Friday, October 29, 2010

This and That

With the weekend approaching, here's some distractions to kill your remaining working hours till 5pm:
  • A very nice applet that zooms you through the scales of the universe, all the way down to the Planck length.

  • An interesting recollection by Robert Weisbrot of Edward Witten's way to physics:

    "I am reminded of a friend from the early 1970s, Edward Witten. I liked Ed, but felt sorry for him, too, because, for all his potential, he lacked focus. He had been a history major in college, and a linguistics minor. On graduating, though, he concluded that, as rewarding as these fields had been, he was not really cut out to make a living at them. He decided that what he was really meant to do was study economics. And so, he applied to graduate school, and was accepted at the University of Wisconsin. And, after only a semester, he dropped out of the program. Not for him. So, history was out; linguistics, out; economics, out. What to do? This was a time of widespread political activism, and Ed became an aide to Senator George McGovern, then running for the presidency on an anti-war platform. He also wrote articles for political journals like the Nation and the New Republic. After some months, Ed realized that politics was not for him, because, in his words, it demanded qualities he did not have, foremost among them common sense. All right, then: history, linguistics, economics, politics, were all out as career choices. What to do? Ed suddenly realized that he was really suited to study mathematics. So he applied to graduate school, and was accepted at Princeton. I met him midway through his first year there--just after he had dropped out of the mathematics department. He realized, he said, that what he was really meant to do was study physics; he applied to the physics department, and was accepted.

    I was happy for him. But I lamented all the false starts he had made, and how his career opportunities appeared to be passing him by. Many years later, in 1987, I was reading the New York Times magazine and saw a full-page picture akin to a mug shot, of a thin man with a large head staring out of thick glasses. It was Ed Witten! I was stunned. What was he doing in the Times magazine? Well, he was being profiled as the Einstein of his age, a pioneer of a revolution in physics called "String Theory." Colleagues at Harvard and Princeton, who marvelled at his use of bizarre mathematics to solve physics problems, claimed that his ideas, popularly called a "theory of everything," might at last explain the origins and nature of the cosmos. Ed said modestly of his theories that it was really much easier to solve problems when you analyzed them in at least ten dimensions. Perhaps. Much clearer to me was an observation Ed made that appeared near the end of this article: every one of us has talent; the great challenge in life is finding an outlet to express it. I thought, he has truly earned the right to say that. And I realized that, for all my earlier concerns that he had squandered his time, in fact his entire career path--the ventures in history, linguistics, economics, politics, math, as well as physics--had been rewarding: a time of hard work, self-discovery, and new insight into his potential based on growing experience."


    [Via Michael Nielsen, via Hacker News. Read the full speech here.]

  • You might already have read it on Nature News: Astronomers have found the to date most massive neutron star with about 2 solar masses. When I read this, a bell was ringing faintly in the dusty back of my head. Meanwhile I've figured out what was ringing: Smolin's Cosmological Natural Selection predicts an upper mass limit for neutron stars of 1.6 solar masses. (See hep-th/0612185, section 3.2).

  • Some months ago I was sent a link to an April fools day paper, funny-haha, physicists style. That paper has now resurfaced on my desk: Schrödinger's Cat is not Alone. It's a humorous take on the interpretation of quantum mechanics and cat dynamics. Not the sort of humor that deepens my laugh wrinkles, but I thought some of you might find it amusing.

  • Here's something that did give me a good laugh. Real life absurdity:
    Nurses find the weirdest stuff. [Via Bora].

I wish you all a nice weekend!

20 comments:

Steven Colyer said...

Hi Bee, Do you LIKE Lee Smolin's Cosmological Natural Selection?

I do, with zero proof that it's right, and I wrack my brain daily thinking about an experiment that would prove it one way or the other.

Sean Carroll disagrees that a Universe can exist inside a black hole, which reminds me, yet again, how much physicists disagree with each other at the cutting edge that is speculative physics.

But that's Cosmology, which I comfort myself thinking of as speculative Astronomy. Astronomers have, or at least had, an intense history of being petty and vindictive with each other (Hubble had a mean spirit), indeed first so amongst the Sciences that way. Not sure that's true anymore, but if so, was Fred Hoyle the reason?

Bee said...

Well... I like the idea, baby universes and so on, cute ;-) (Also, cute puppy in your profile pic. Yours?) I'm not too convinced by the realization though. Mostly because I think the "number of black holes" is ill-defined. In any case, I've been wondering why the idea didn't catch more fire. After all, it's how old now? 15 years? 20? It seems to me possible there might be more plausible variations of CNS, same basic idea, different realization. If I recall correctly, there's 2 or 3 papers on that, but that's about it. Keep thinking Lee's been ahead of his time. Chances are, this idea will come back in a decade or two in some slightly modified version.

I thought Carroll is also into baby universes, no? He probably has an issue with the question of entropy though, it's his theme, isn't it? Best,

B.

Uncle Al said...

http://www.mazepath.com/uncleal/uncleal2.jpg
Uncle Al likes cats. That was Xerxes.

Mathematics has no empirical basis, by definition. Thus string theory, economics, SUSY, meteorology... Hey Ed, it's not a soufflé until it's served persistently inflated to resist a fork.

Nature 467, 1081 (2010)
Who wanted them to look?
Phys. Rep. 442, 109-165 (2007)
Modeled neutron stars

1.74 solar-mass 465.14 Hz pulsar PSR J1903+0327 and its 1.05 solar-mass companion were hot stuff. The pulsar's core was publishable: hyperons, delta isobars, deconfined quark matter, Bose condensate, meson condensate (pion, kaon)...

1.97 solar mass 317 Hz pulsar J1614-2230 is a binary with a white dwarf. Neutron star cores are neutrons. Everything else is insufficiently rigid to prevent black hole collapse... until "parameters are adjusted." Horsefeathers (with Πήγασος as model).

Take care when dating a nurse, especially just before she giggles. Precognition can be of value here.

Steven Colyer said...

Hi Bee,

You wrote:
I've been wondering why the idea didn't catch more fire.

Me neither, but you must admit Fecund universe theory is somewhat shocking the first time you hear of it. When I first read of it was adamantly against it, for example (what are you physicists smoking?!), so my first response was to disprove it.

Funny thing, I couldn't disprove it logically and I still can't. Can't prove it, either. So it goes on my ever-growing pile of "Intriguing" Theories, like SuperStrings. Might be right. Might not be right. Who knows?

Politically speaking, Lee has established himself as co-kight with Peter Woit in The String Theory Wars, and that may have clouded out the attention it possibly deserves. Shrug, dunno, just a thought.

Regarding Carroll, I wrote a piece
here (which is probably very, very wrong) about HOW in the most abstract terms a universe MIGHT exist inside a black hole, and within a week Carroll wrote this at Cosmic varience, which I'm sure is pure co-incidence. (Lubos had a response to Sean's thread, which I will not link to here for reasons previously discussed).

No, that's not a picture of my walnut-size brained Dachshund, Pippin (so named because dachshunds are hobbits amongst dogs), but I love that breed the most. And to think, in typical Teutonic efficiency, the Germans bred these "badger hounds" 2-300 years ago for the most practical of reasons, to go into the badger nests that plagued German farmers of the time, as hound dogs with normal sized legs couldn't. What, you didn't have beagles handy? Well done, I love my Pippy, he's like the baby that never grows up. Thank you, Germany.

"That's "Lump", my dachshund. He's not a human, but he's not a dog either. He's something else."
... Pablo Picasso

Robert L. Oldershaw said...

Regarding the observation of a neutron star with a mass of about 2 solar masses, consider the following.

My research leads me to the concluson that the upper limit mass for a "stellar-mass" black hole or neutron star (the former in a highly excited state) is about 30 solar masses.

The most massive observed "stellar-mass" black hole has an estimated mass on the order of 23-34 solar masses.

So I expect that the upper limit for neutron star masses will climb steadily far beyond what is "possible" according to current theoretical assumptions.

These are definitive predictions and they have been published in peer-reviewed journals.

Best,
RLO

Steven Colyer said...
This comment has been removed by the author.
Steven Colyer said...

Regarding the Scale of the Universe thing by Cary and Michael Huang, yup, that's pretty amazing and thank you for that, Bee and Stefan, but of course I have some comments on it:

1) Preons? Preons?! Are those accepted now by mainstream Physics, or are they a mere speculative fantasy from the mind of John Archibald Wheeler? I'd thought it was the latter, hmm.

2) Where are the Hellameters?

3) Nice to see Half-Dome from Yosemite National Park, a 3-hr drive east of San Francisco in the Sierra mountains, represented. I've been there, and can die happy now, as I can't imagine a place more beautiful. Well, I've never been to Hawaii's Kauai garden island, but I have seen Jurassic Park, and that'll have to do in this life. Still, seeing a mountain on screen or in a photograph can't compare with being there. And speaking of mountains ...

3) The LHC is slightly wider than Mt. Everest is tall? Cool. Here's hoping the French power grid can keep up, wow. Both are dwarfed by a 26-mile marathon.

Now, if only we can get a similar thing re Time, that would be great.

Phil Warnell said...

Hi Bee,

Thanks, as I find this tale regarding Witten being interesting, as I also draw the same conclusion regarding the nature and character of him as that of the author. However, what I think perhaps being the more important thing, which is easily missed as it only to be found buried between the lines, being for me it serves to have made more clear how people differ, as to what they consider to be the purpose in having a career.

That is I would suggest for many, if not most, a career is more thought of as a means of getting one through life, while for those like Witten it rather serves as to give some meaning to one’s life. In fact I strongly identify with Witten in many respects, which is not to suggest I share in his extraordinary depth of aptitude, drive, persistence and natural ability, yet rather like him have always been more interested in what I could come to understand respectful of what it is that gives meaning to ones existence.

The place that we differ however, is him succeeding in having what sustains him in substance, being the same which sustains him in purpose; with this being something I’m left simply as able to imagine what a joy that could be. I would also have it be clear, this not meant as to complain, yet only to tip my hat to one of those few who having what it takes to be able to make it so, and perhaps to stop and wonder, if for only just a moment, as to what that would be like.

Best,

Phil

Robert L. Oldershaw said...

For decades there has been virtual hero-worship of Witten within the theoretical physics community.

There is no question about the fact that he is exceptionally knowledgeable and creative in analytical matters, especially the intersection of math and physics.

However, I think one could argue that when it comes to a conceptual understanding of nature, he talents are, at best, average.

I also think that for those same decades we have assumed that those with exceptional analytical talent by definition also have exceptional conceptual talent.

My guess is that when people look back on this era in theoretical physics, this failure to distinguish between analytical and conceptual understanding will be regarded as a, if not the, major contributory flaw.

Phil Warnell said...
This comment has been removed by the author.
Phil Warnell said...

Hi Robert,

First I would hope what I had to say about Witten as not being taken as hero worship or zealot like admiration, beyond in him being one persistent enough in the pursuit to find what stands to be his purpose. That said, I would admit how Witten does serve to inspire me being resultantly that he demonstrates the potential which our species as a whole might one day rejoice in having made true for many if not all. That’s not to say that I think everyone today could become a Witten, rather this has me convinced that one day more like him will stand as what being the ordinary rather than the extraordinary. Some might say this not being possible and a foolish thought, as it being like to image the IQ bell curve as able to change its shape. However this is not what I find as to be possible, rather suggest there being no reason not to imagine rather than change its shape, merely it drift to the right and thus be fully consistent with nature, respective of its potentials and limits.

However I would agree that in general Witten’s importance and contributions are overplayed more than a bit, as him not being the either the originator of the string concept or one of its initial developers; yet rather the one who demonstrated that its many approaches being related as different facets of a theory that still eludes both himself and his disciples. Somehow I think this by many is considered to be the same as when it was demonstrated that both Heisenberg’s and Schrodinger’s approaches to QM as being equivalent. That is in respect to QM it did actually serve to strengthen its validity. However, with strings Witten didn’t demonstrate the same type of equivalence, yet rather what equivalence there being only to be found in an encompassing theory respective to them all and thus not holding the same significance as when one has two different approaches end in the same conclusion. This type of related confirmation can also be found between the different roads to SR was Bell was so aptly point out.

However ,this overemphasis of the importance of one scientist and/or his approach over another’s is nothing new, as for instance the same being true in respect to the considered value of Descartes being demoted as to thought as being nothing when compared with the revelations of Newton. This I’ve always found to have been best expressed by Voltaire when speaking in England upon the occasion of Newton’s death in saying the following

“We may admire Sir Isaac Newton on this occasion, but then we must not censure Descartes. The opinion that generally prevails in England with regard to these new philosophers is, that the latter was a dreamer, and the former a sage.”

“Very few people in England read Descartes, whose works indeed are now useless. On the other side, but a small number peruse those of Sir Isaac, because to do this the student must be deeply skilled in the mathematics, otherwise those works will be unintelligible to him. But notwithstanding this, these great men are the subject of everyone's discourse. Sir Isaac Newton is allowed every advantage, whilst Descartes is not indulged a single one. According to some, it is to the former that we owe the discovery of a vacuum, that the air is a heavy body, and the invention of telescopes. In a word, Sir Isaac Newton is here as the Hercules of fabulous story, to whom the ignorant ascribed all the feats of ancient heroes. “

-François-Marie Aroue (aka Voltaire)- 1727


Best,

Phil

Bee said...

Hi Steven,

I see. That's a different point though. You can't make a universe out of a black hole in ordinary general relativity. There has to be some transition (quantum gravitational?!) that does not obey the standard laws and that subsequently leaves you with a new "baby" universe. Not knowing how that transition actually works, looking back in time doesn't help you figure out where you came from however. If I recall correctly, Lee just assumed that this works somehow. And in addition there has to be some mechanism to scramble the "genes" (constants of nature) of the mommy-universe during this transition, otherwise there's no mutation, and no natural selection. Best,

B.

Bee said...

Hi Phil,

Yes, it's an interesting story. The persistence of his trying to find the place to fit in is quite remarkable. While one certainly shouldn't generalize one person's story, it is also interesting to note which fields he did not feel his intellect would be well used. Especially when it comes to politics it seems to me the most intelligent people shy away from it because it's burdened with such a bulk of seriously dumb games. Who'd want to waste their brain on all this crap? Unfortunately, the result is that politics tends to be dominated by people who have a liking in these games rather than those who actually have the insight. Best,

B.

Phil Warnell said...
This comment has been removed by the author.
Phil Warnell said...

Hi Bee,

Unfortunately, the result is that politics tends to be dominated by people who have a liking in these games rather than those who actually have the insight.

I think you’re being too kind to politicians, particularly as of late it appears the most successful being those that tell the people what they want to hear, rather than what they need to hear, and if that doesn’t work play upon their most primal of fears to have done what they want. We are probably lucky that we are not ruled by the most intelligent as these lies, deceptions and tactics could be even harder to have made transparent.

No I think it better it be respected by the intellectuals their best place is in being only able to lend guidance to both the leaders and governed as what be the best options and methods, rather than having them to be the ones to decide, as in the end there is no reason to suspect them to being any less vulnerable to the temptations and thus the abuses that having power can bring. That’s to say being a tyrant has nothing to do with how bright one is, only as to how effective of a one they might be.

"Democracy is a device that ensures we shall be governed no better than we deserve.”

-George Bernard Shaw

The above quote is for me to suggest, that first all should participate in the process, as having us able to find consensus respectful of what it is that we deserve; whereas the place for the natural philosophers, is to have envisioned, for the purpose of making real, what being possible to be deserving of and yet left primarily to other philosophers to have it become understood to us all, what it is to be deserving.

Best,

Phil

Steven Colyer said...

The best way to succeed in (American) politics is be be born to a Yale University Skull & Bones society member, be one yourself, or be willing to deal with them. I never will, because they stole Geronimo's skull, which greatly offends me. Free Leonard Peltier!

Robert L. Oldershaw said...

Phil et al,

When you study Einstein's work carefully, whether it's the photon theory of radiation, stimulated emission, general relativity, etc., you see that it is his gifts in conceptual thinking that led him to his discoveries, which were subsequently given mathematical expression.

This is especially clear with general relativity. Almost completely isolated intellectually in this quest, with virtually no one supporting his vision, he questioned why inertial motion should be special. In a purely conceptual mode of thinking he explored the relativity of all motion, had the conceptual breakthrough of there being no gravitational field in free fall, and began to see the conceptual outline of the interplay between S-T geometry and matter.

Only then did he go to his mathematical friend Grossmann and ask him if there was a mathematical framework that could express these conceptual ideas in a fully analytical format.

My story is greatly simplified, but it identifies the key source of Einstein's genius: conceptual thinking.

This is what has been missing for many decades.

RLO

Steven Colyer said...

Very nicely put, Robert, to which I would add that as he aged, and possibly because of Grossman's influence, he got deeper into the Mathematics and farther from the concepts. That he produced less (the EPR paper being an exception) in his later years may or may not have been due to that shift, but there may be a cautionary tale there, nevertheless.

As to your comment "almost completely isolated intellectually in this quest, with virtually no one supporting his vision", I'm glad you added "almost", because the great German mathematician David Hilbert was totally on board with Gen Rev, going so far as to publishing his version 4 days before Einstein's last of 4 lectures on the same at The Prussian Academy.

Indeed, it was the gentlemanly competition with Hilbert, along with the fact that Einstein was between wives such that he had time on his hands to devote to his obsession, that gave impetus to solving said field equations, at the tender age of 36.

Steven Colyer said...

Getting back to the Scales of the Universe thing ...

According to the app, a yoctometer is 10^-24 m equals the alleged diameter of a neutrino (non high-energy state), which is the smallest thing that's not highly speculative, "speculative" being those things ELEVEN ORDERS of magnitude down from a yoctometer at the tight 10^-35 m scale.

Geez louise, I thought they were considered point particles in QFT. Who figured neutrino diameters out and how? When did this happen?

Bee said...

It may comfort you to hear that I've never heard of the neutrino having a diameter either. The only thing I can think of is somebody taking the square root of the typical cross-section. These are actually energy-dependent, but for the average energies of, say, solar neutrinos, it might just fit:

http://cupp.oulu.fi/neutrino/nd-cross.html