Wednesday, August 21, 2013

Sins of philosophers

In July 22, 2013 New Yorker, James Wood writes:

Almost twenty years ago, George Steiner suggested in these pages that doing philosophy was incompatible with domestic life. Speaking of the troubled French thinker Louis Althusser, Steiner proposed that sometimes it might be necessary for a philosopher to strangle his wife. (As, alas, Althusser did.) There is something vulgar and absurd, he continued, in the notion of a Mrs. Plato, a Madame Descartes. You cannot commit to taking out the garbage or doing the dishes while also solving the problem of the cogito or announcing the death of God. Being George Steiner, he charged his argument with bolts of existential electricity. In his reading, Zarathustra is at best a rough, undomesticated beast and at worst a murderous lunatic. Up on Olympus you feel free, not in the kitchen or the faculty lounge.
I have always liked Tolstoy’s diary entry from 1863: “Family happiness completely absorbs me, and it’s impossible to do anything.” Tolstoy is indeed the great novelist of family happiness, but delight is tempered by the vision of the father and husband he became—selfish, tyrannical, more faithful to his literary and religious followers than to his biological successors. Even gentle Chekhov joked that he would prefer a wife “who, like the moon, won’t appear in my sky every day.” He contrived to marry late in his short life, and spent much of his marriage in Yalta, while Olga Knipper worked a thousand miles away, in Moscow....

Monday, August 19, 2013

Dreams of theorists

S writes: "Last night I dreamt of traffic cops that would stop and fine chaotic drivers. I saw them stopping someone and I intervened - how did they establish that the driver was chaotic? Had they computed Lyapunov exponents? Did they know whether it was real chaos or non-normal chaos?"

Tuesday, August 13, 2013

This time, they say, Einstein might really be wrong

Today's  Dennis Overbye is priceless:
.... this violated a basic tenet of modern science and of quantum theory, that information is always preserved...
I'm sitting here with two other scientists, here we are, ages 90, 82 and 67, spent our whole lives as card carrying physicists, and until this minute, we had no idea that this is the basic tenet. See, we never got the memo.
... in a sense physicists had already thrown Einstein under the bus. In Dr. Maldacena’s holographic universe, considered to be the last word on quantum gravity, the dimensions of space-time do not seem to matter. “We’ve known for years that space-time is not fundamental,” Dr. Polchinski said. “General relativity is not fundamental.” He went on, “space-time is emergent. Gravity is emergent. Maybe sometimes it doesn’t always emerge.”...
And guess what - not only there is no experiment, there cannot be an experiment:
... Daniel Harlow of Princeton and Patrick Hayden of McGill University suggested that the issue might be moot; the computation necessary to verify that Alice and Bob are entangled could take longer than the age of the universe and the black hole would evaporate in the meantime, making it impossible ever to go inside and experience the contradiction...
Brilliant, no?

There are already more than 300 comments, one more helpful than the other:
Bondosan: I am reminded of the Buddhist concept of the Four Sufferings: Birth, Aging, Sickness, and Death, which apply not only to individuals but to entire world systems as well...
The modern thing is to make virtue of predictions being untestable. Here are news from CERN:
The LHCb and CMS experiments at CERN have announced the first definitive observation B0s→μ μ− decay. This is one of the rarest processes in fundamental physics, predicted by the Standard Model to occur only about 3 times in every billion. Where the result is a remarkable success for the Standard Model, around the web it has also been called a serious blow to supersymmetric symmetry (SUSY) models.

But  Gordon Kane points out that some supersymmetric theories actually predict that some superpartners lead to experimental results very close to the Standard Model ones, particularly those that affect these newly observed rare decays. He and his colleagues made quantitative predictions of Bs meson decay to muons based on the compactification of M-theory that deviate from the Standard Model prediction by a percent or so. Jim Gates also bemoans talk of the death of SUSY. "SUSY has a huge parameter space and it will take years, if not decades, to experimentally explore it all. So declaring SUSY dead is most certainly premature."

While I'm on the roll with matters delirious:
Is it possible that time is real, and that the laws of physics are not fixed? Lee Smolin, A C Grayling, Gillian Tett, and Bronwen Maddox explore the implications of such a profound re-think of the natural and social sciences, and consider how it might impact the way we think about surviving the future.
Einstein is invoked only in min. 4. Gotta hand it to Lee for professorial grooming, though.

Monday, August 12, 2013

Lyapunov exponents - good for what?

David M writes:

Q: I am working in nonlinear dynamics in the area of Sports Science and was intrigued by your comments in (version14.4.1), Chapter 6 Lyapunov exponents:
In short: Lyapunov exponents are an abomination. We are doubtful of their utility as means of predicting any observables of physical significance, but that is the minority position - in the literature one encounters many provocative speculations, especially in the context of foundations of statistical mechanics (`hydrodynamic' modes) and the existence of a Lyapunov spectrum in the thermodynamic limit of spatiotemporal chaotic systems.
Lyapunov exponents are used extensively in the literature of nonlinear systems as an indicator of chaos.  Do you have any suggestions as what should be used as an indicator in place of Lyapunov exponents - is it a number of multiple factors that indicate Chaos?

A: thanks for pointing this out, I thought I had censored the 'abomination' already - it was stated so emphatically because I cannot get my students deprogrammed from 'Lyapunov exponents' no matter how I rewrite the stability chapters, but it gets colleagues' hair up. How about this revision:

In short: we do not recommend that you evaluate Lyapunov exponents; compute stability exponents and the associated covariant vectors instead. Cost less and gets you more insight. Whatever you call your exponents, please state clearly how are they being computed. While the Lyapunov exponents are a diagnostic for chaos, we are doubtful of their utility as  means of predicting any observables of physical significance. This is the minority position - in the literature one encounters many provocative speculations, especially in the context of foundations of statistical mechanics (`hydrodynamic' modes) and the existence of a Lyapunov spectrum in the thermodynamic limit of spatiotemporal chaotic systems.

'Stability exponents' and the associated 'covariant vectors' are defined in the preceding "Local stability" and "Cycle stability" chapters. The "Lyapunov exponents" chapter I had to write because it is only very recently that people (see  Ginelli et al. Covariant Lyapunov vectors, J. Phys. A 46, 254005 (2013), do the right thing.

Wednesday, August 07, 2013

Theresa is no Catherine: I got my Catholic saints mixed up :)

[this post has lots of clickable links; "mudders" hick hop link is highly recommended]

I love 'Lives of Saints', as much as I hate annual reports, and here is what I learned while avoiding to work on the recent deadline:
Bernini's ecstasy depicts not Catherine, but the other woman saint. 

The original Catherine (the Lady of The Wheel) was not so lucky to be sainted for an orgasm, but sure was a major pain: "Consternated by her learned denunciation of paganism, Maxentius summoned fifty philosophers to trounce her in a public debate, but Katherine instead converted them all to Christianity.".

Feast Day: November 25th;
Date of Death: A.D. 307; Cause of Death: broken on the wheel and then, just to make sure, beheaded. (Santa Cecilia sung for three days after beheading. She however, did not merit a Bernini - though you might like the modern version better).

She was a chick saint, transported to heaven to marry Jesus in a mystical wedding ceremony:"Attuned to the interests of women, who were avid readers and patrons in 1440s East Anglia, Capgrave develops those aspects of the virgin martyr's relationship with her heavenly spouse that provincial wives could understand: her longing for her absent husband, for example". You Catherine are the patron of philosophers, theologians and royal women. Were you less fortunate, you could have been the patron saint of mudders.

There are two kinds of saints: either martyrs, quartered and sliced in imaginative ways, or the agile fund raisers. You got the both genes in you:)

The fund raiser was pretty scary too, caused lots of trouble in her 33 terrestrial years: "Catherine threw herself into Pope Gregory's campaign for another crusade to wrest the Holy Sepulchre from the Turks". And so our troubles started.

The runaway St. Flora likewise had issues with Muslims and, on the helpful advice of St. Eulogius, was decapitated only after a tour in brothel.  She wavered and trembled on her way to glory. She is patroness of the abandoned, converts, single laywomen and victims of betrayal. Feast day: October 5.

Then there is St. Flora of Beaulieu who did nothing of note, other than being mobbed by the sisters: "Like many saints, Saint Fleur was subject to the suspicions of her mother superior who could not admit or imagine the eminent virtue of her inferior". But she was a good girl and so went to heaven. Somehow she too, through the infinite wisdom of internet (conflated here), became patroness of the abandoned, converts, single laywomen and victims of betrayal. Feast day: November 24.