The Quantum Pontiff

Various and Sundry

Two notes from Caltech of interest:

  • Michael L. Roukes’ group at Caltech has produced a NEMS (nanoelectromechanical system) device which can (almost) measure the mass of a single molecule (as opposed to the many tens of thousands (is this the correct amount?) needed in mass spectrometry.) Build a 2 micrometer by 100 nanometer NEMS resonator. Drop a molecule on it. The frequency of vibration of the NEMS resonator changes. Detect this frequency change. Of course vibration frequency also depends on where the molecule lands. So run the experiment about 500 times to get good estimate of the mass. Future (all ready prototyped) work should alleviate the problem of where the molecule lands causing a need for repeated experiments. From the press release:
    Eventually, Roukes and colleagues hope to create arrays of perhaps hundreds of thousands of the NEMS mass spectrometers, working in parallel, which could determine the masses of hundreds of thousands of molecules “in an instant,” Naik says.

    As Roukes points out, “the next generation of instrumentation for the life sciences-especially those for systems biology, which allows us to reverse-engineer biological systems-must enable proteomic analysis with very high throughput. The potential power of our approach is that it is based on semiconductor microelectronics fabrication, which has allowed creation of perhaps mankind’s most complex technology.”

  • Hawaii beats Chile as site of new Thirty meter telescope.

For the past few months I’ve been getting back into shape by running my rear end off. On these jaunts, when I’m not in the mood for KEXP (they stream check them out!) I try to fill my head with something that isn’t mind numbingly dumb (read most radio stations.) Good podcasts include EconTalk where you get to hear about the dismal science. The interviewer, Russ Roberts, has a very strong libertarian (Austrian school) bent, but even when he disagrees he does ask the questions. I think we get to call it the dismal science because a recent interview was on “The Rational Market.” Apparently economists believe that the economy can pass the Turing test! Anyone else have good recommendations for non brain dead podcasts?

Speaking of finance, the Information Processor has two posts up that are worth looking at: Against Finance and Goldman apologia. The lesson of this financial crisis (and LTCM and…) is that when Goldman comes knocking at your door with a deal, run, don’t walk screaming for the door!

Nate Silver has gotten sick of climate skepticism and the daily weather report, and so lays down some money for those who want to bet against average weather statistics. Time to see if I can find a hometown where the weather instruments have been recently changed.

Comments

  1. #1 Sundar Srinivasan
    July 23, 2009

    Just curious. How do they measure the change in standing wave frequency in that a nanometric resonator? Do they have a nanometric measuring device?

  2. #2 Phil H
    July 23, 2009

    Recommendations for ‘non brain dead podcasts’:

    http://plus.maths.org/podcasts/ – mathematics, expository

    http://www.cbc.ca/spark/ – CBC radio on technology, culture

    http://www.abc.net.au/rn/subjects/ – ABC radio programs on topics from arts to war

    and if you can’t find anything of interest in the above, you can always try http://www.podcastdirectory.com/

  3. #3 Neil B ♪
    July 23, 2009

    A thirty-meter telescope would be way cool, but something about its etc. supposed capabilities has long bothered me. I question how ever-larger apertures can continue to provide ever better resolution with e.g. visible light – if they are simply accurate to within a given standard like 1/8 wave.

    In theory, in the ideal, I see why. But consider that as a mirror gets larger, the tiny variations in orientation of portions of the mirror should eventually cause errors greater than the ever-decreasing diffraction spot. IOW, consider e.g. that little portions of the 30-meter mirror have roughly random (how “random” isn’t the main issue) “orientation errors” of around 0.01 arc second. So if this mirror was idealized and we used hard UV at 50 nm, the theoretical resolution should be about 0.0003 arcsec. But application of geometric optics to the surface irregularities should mean, a circle of confusion 0.01 arcsec diameter. IOW, resolution is limited by surface traits and can’t be endlessly improved with ever-shorter wavelengths. The flip side ought to be, ever larger apertures should fail to provide ever-increasing resolution with the same wavelengths.

    OK, now switch to visible light. The theoretical resolution should be about 0.003 arcsec. Can that somehow be even better than the UV resolution, because of some global treatment of the larger waves? I find that hard to believe, because the centers of where diffracted portions of light are sent would still be directed to slightly different spots at the collection point, per the 0.01 arcsec variations.

    Maybe I misunderstand the implications of applying a “1/8 wave” etc, standard to different apertures, but I can’t imagine that as mirrors/lenses were made larger we’d be able to proportionately reduce the magnitude of orientation flaws. It would be absurd. We’re just making a bigger piece of the same stuff that someone must polish locally etc. (Also, the inherent physical grain.)

    Any scoop folks, especially on “who asked this first” etc?

  4. #4 steve hsu
    July 23, 2009

    “when Goldman comes knocking at your door with a deal, run, don’t walk screaming for the door!”

    Unless it’s an offer of employment :-)

    Some podcast recommendations: (all on iTunes)

    LSE public lectures

    Leonard Lopate Show

    Speeches in honor of John Searle (50 years at Cal) — this is hard to find but there is a link on my blog

    Also a guy called Marshall Poe (History prof at U Iowa) has an interview series with authors of recent history books. It’s quite good.

  5. #5 John Sidles
    July 23, 2009

    Dave, we musn’t overlook the bacon-related breakthrough being reported at The Neuroscience of Bacon McGriddles!

  6. #6 Jonathan Vos Post
    July 23, 2009

    Roukes rocks.

  7. #7 Rocky Humbert
    July 24, 2009

    I wonder whether Rourke’s approach is sensitive enough to detect the weight loss achieved during my recent diet & exercise regime?

  8. #8 Neil B ☺
    July 25, 2009

    In case my point above wasn’t clear: I am suggesting that the resolution of a mirror can’t be any better than as limited by either the ray tracing *or* the diffraction. IOW, both are limiting factors. Then, I suggest that we cannot make mirrors to unlimited surface consistency specs, of ever smaller angle-consistency from place to place as the mirror is larger. Hence, the circle of confusion from ray tracing will eventually outgrow the diffraction disk. That puts a rough lower limit on the resolution we can get from ever-larger mirrors.

  9. #9 Jonathan McKay
    July 25, 2009

    The Economist puts out their entire magazine in audio. If you don’t have a subscription, e-mail me and I can hook you up with a login. Even if you don’t like the regular reporting, I think the ‘special reports’ are almost always worth a listen.

    Also, if you have any ambition of learning a language, podcasts are a great way- though I only know the good ones for Arabic and Chinese.