Really, there’s not much more to say than that. They asked; I said I could only move if they upgraded their software to allow equation support; they said an upgrade was in the works; eventually, I decided to get situated over there so that somebody who knows how the software is meant to be used is around to get it going. These things don’t happen until somebody pushes. Like Dad always said, the bitchy wheel gets the grease.

Oh, and I figured I should profit, even if only a tiny bit, from any traffic which goes to the Carnival of Elitist Bastards.

INCIDENTALLY, if you’re looking for something to uplift your spirit, I have just been informed that the TV series Cosmos (1980) is available for sale on iTunes. I don’t have iTunes, so I can’t tell you much more than that.

Anyway, while I stuff my head with ideas I barely have the background to understand, and while I’m revising a paper so that it (superficially) meets PNAS standards, and while I try to re-learn the kinetic theory I forgot after that exam a few years back. . . Here’s a cat!

(This one is for Zeno, and was recaptioned from here.)

Let this be your BPSDB for today.

It also makes good sense to invest a serious amount of time and effort into learning any skill that you are likely to use repeatedly in the future. A good example in mathematics is LaTeX: if you plan to write a lot of papers, it makes sense to go beyond the bare minimum of skill needed to jerry-rig whatever you need to write your paper, and go out and seriously learn how to make tables, figures, arrays, etc. Recently I’ve been playing with using prerecorded macros to type out a standard block of LaTeX code (e.g. \begin{theorem} … \end{theorem} \begin{proof} … \end{proof}) in a few keystrokes; the actual time saved per instance is probably minimal, but it presumably adds up over time, and in any event feels like you’re being efficient, which is good for morale (which becomes important when writing a long paper).

The risk is that you might end up a freak like me: after you’ve defined a few macros for moments and cumulants and partial derivatives, you get bitten by a radioactive backslash key and start typing all your class notes in LaTeX while the professor is lecturing. That aside, thinking about the proper time to learn these “accessory skills” puts me in the mood for a rant. (Well, what doesn’t?)

MIT did an exasperating thing with its undergraduate physics programme shortly before my time. The way I heard the story, they’d been afraid of losing students to other majors, so they dumbed down the sophomore-year classes (virtually excising Lagrangian mechanics, for example). We were left with a “waves and vibrations” class which was rather a junk drawer of different examples; a quantum-mechanics course which lacked guts and thus forsook glory; a decent introduction to statistical mechanics; and a relativity class which, hamstrung by fear of sophistication, also suffered because it lacked a singing Max Tegmark.

Whatever the historical root cause, we were definitely ill prepared for junior year, which featured our first real term of quantum physics, along with Junior Lab, the course which (a) convinced me I should never be an experimentalist and (b) disrupted my sleep cycle enough to give me really cool alien-abduction hallucinations. Now, there’s a great deal to be said for stress-testing your students (putting them through Degree Absolute, as it were). The real problem was that it was hard for all the wrong reasons. Not only were the experiments tricky and the concepts on which they were based abstruse, but also we students had to pick up a variety of skills we’d never needed before, none of them connected to any particular experiment but all of them necessary to get the overall job done. For example: we had to pick up statistical data analysis, curve fitting and all that pretty much by osmosis: “Here’s a MATLAB script, kids — have at it!” This is the sort of poor training which leads to sinful behavior on log-log plots in later life. Likewise, we’d never had to write up an experiment in formal journal style, or give a technical presentation. (The few experiences with laboratory work provided in freshman and sophomore years were, to put it simply, a joke.) All this on top of the scientific theory and experimental methods we were ostensibly learning!

Sure, it’s great to throw the kids in the pool to force them to swim, but the water is deep enough already! To my way of thinking, it would make more sense to offload those accessory skills like data description, technical writing and oral presentation to an earlier class, where the scientific content being presented is easier. Own up to the fact that you’re the most intimidating major at an elite technical university: make the sophomore-year classes a little tougher, and junior year can remain just as rough, but be so in a more useful way. We might as well go insane and start hallucinating for the right reason.

Of course, nobody has died and made me King. (I’ve got a bottle of ear-poison; just give the word.) For the moment, I’m just an annoying guy who thinks that everybody would benefit if some priorities were shuffled around.

FOR REFERENCE:

\newcommand{\moment}[1]{\ensuremath{\left\langle
    #1 \right\rangle}}
\newcommand{\cumulant}[1]{\ensuremath{\left\langle
    #1 \right\rangle_{c}}}

Witt’s book starts with pseudomathematics before moving on to pseudophysics. As Ben explains,

Chapter 1 is where Witt lays out a series of “proofs” derived from what he calls the “Null Axiom”. That axiom is: “Existence sums to nonexistence” (pg. 28)—something that Witt calls self-evident after a page of invalid set theory. The central mistake, if I had to identify one, is the claim that “X does not exist” is the same as “everything except X exists”. This is utter baloney, whether in formal logic or in set theory or in daily experience.

Actually, as the book unfolds, Witt doesn’t appear to use this dead-in-the-water non-axiom for anything. He does, however, pile on more pseudomathematics:

Chapter 3 contains such gems as Theorem 3.1: “The Existence of Any Half of the Universe is Equal to the Nonexistence of the Other Half” (pg. 66) and Theorem 3.9: “The Time Required for Light to Traverse the Universe is Eternity, infinity/c” (pg. 72). I am not making this up. Witt throws around “infinity” as though it were an ordinary real number; he multiplies and divides by it, etc., with normal algebraic cancellation. This is complete nonsense; there are two centuries of mathematical thought figuring out the mathematical properties of infinity, and Witt’s approach is valid in exactly none of them. (Witt later explained on his online forum—currently disabled—that he’s reinvented all of the mathematics associated with “infinity”. His reasoning, if that’s what you call it, was that his new definition jibed with a grand idea about math being dependent on nature; it was an argument from incredulity.)

When Witt does finally get around to physics, five chapters into the book, he doesn’t do any better.

Witt’s entire conception of modern atomic physics is that it involves “probability clouds” designed to resolve the Rutherford catastrophe. That’s the version I learned when I was in middle school—Witt writes as though everyone else learned that too, accepted it as unthinking gospel, and built a religion around it. Did he ever notice the thousands of studies, both in physics and in philosophy of physics, discussing the plausibility or implausibility of quantum mechanics and alternatives to it? Did he ever notice that the Argument from Incredulity is not considered sound scientific practice (see, for example, its other conclusions: geocentrism, Intelligent Design creationism, opposition to plate teconics)? Apparently not—Witt must think that his own work brushes all past experience under the rug. This is, sadly, the familiar crackpot standard.

Oddly enough, I can think of at least one self-proclaimed revolutionary (also a tireless self-promoter) who hadn’t even made it through that middle-school lesson about “probability clouds.”

It’s hard to pick a favorite absurdity amongst all the ones which Witt manages to deliver. I rather liked how his “Null Physics” forbids hydrogen atoms from emitting light in the infrared, optical and ultraviolet spectra. On the other hand, declaring that energy has the units of time × distance² is also pretty classy; it’s reminiscent of the Autodynamics guy claiming that . And the chain of successive arbitrary handwaves in which he indulges to “explain” the cosmic microwave background is a downright tour de force of fractured-ceramic thinking.

In summary, “Null Physics” has, aptly, a content value of exactly null.

Maybe a “quantum xrroid” means that your X is in a superposition of inflamed and not inflamed and only settles on one or the other option when your doctor examines it.

(Incidentally, I met the redoubtable Ben Goldacre in Vegas a few weeks ago — and thereby would hang a tale, if he weren’t still hoarding the photo evidence.)

(If you’re looking for the lyrics to “I Google You,” they’re a couple posts in the past.)

Robert H. Brandenberger, “String Gas Cosmology” (arXiv:0808.0746).

String gas cosmology is a string theory-based approach to early universe cosmology which is based on making use of robust features of string theory such as the existence of new states and new symmetries. A first goal of string gas cosmology is to understand how string theory can effect the earliest moments of cosmology before the effective field theory approach which underlies standard and inflationary cosmology becomes valid. String gas cosmology may also provide an alternative to the current standard paradigm of cosmology, the inflationary universe scenario. Here, the current status of string gas cosmology is reviewed.

Dimitri Skliros, Mark Hindmarsh, “Large Radius Hagedorn Regime in String Gas Cosmology” (arXiv:0712.1254, to be published in Phys. Rev. D).

We calculate the equation of state of a gas of strings at high density in a large toroidal universe, and use it to determine the cosmological evolution of background metric and dilaton fields in the entire large radius Hagedorn regime, (ln S)^{1/d} << R << S^{1/d} (with S the total entropy). The pressure in this regime is not vanishing but of O(1), while the equation of state is proportional to volume, which makes our solutions significantly different from previously published approximate solutions. For example, we are able to calculate the duration of the high-density "Hagedorn" phase, which increases exponentially with increasing entropy, S. We go on to discuss the difficulties of the scenario, quantifying the problems of establishing thermal equilibrium and producing a large but not too weakly-coupled universe.

V. M. Kenkre, Niraj Kumar, “Nonlinearity in Bacterial Population Dynamics: Proposal for Experiments for the Observation of Abrupt Transitions in Patches” (arXiv:0808.0172).

An explicit proposal for experiments leading to abrupt transitions in spatially extended bacterial populations in a Petri dish is presented on the basis of an exact formula obtained through an analytic theory. The theory provides accurately the transition expressions in spite of the fact that the actual solutions, which involve strong nonlinearity, are inaccessible to it. The analytic expressions are verified through numerical solutions of the relevant nonlinear equation. The experimental set-up suggested uses opaque masks in a Petri dish bathed in ultraviolet radiation as in Lin et al., Biophys. J. {\bf 87}, 75 (2004) and Perry, J. R. Soc. Interface {\bf 2}, 379 (2005) but is based on the interplay of two distances the bacteria must traverse, one of them favorable and the other adverse. As a result of this interplay feature, the experiments proposed introduce highly enhanced reliability in interpretation of observations and in the potential for extraction of system parameters.

Authors: M. S. Baptista, F. Moukam Kakmeni, Gianluigi Del Magno, M. S. Hussein, “Bounds for Kolmogorov-Sinai entropy of active networks” (arXiv:0805.3487).

According to the Pesin entropy formula [Y. B. Pesin, Russia Mathematical Survey vol. 32, 55 (1977)], the sum of all the positive Lyapunov exponents of a dynamical system (with smooth invariant measure) provides the Kolmogorov-Sinai (KS) entropy. Such result allows one to calculate this entropy even for very complex chaotic networks, by only using the Lyapunov exponents. However, when the size of the network becomes large, even the Pesin formula becomes unpractical, as the Lyapunov exponents demand heavy numerical computations. Here, we show that for a large class of dynamical systems, the sum of all the positive Lyapunov exponents of an active network (formed by nodes that are not necessarely synchronous) is bounded by the sum of all the positive Lyapunov exponents of the synchronization manifold, a quantity that can be straightforwardly calculated by only knowing the connecting matrix of the network and the low-dimensional dynamics of the synchronization manifold. This fact enables one to predict the behavior of a large network by using information provided by only two coupled nodes.

Damn. I remember when Googling your date was something only MIT students did. Tempus frangit. (I leave to you, Gentle Reader, the obvious punch line about the likelihood of MIT students finding dates in the first place.) Incidentally, does anyone else feel rewarded when they recognize that two successive Neil Gaiman blog-post titles are, ultimately, riffs on Milton’s Samson Agonistes (1671)?

UPDATE: The lyricist provides the words in the comments below.

(When the next attempt to lay a cable worked, Thomson became Lord Kelvin, and his name lives on in the Kelvin scale, which measures temperatures in units the size of Celsius degrees but starting at absolute zero.)

“List to the new words to a common song,” Maxwell wrote to a friend, “which I conceived on the railway to Glasgow. As I have only a bizzing, loose, interruption-to-talking- &-deathblow-to-general-conversation-memory of the orthodox version, I don’t know if the metre is correct; but it is some such rambling metre anyhow, and contains some insignificant though apparently treasonable remarks in a perfect thicket of vain repetitions.” For the sake of efficiency, Maxwell introduced the notation “2(u)” for the refrain, “Under the sea, under the sea.”

THE SONG OF THE ATLANTIC TELEGRAPH COMPANY

I.
2(u)
Mark how the telegraph motions to me,
2(u)
Signals are coming along,
With a wag, wag, wag;
The telegraph needle is vibrating free,
And every vibration is telling to me
How they drag, drag, drag,
The telegraph cable along,

II.
2(u)
No little signals are coming to me
2(u)
Something has surely gone wrong,
And it’s broke, broke, broke;
What is the cause of it does not transpire,
But something has broken the telegraph wire
With a stroke, stroke, stroke,
Or else they’ve been pulling too strong.

III.
2(u)
Fishes are whispering. What can it be,
2(u)
So many hundred miles long?
For it’s strange, strange, strange,
How they could spin out such durable stuff,
Lying all wiry, elastic, and tough,
Without change, change, change,
In the salt water so strong.

IV.
2(u)
There let us leave it for fishes to see;
2(u)
They’ll see lots of cables ere long,
For we’ll twine, twine, twine,
And spin a new cable, and try it again,
And settle our bargains of cotton and grain,
With a line, line, line,—
A line that will never go wrong.

That’s all for now. I bought a Greg Egan book, stayed up all hours to finish it and now I think I’m on Australia time.

It began with some fluff about early models of the atom, leaving out most of the ideas actually proposed in favor of a “textbook cardboard” version of the discoveries made in early TwenCen. If we can’t teach history well, why teach it at all? We’re certainly not promoting a genuine understanding of how science works if we only present a caricature of it. I doubt one could even instil an appreciation for the problems which Bohr, Heisenberg, Schrödinger and company solved in the years leading up to 1927: sophomore physics students can’t follow in their footsteps, because sophomore physics students don’t know as much classical physics as professional physicists of the 1920s did. To understand their starting point and the steps they took requires, oddly enough, subject material which even MIT undergrads don’t learn until later.

After the textbook-cardboard version of history, we proceeded to solve the Schrödinger Equation in a great many different circumstances. This was supposed to “build intuition about quantum mechanics,” but I think all it built in most people was a loathing of differential equations. The course was capped off with a cursory treatment of the Bell Inequality.

Looking back, the only thing I learned in 8.04 which I didn’t see derived again, more cleanly and more memorably, in a later course was how a delta-function potential acts in the Schrödinger Equation — and that takes, what, half the back of an envelope to work out? (OK, given small handwriting.)

I have occasionally wondered whether it would be possible to build a first-term quantum physics course out of Feynman’s QED: The Strange Theory of Light and Matter (1985). If you’re teaching to university students, they probably already have experience with complex numbers, trigonometry and some amount of calculus, so you’ll be able to write actual exercises based on the book’s conceptual material.

Either before or after the chapter on the Standard Model’s particle content, expand the book with two-state systems, the Bell Inequality and entanglement stuff. (I might do it after the Standard Model chapter, so I could lead into it with a little kaon physics.) After entanglement, introduce decoherence. Follow with the model of electrons hopping from atom to atom expounded in the Lectures on Physics, chapter III-13, and use it to motivate band-gap behavior and, by shrinking the lattice spacing, the Schrödinger Equation (chapter III-16). Solve the particle-in-a-box and the harmonic oscillator, and then bid the kids a happy summer vacation.

I don’t pretend to know how well this programme would work, and I’ve certainly never tried it on a live audience, but I do think the way I was introduced to QM was wasted effort which fails in its stated aim of “building intuition.” The time is nigh for reform — come, let us tear down the old edifice of incomprehensible authority and build a better one anew! (Singing “Dem Bones” is optional.)

This is quintessential science history: tangled up, twisted around and downright weird. Naturally, I love it.

Shamit Kachru (Stanford University) has an article on this issue in the American Physical Society’s new online publication, called simply Physics, a journal intended to track trends and illustrate highlights of interdisciplinary research. Kachru’s essay, “Glimmers of a connection between string theory and atomic physics,” does not focus on the nuclear physics applications currently being investigated, but rather explores a more recent line of inquiry: the application of string theory to phase transitions in big aggregates of atoms. Screwing around with lithium atoms in a magnetic trap is, by most standards, considerably more convenient than building a giant particle accelerator, so if you can get your math to cough up predictions, you can test them with a tabletop experiment.

(Well, maybe you’ll need a large table.)

If you’ve grown used to hearing string theory advertised as a way to solve quantum gravity, this might sound like cheating. Justification-by-spinoff is always a risky approach. It’s as if NASA said, “We’re still stalled on that going-to-the-Moon business, but — hey — here’s TANG!” But, if your spinoff involves something like understanding high-temperature superconductivity, one might argue that a better analogy would be trying for the Moon and getting weather satellites and GPS along the way.

Moreover, one should not forget that without Tang, we could not have invented the Buzzed Aldrin.