch proposed). Another loophole is that maybe Nature simply always finds a consistent deterministic evolution, no matter how unlikely it seemed a priori. (E.g., if you went back in time and tried to kill your grandfather, you’d always discover that the gun jammed, or you forgot to load it, or he recovered from the gunshot wound and went on to sire your parent, etc. etc.) So really the Grandfather Paradox should be seen as a central, obvious difficulty that any account of closed timelike curves needs to overcome.

Your resolution of the paradox, in your first comment, is actually a good way to describe or visualize what happens in Deutsch’s resolution. (Indeed, since Deutsch avidly believes in the Many-Worlds Interpretation, he would regard it not just as a convenient way to visualize, but as a literal description of what happens in his proposal.)

However, one can also invent more complicated time-travel scenarios: for example, what happens if you flip a fair coin, and go back in time and kill your grandfather if and only if the coin lands heads? The beauty of Deutsch’s proposal is that it gives you an automatic way to compute a consistent story for any possible such scenario.

(Spoiler alert: in the above example, the solution is that you’re born with probability 2/3 and not born with probability 1/3. Or if you prefer, you’re born in 2 of 3 parallel universes, and not born in 1 of them.)
This is pretty wacky. I say that the Grandfather Paradox disproves time travel.

Here is a completely separate proof that we will never see time machines. If some future advanced civilization ever got time machines, then surely someone would decide that they are a really bad idea, and go back in time to kill the first inventor before he can create a time machine.

If you believe in Many-Worlds, then I suppose a time machine could take you to a parallel universe. But Many-Worlds is another crackpot idea with no scientific merit.

Frank Wilczek is promoting time crystals. These are not as crazy as time machines, as you cannot use them to violate logic and physics laws.

Friday, April 26, 2013

Science cannot rule out free will

Leftist-atheist-evolutionist professor Jerry Coyne blogs frequently about the evils of religion and the superiority of science, and one of his favorite arguments is to attack free will:
Al-Khalili seems to be a compatibilist — that is, he seems to find physical determinism compatible with free will, though he sees quantum mechanics as throwing a wrench into the determinism. I agree: if we reran the tape of the universe, or even the tape of life, I think things would come out differently, for in the origins of the universe, and probably in the origins of new species, true quantum indeterminism plays a role. In the case of life, for instance, it may have a hand in the production of mutations, which are the very fuel of evolution.

But Al-Khalili, unlike some other compatibilists, doesn’t see quantum indeterminacy as rescuing free will. And I don’t think others, do, either—even if that indeterminacy plays out in our brains so that at any given moment we could equally well make either of two decisions. That kind of “quantum” free will is based on pure physical randomness and, to paraphrase Dan Dennett, “is not the kind of free will worth wanting.”

No, Al-Khalili finds free will elsewhere: in unpredictability. That is, our brains are incredibly intricate—they contain roughly ten billion nerve cells, each cell connected to others through about 10,000 synapses (cell-to-cell connections made via chemical or electrical stimuli) — so predicting how a series of environmental inputs will result in a given behavioral output — a decision — can often be impossible. ...

Chaos theory, of course, is deterministic: it’s a theory that simply says that very slight alterations in the initial conditions of a complex system (say, weather patterns) can lead to very different outcomes (whether you get a hurricane). It’s all deterministic, playing out through the non-quantum laws of physics. It’s just that, like the three-body problem, we don’t know enough to work out such systems from first principles.

What baffles me is how you can derive “free will”, if that term has any meaning, from unpredictability. Yes, we can’t predict our decisions, but they still are, according to Al-Khalili, determined by the laws of physics. How does that add up to “freedom” in any meaningful sense? His statement that the choices are “real” choices is ambiguous.
Coyne's argument is essentially that whether the laws of physics are deterministic, chaotic, or random, there cannot be free because all possibilities are contrary to free will.

Ignoring his politics, philosophy, and theology, his physics is wrong. Quantum mechanics teaches that electrons have free will. Physics do not agree on the Interpretations of quantum mechanics, as different philosophies are possible. But there is certain no scientific evidence for ruling out free will.

Wednesday, April 24, 2013

Maybe no mathematical double of the universe

Peter Woit trashes a new book by physicist Lee Smolin, and quotes Smolin saying:
The most radical suggestion arising from this direction of thought is the insistence on the reality of the present moment and, beyond that, the principle that all that is real is so in the present moment. To the extent that this is a fruitful idea, physics can no longer be understood as the search for a precisely identical mathematical double of the universe. That dream must be seen now as a metaphysical fantasy that may have inspired generations of theorists but is now blocking the path to further progress. Mathematics will continue to be a handmaiden to science, but she can no longer be the Queen.
I doubt that I will agree with Smolin's main claims, but I do agree that it is a mistake to believe that physics should be a precisely identical mathematical double of the universe. My FQXi essay explains why.

An Amazon review says:
But it was much worse than that when I realized that the author was leading up to a type of "hidden variables" interpretation of Quantum Mechanics (QM). If you don't know what that term means, don't worry about it, it is just physics jargon for theories that try to replace QM by deterministic approaches that avoid the probabilistic interpretation of it. Based on personal philosophy and even religion, countless people (many of them very prominent physicists themselves) objected to the standard probabilistic interpretation of QM in the last 90 years. Hundreds of alternative deterministic approaches were proposed to replace QM. These theories are termed "hidden variable theories." The better ones actually reproduce most of the predictions of QM. But no hidden variable theory has ever produced identical results to QM for all test cases. When the differences arose in predictions, the experiments backed the predictions by QM irrefutably. As of today, there is not one single hidden variable theory that produces the same results as QM for all experiments. It may yet happen some day, but based on how hard some of the smartest people on Earth have tried and failed for 90 years (including most notably Albert Einstein) to make hidden variable theories work, the prospects are rather dim.

As if that was not bad enough, in the last few chapters the author rejects the concept of "identical particles" in QM.
I haven't seen the book, but pursuit of hidden variable theories is severely misguided, as I have argued here, and criticized Smolin here.

Lubos Motl calls the book An incredible pile of unscientific gibberish. Motl also trashes Aaronson's book here and here, and if you just read those posts, you would get the impression that Motl has a very low opinion of Aaronson. See also the comments, which did not display in my preferred browsers. No, those posts are only mild criticisms compared to the venom for Smolin.

Aaronson is really a smart theoretical computer scientist with a warped view of physics. I am sure that his book is mostly correct, even if it is over-enthusiastic about some ideas. But Smolin subscribes to a philosophy that is antagonistic to modern science. Smolin once gave this definition of science:
Science is not about what's true, or what might be true. Science is about what people with originally diverse viewpoints can be forced to believe by the weight of public evidence.

Sunday, April 21, 2013

Failing to make the inductive leap

Science writer George Johnson raves about The Best Science Book Ever Written, and adds:
Meanwhile I was reminded of a remarkable section in Judson’s The Eighth Day of Creation where he recreates, through Franklin’s journal and other sources, what she knew and when she knew it, every step along the way. He writes of her “grievous slowness of intuitive response,” of her working “head down and doggedly, ingeniously struggling in the wrong direction.” “It is easy to feel great sympathy with Franklin,” he concludes. “The fact remains that she never made the inductive leap.”
Rosalind Franklin did extremely important research on the structure of DNA. She discovered that DNA was a helix with the backbones on the outside, she specified the water content of DNA, and she did the crucial experiment with X-ray crystallography. According to Watson's 1968 memoir, The Double Helix, he and Crick made essential use of her work without her knowledge or permission, and they would have been helpless without it. Their famous 1953 papers avoided explaining how they got their DNA model and gave the false impression that Franklin's work was only to verify what Crick and Watson had already done. The 1962 Nobel Prize went to Crick, Watson, and another guy who hated Franklin and schemed to devalue what she had done. As of last year, Watson was still badmouthing Franklin.

Some people say that Franklin has been maligned because she was a woman. I don't buy it. Lots of women are properly credited. That does not explain why a well-regard science history book would say something so foolish as, “The fact remains that she never made the inductive leap.”

Whatever she may have failed to do is irrelevant to crediting her for what she did do. Her contributions are documented, and there is no dispute about what she did, as far as I know.

Einstein would never be credited for relativity if he were criticize for failing to make the inductive leap. He completely missed the most essential parts of the theory, such as the spacetime geometry and the electromagnetic covariance, and did not understand these concepts were published by others.

Update: Johnson posted a followup, drawing this comment:
Franklin deserved credit for the discovery of the structure of DNA to the degree that a lab tech deserves authorship on a paper. She did essential work that produced the breakthrough. Having said that, she did not make the intellectual breakthrough, and she did not take part in making the intellectual breakthrough. Anyone saying that she deserves to be treated on the same basis as Crick and Watson is doing so for non-scientific reasons - transparently non-scientific reasons. Franklin did excellent lab work. She failed to understand the product of that work. Crick and Watson did. She-would-have, she-could-have hypotheticals are good for novels, but for history, not so much.
I cannot explain this antagonism against Franklin. The annotated Watson Crick paper says:
(5) Here, the young scientists Watson and Crick call their model “radically different” to strongly set it apart from the model proposed by science powerhouse Linus Pauling. This claim was justified. While Pauling’s model was a triple helix with the bases sticking out, the Watson-Crick model was a double helix with the bases pointing in and forming pairs of adenine (A) with thymine (T), and cytosine (C) with guanine (G).
Watson-Crick got that double helix and inward bases from Franklin.

Thursday, April 18, 2013

Physicists in a groupthink bubble

The distinguished physicist Philip Anderson reviews a biography of Freeman Dyson:
But we did not meet until the first energy crisis, when we both attended a workshop on energy that was sponsored by the American Physical Society. Afterwards, we met at disarmament seminars at Princeton University in New Jersey, which is where I first sensed his ambiguity about conventional liberal positions on subjects such as the "Star Wars" defence initiative – most of which I hold unambiguously. ...

Most recently he has delighted in maintaining minority views on a number of topics such as climate, religion (his Christianity places him in the minority for his profession) and genetic modification.
Dyson is a liberal Democrat, and yet Anderson finds a way to criticize him for not being politically correct on all issues.

Dyson and Anderson are two of the most accomplished living 20th century theoretical physicists. This review gives a glimpse of how we might compare them. What I get out of this is that academic physicists live in a leftoid groupthink bubble, with very little deviation tolerated. Why does Anderson have to tell us that he holds conventional liberal positions unambiguously? Is he worried that his fellow might think that any reviewer should distance himself from Dyson's politics? He sounds like a Commie who might say, "I did not deviate from Kremlin policy, and you cannot trust those who do."

My guess is that a physicist would really be an outcast if he endorsed a Republican. While physicists are entitled to their political opinions, of course, it shows that the field is intolerant of critical thinking. They are not experts on global warming, but Anderson has to denounce "Dyson's dreadful misjudgment on the climate question".

Peter Woit explains how Anderson invented the Higgs mechanism, but the high-energy physicists do not like to credit him because of his role in the Democrat cancellation of the Texas Superconducting Super Collider.

Tuesday, April 16, 2013

Electrons have free will

The free will theorem of John H. Conway and Simon B. Kochen says under basic quantum postulates, electrons have free will if humans do. Here is a new interview on it:
Schleicher: Could you make a simple statement about what exactly, or intuitively, the Free Will Theorem says?

Conway: Yes. [Throws a piece of paper.] I just decided to throw that piece of paper on the floor. I don’t believe that that was determined at the start of the big bang, 14 billion years ago. I think it’s ludicrous to imagine that the entire development of the universe, including, say, this interview, was predetermined. For the Free Will Theorem, I assume that some of my actions are not given by predetermined functions of the past history of the universe. A rather big assumption to make, but most of us clearly make it. Now, what Simon and I proved is, if that is indeed true, then the same is true for elementary particles: some of their actions are not predetermined by the entire past history of the universe. That is a rather remarkable thing.

Newton’s theory was deterministic. In the 1920s, Einstein had difficulties believing that quantum mechanics was not deterministic. That was regarded as a defect of quantum mechanics. Certainly when I tried to learn quantum mechanics and didn’t succeed, I thought it was a defect. It’s not a defect. If the theory could predict what one of those particles could do, then that theory would be wrong, because, according to the Free Will Theorem — supposing we do have free will — a particle doesn’t make up its mind what it’s going to do until it does it or until shortly before it does it.

Let me describe the theorem this way. Suppose there is only a very tiny amount of free will in humans: you can press either button A or button B in a manner that is not predetermined. That is a very tiny part of what we normally consider free will for humans. And if we have that tiny amount of free will, so do the elementary particles, in a sense that a particle in response to some experiment can choose which path, C or D, that it follows. It has free action. It chooses C or D in a manner that is not a predetermined function of all the information in the past history of the universe. Schleicher: You believe that humans have free will. Conway: I do. Strict determinism tells us that all of our actions are predetermined by the past history of the universe. I don’t know, maybe it is. I can’t disprove it. I can prove that I can’t disprove it. I can prove that you [points to Schleicher] can’t disprove it either. But I believe anyway that humans have free will.

Schleicher: That is your belief.

Conway: And it is very strong. If you or somebody else doesn’t believe this, I am not going to argue with you, because I know that I can’t disprove the determinist’s position. After giving lectures on this subject in various places, sometimes I have asked whether there were any determinists in the audience. Usually in an audience of a hundred, twenty people put their hands up. They are usually among the most intelligent members of the audience, because it takes some intelligence to disbelieve something that everybody else feels is obvious or to believe something that everybody else feels is ludicrous. Several times people have come up to me and told me they were determinists and expected me to argue the matter. But since I’ve proved that nobody can disprove determinism, what is the point in trying to disprove determinism? I have no argument with determinists or, I should have said, I have no arguments with determinists.

Schleicher: The usual interpretation of quantum mechanics is that the behavior of the elementary particles is simply random.

Conway: You know, randomness doesn’t help. If the action of each particle were a predetermined function of its past plus a random string of bits, then we might as well suppose that this string of bits was produced just before the universe was created, and this is excluded just as well as totally deterministic behavior.
I would phrase it differently, because "free will" is one of those terms that drives philosophers nuts. But his theorem is correct, and restates longstanding understandings of quantum mechanics. Einstein's ideas about determinism are contrary to quantum mechanics, and so are various naive ideas about randomness. Saying that nature is deterministic or random are both very misleading, at best.

Thursday, April 11, 2013

Popper misquoted Einstein

The Indian physicist G. H. Keswani pointed out in 1965 that Poincare never credited Einstein for relativity, and argued that Lorentz and Poincare should be credited for their contributions. This prompted immediate rebuttals by Dingle and Popper. The exchange is summarized here. (See also I, III, reply, reply, "LTE" = Lorentz Transformation Equations)

Popper wrote:
Lorentz and Fitzgerald thought that the contraction of measuring rods is caused by the movement of matter through the ether, ...
Einstein suggested that the contraction is a question of "perspective" rather than a physical contraction in the moving system, and that it is mutual.
Here is what Lorentz said in 1895:
§ 91. As strange as this hypothesis would appear at first sight, nevertheless one must admit that it's not so far off, as soon as we assume that also the molecular forces, similarly as we now definitely can say it of the electrical and magnetic forces, are transmitted through the aether. If this is so, then the translation will change the action between two molecules or atoms most likely in a similar way, as the attraction or repulsion between charged particles. Now, since the shape and the dimensions of a fixed body are, in the last instance, determined by the intensity of the molecular effects, then also a change of the dimensions is inevitable.
Even tho Popper belittles it, this is a brilliant and correct statement. People knew that matter was made of atoms, but the atoms could have been solid objects in physical contact with each other. In fact, they are held together by electromagnetic forces, just as Lorentz predicted.

Karl Popper was a very famous and well-respected philosopher, but his defense of Einstein is based on misquoting him. Einstein never said that the contraction is a question of "perspective". You can check Einstein's famous 1905 paper for yourself. You will not find the word "perspective", and you will not find any disagreement with Lorentz's views. Einstein gave dozens of interviews all his life about how he (supposedly) discovered relativity, and while he acknowledged having read that 1895 Lorentz paper, he never denied that the contraction was a physical contraction.

There are a lot of Einstein idolizers who argue at great length that Einstein's 1905 view was somehow different from Lorentz's, but those arguments are never based on what Einstein actually says. Since Einstein spent a lot of time and effort into trying to explain the merits of his relativity work, it is a strange to claim that he had some view that he never claimed himself.

Einstein was a patent examiner. They are trained to separate work from what went before, and to judge an inventor's originality by his own claims. Inventors only get credit for what they claim for themselves.

Popper says:
Though Einstein appears to have known Poincaré's Science and Hypothesis prior to 1905, there is no theory like Einstein's in this great book. Einstein could not have known Poincaré's article of 1905; and even in this article there is only a most inspiring programme sketched for a relativity theory -- not the theory itself.
Poincare's 1902 book was written for the general public, and does not have any equations. It explains the principle of relativity, and denies the aether, but does not flesh out the theory, as Popper says. Poincare's 1905 article was really two articles -- a 5-page summary and a 50-page detailed paper. Einstein certainly could have known about Poincare's summary as it was published and delivered to Einstein's library three weeks before Einstein submitted his own 1905 relativity paper.

Popper was wrong to say that Poincare's 1905 paper was only a sketch and not a theory. Poincare had concepts like 4-dimensional spacetime geometry and covariance of Maxwell's equations, and these went way beyond what Einstein did.

Herbert Dingle was not so respected:
Ultimately Dingle re-focused his criticism to claim that special relativity was logically inconsistent: "The theory [special relativity] unavoidably requires that A works more slowly than B and B more slowly than A -- which it requires no super-intelligence to see is impossible."
This is indeed a paradox, but Poincare and Minkowski proved that there is no logical inconsistency, by showing that the Lorentz transformations form a group preserving a geometric structure.

Popper has his critics also. A recent paper by Alan B. Whiting argues that in "his most famous work he displays misunderstandings of science and mathematics at a basic level." Popper understood science much better than most philosophers, but maybe that is not saying much.

Much of this is explained in How Einstein Ruined Physics.

Wednesday, April 10, 2013

New Poincare biographies

A biography was published last year, titled: Henri Poincaré: Impatient Genius:
This book describes the life and work of Henri Poincaré, detailing most of his unique achievements in mathematics and physics. It is divided into two parts—the first on Poincaré’s life, and the second on his contributions to the mathematical sciences. Apart from biographical details, attention is given to Poincaré’s results on automorphic functions; differential equations and dynamical systems; celestial mechanics; mathematical physics, in particular the theory of the electron and relativity; and topology (analysis situs). A chapter on philosophy explains Poincaré’s conventionalism in mathematics and his view of conventionalism in physics. The book shows how Poincaré reached his fundamentally new results in many different fields, how he thought about problems, and how one should read his work. Simultaneously, it is made clear how analysis and geometry are intertwined in Poincaré’s thinking and work. In dynamical systems, this becomes clear in his description of invariant manifolds, his association of differential equation flow with mappings, and his fixed-point theory. There is no comparable book on Poincaré presenting such a relatively complete vision of his life and the working of his very original mind. Scientists and engineers as well as general readers interested in the history of science will find this book of interest. Reviews of this book:"The title of this biography is particularly well chosen : Henri Poincaré was a true genius, and he was impatient. It gives a fair picture of both the man and the scientist, completed by particularly well chosen illustrations. Jean Mawhin, Université Catholique de Louvain, Belgium "Ferdinand Verhulst has written a true scientific biography, introducing Poincaré the man, his cultural milieu, and his mathematics. This book shows why, a century after his death, Poincaré's ideas still shape a substantial part of the mathematical sciences." Philip J Holmes, Princeton University, USA
The discovery of relativity is considered one of his minor accomplishments.

Albert Einstein is considered the greatest genius who ever lived, primarily for his 1905 relativity paper. But he got the Lorentz transformations, constancy of the speed of light, local time, relativistic mass, and theorem of corresponding states from Lorentz, and the relativity principle, clock synchronization method, and E=mc2 from Poincare. Meanwhile, Poincare's 1905 relativity paper discovered the Lorentz group, covariance of Maxwell's equations, spacetime geometry, and relativistic gravity. Einstein completely missed these points, and did not even understand them until years later. Today relativity is taught based on Poincare's ideas.

The biography says:
The main priority controversy regarding the new mechanics, replacing Newtonian classical mechanics by relativity, is over special relativity, with prominent candidates Einstein, Lorentz, and Poincaré. [p.62] ...

In this respect, it is difficult to understand why Einstein, when describing the development of relativity in 1949 [Einstein 1950], mentions many scientists, in particular Lorentz, but omits Poincaré. [p.64]
That is a polite way of saying that Einstein lied about the relativity story all his life. The obvious answer is that there was nothing that Einstein could have said about Poincare without diminishing his own status. He could not get away with saying that Poincare's work was deficient, or wrong, or unknown, or not influential, or not original, or anything like that. He just had to pretend that it did not exist.

Another biography last year was Henri Poincaré: A Scientific Biography. A recent AAAS Science magazine review (behind a paywall) says:
Despite his many brilliant interventions and mathematical virtuosity, Poincaré, Gray argues, made no great discovery in physics. Nonetheless, Gray emphasizes that for Poincaré “there is no valid or clear distinction to be made between mathematics and physics because the two are so intimately entangled.”
The book seems to take the view that Poincare's discovery of special relativity as spacetime non-Euclidean geometry was a mathematical discovery, not a physical one, and it was perfected by Minkowski, not Poincare or Einstein. The book says:
He [Poincare] preferred a theory in which space and time were separate and Lorentz contractions really occurred, and argued, quite correctly, that because there could never be conclusions on this view that were incompatible with conclusions derived from a theory of space-time it was simple a matter of convenience which theory was adopted. [p.529]
The book also discusses Poincare's many contributions to celestial mechanics and quantum mechanics.

Tuesday, April 9, 2013

No randomness on the fly

The MyCQstate blog gives a nice summary of attempts to use entanglement for cryptography, and
explains:
This credo is best exemplified by the use of entanglement in quantum information: ... This paradigm shift ...

This semester (or what remains of it) at MIT I am organizing a small reading group whose focus will be the study of entanglement as a resource for cryptography. ...

Bell identified the following three reasonable assumptions, that I’ll refer to as in the following:

1. Measurement independence (“free will”):...
2. No-signaling (“no violation of special relativity”): ...
3. Outcome independence (“local realism”):...

Although it was explicitly made only relatively recently (see Chapter 5 in Roger Colbeck’s 2009 Ph.D. thesis), the sole violation of any Bell inequality already has one striking consequence: any physical process whose input/output behavior generates said violation cannot by definition satisfy all three basic assumptions . Provided that we believe in free will (inputs in the experiment are chosen independently of the system’s internal state) and e.g. special relativity (as a way to enforce the no-signaling condition between the system’s two parts), then I claim that the physical process — whatever it is, quantum mechanical or not — must generate randomness on the fly.
Random numbers are useful in cryptography, so if quantum mechanics can find a way to generate and transmit randomness on the fly, then maybe there would be some use to cryptography.

Unfortunately no such application has been found. The problem is in the assumption of local realism, which means that observations must faithfully reflect hidden mathematical variables, and no such variables have been found. The concept of hidden variables is appealing to some people, but it is contrary to how quantum mechanics has been understood for 80 years.

Entanglement is not even necessary for quantum cryptography. See BB84 for an explanation of it without entanglement. So the emphasis on entanglement is misleading.

Quantum cryptography does not solve any problems that are not better solved with conventional cryptography, and has no practical use. The main drawbacks of quantum cryptography are its inability to use routers or provide authentication, in addition to the questionable security. I guess it is being used here as a way of explaining quantum mechanics, but even that it not correct if it is claimed that it generates randomness on the fly.