Tuesday, March 06, 2012

NSF - proposal compliance

This is for everyone out there who submits to proposals to the Division of Materials Research, and more broadly, to the National Science Foundation. Here's some context for those who don't know the story. The NSF has a Grant Proposal Guide that spells out, in detail, the proper content and formatting for proposals. You can understand why they do this, particularly with regard to things like font size. There's a 15 page limit on the "Project Description" part of a proposal, and if they didn't specify a font size and margins, there would be people trying to game the system by submitting proposals in 6-pt unreadable font with 1cm margins. Historically, NSF has erred on the side of latitude about the minutiae, however. For example, they have never really been aggressive about policing whether the bibliographic references are perfectly formatted.

That's why this news came as a surprise: As part of a new policy, starting this past fall, DMR is taking basically a zero-tolerance approach regarding compliance with the Grant Proposal Guide. That means, for example, that any letter of collaboration included with a proposal can only say, in effect, "I agree to do the tasks listed in the Project Description". Anything more (e.g., context about what the collaborator's expertise is, or mentioning that this continues an existing collaboration) is no longer allowed, and would be cause for either deletion of the letter or outright rejection of the proposal without review. This new policy also means, and this is scary, that your references have to be perfectly formatted - leaving out titles, or leaving out the second page number, or using "et al." instead of long author lists - all of these can lead to a proposal being rejected without review. I heard this first hand from a program officer. Imagine spending weeks writing a proposal, and having it get bounced because you used the wrong setting in bibTeX or EndNote.

We can have a vigorous discussion in the comments about whether this policy makes much sense. In the meantime, though, I think it's very important that people be aware of this change. The bottom line: Scrupulously follow the Grant Proposal Guide. Cross every "t" and dot every "i".

Please spread this information - if one division of NSF is doing this, you can bet that it will spread, and you don't want to be the one whose proposal gets bounced.

Sunday, March 04, 2012

March Meeting last day and wrap-up

Not too much to report from the final day of the March Meeting. Lots of good conversations with colleagues, though I never did get a chance to sit down with a couple of folks I'd wanted to see. Ahh well.

I split most of my time between two invited sessions. The first of these was on the unusual properties of the nu=5/2 fractional quantum Hall state. This may sound very narrow and esoteric, but it is actually quite profound. A good review of the whole topic in more generality is here. At a very particular value of perpendicular magnetic field (related to the number of charge carriers per square centimeter), the electrons in a 2d layer in GaAs/AlGaAs semiconductor structures apparently condense into a really weird state. The lowest energy excitations of this state, its quasiparticles, have very strange properties. First, they have an effective electronic charge of 1/4 e. Second, when two of these fractionally charged quasiparticles are moved around each other to swap positions, the whole quantum mechanical state of the system changes (to another state with the same energy as the original), in a way much more complex than just picking up a phase factor (which would be -1 if the quasiparticles acted like ordinary electrons). Somehow the detailed history of winding the particles around each other is supposedly encoded in the many-body state itself. Quasiparticles with this bizarre property are said to obey "non-Abelian statistics". To date, there has not been an experimental "smoking gun" demonstrating these weird properties unambiguously. My postdoc mentor, Bob Willett, gave a very data-heavy talk showing persuasive evidence for consistency with a number of the relevant theory predictions in this system. Following him, Woowon Kang of the University of Chicago showed other data that also looks consistent with some of these ideas (though I'm no expert).

The other invited session dealt with the theory behind the transport of electrons and ions in nanoscale systems. Unfortunately I missed the beginning (since I was seeing the other talks above), but I did get to hear a neat discussion by Kirk Bevan of McGill University about the physics of electromigration. Electromigration is the mechanism by which flowing electrons can scatter off defects and grain boundaries, dumping momentum into atoms and pushing them around.

Final suggestions for the APS:
1) Don't have the small rooms arranged so that getting to seats in the front requires blocking the projector. The result of that is that the front 6 rows or so remain almost completely empty, while people pile up in the back of the rooms.

2) Would it really be that hard to have wireless internet access that doesn't suck? Are there no convention centers that can really support this?

3) Having a big bio presence at the meeting and then scheduling it directly opposite the Biophysical Society meeting seems odd.

4) Every year, there is an electronic letter-writing or petition campaign to support federal funding of research. That's fine and dandy, but is there any way we could try to get some representative Congress-critters to come hear a session, perhaps one of the fun, general invited sessions, or one about industrially relevant research? Remember, next year in Baltimore is quite close to DC....

Friday, March 02, 2012

March Meeting day 3 (for me)

Yesterday I spent a fair bit of time seeing specialized talks related to my group's research. In the contributed session in the morning, I saw a couple of talks by the theory group of Kevin Ingersent at the University of Florida. When describing electronic transport through a molecule, there are two basic theory approaches. One way to tackle this problem is to try to do realistic quantum chemistry calculations about specific molecular orbitals and how a molecule couples electronically to metal electrodes. A complementary tactic is to construct a mathematical model that you think contains the essential physics (e.g., treat the molecule as a "dot" with two electronic levels, each coupled to generic conduction electrons in the leads; then add in a single, local harmonic vibrational mode with some coupling between the level populations and the amplitude of the vibration, etc.). These two schemes correspond well with approaches to bulk materials: realistic electronic structure calculations vs. construction of model Hamiltonians. Ingersent's group takes the latter approach, and it looks like there is even more rich physics buried in single-impurity junctions than I'd previously appreciated.

In the same session, there were some nice experimental talks from Latha Venkataraman's group at Columbia. Recently, her students have seen that it's possible to create comparatively good contacts between molecules and metals, with a single quantum channel being transmitted through the system with a transmission of about 90%. This is in contrast to the more common situation, where transmission is more like 0.1%. She's also started doing single-molecule measurements of thermopower and Seebeck coefficient, where you apply a temperature gradient across a molecule and look at the resulting voltage difference that shows up. Cool data, though thermal transport at these scales is very challenging.

Later in the day I heard some nice invited talks. Jean-Marc Triscone gave a nice presentation of the properties of the two-dimensional electron gas that shows up at the interface between strontium titanate and lanthanum aluminate (STO/LAO). This field of oxide heterostructures has become very popular, and includes all sorts of rich physics, including coexistent superconductivity and magnetism. Any topic that gets to talk about a "polarization catastrophe" has to be good.

In another invited session, Cyrus Hirbijehedin talked in detail about Kondo physics in single magnetic atoms on very thin insulating layers, as probed by STM. Dan Ralph gave an extremely clear talk (via iphone from Cornell, due to inclement weather) on Kondo physics in single-molecule junctions, with their particular experimental twist of being able to stretch or squish the junctions in situ. Very neat. There are some lingering technical points in such structures that need further examination by the community.

I did not, unfortunately, see Leo Kouwenhoven's ballyhooed (here and here) talk about Majorana fermions. I need to read more about the particular work before I can offer any intelligent commentary.

Wednesday, February 29, 2012

March Meeting day 2

Today was probably the maximum crowd at the APS meeting. Saw a number of talks and had lots of conversations. One particularly interesting talk was about variations on this result. In condensed matter we've become used to the idea of "photonic band gap" or "photonic crystal" materials, systems where a spatially periodic pattern of dielectric contrast (e.g., glass vs. air) results in optical properties that mimic the electronic properties of crystals: bands (energy ranges) where light can propagate freely, and (photonic) band gaps, where light is reflected and can't propagate. This talk was about weird "hyperuniform" disordered dielectric structures that nonetheless have a complete photonic band gap (in all directions) in 2d, and the fact that by introducing voids and defects in these systems, it's possible to make very selective and directional waveguides. I need to read more about the math behind this. The experiment uses microwaves rather than visible light, meaning that it's possible to build such structures by hand using sapphire plates and rods on the centimeter scale.

The Buckley Prize session was also very good, though I missed talks in the middle. Very crowded, particularly for Charlie Kane's talk. That one would have been fun if it'd been a full hour - it felt like he had to abbreviate some of the discussion to fit into the 30+6 minute slot.

Another highlight this afternoon was the big Kavli session about the mesoscale. The lead talk was from Bob Laughlin, who is always entertaining. He focused on the big open question of whether there are laws that emerge in biology. By his definition, a law is a quantitative relationship between measured parameters that always holds. Some laws are (apparently) fundamental, like the force between two point charges in vacuum. Others are emergent, like the relationship between stress and strain in elastic media, or the Navier-Stokes equations that govern hydrodynamics. In the emergent situation, emergent laws hold when the system is sufficiently macroscopic. Laughlin's big question is, are there universal quantitative relationships that emerge in biological systems (beyond the trivial ones already mentioned, like elasticity being useful for describing cell membranes)? He says that there are hints all over, but it's very hard to do the definitive experiments because biology is just so complicated and our experimental tools are comparatively invasive and crude. When asked to describe biologists in one word, he said "frustrated".

The talk also put forward two definitions of what condensed matter physicists do, both of which are very good. Via Laughlin, Michael Fisher says: "Our job [as condensed matter physicists] is to discover and understand the phases of matter and the transitions between them." Laughlin himself says: "Our job [as condensed matter physicists] is to discover the emergent laws of nature, and hand them to engineers so that they can be put to use." Good stuff. On a lighter note, I realized partway through the talk that every now and then it's entertaining to imagine Laughlin's words as if said by William Shatner. "We trust the emergent laws of rigidity and hydrodynamics...to make an airplane...that can go up to 35000 ft...and not...explode!"

March Meeting day 1

As I am every year, I was again somewhat shocked by how many people come to this meeting. The attendance just keeps going up, and unfortunately that usually correlates with a decrease in the utility of the average talk. For PIs, the meeting is more about interacting with each other, vendors, potential hires (postdoc or faculty) than it is about actually learning things from talks.

I did actually learn a few things in talks yesterday, though, even without going to sessions on the super hot topics (graphene, topological insulators).

I went to the first half of an interesting session about presenting science to the public, something that I think is very important. The first talk was about a theater group collaborating with MIT, with a history of developing plays based on physics (including Einstein's Dreams by Alan Lightman). Here, free of charge, are my suggestions for other play possibilities: The birth of Silicon Valley, emphasizing that in many ways it stems from the fact that Shockley was such a micromanager that no one could work with him; the genesis of the hydrogen bomb, emphasizing that Teller's difficult personality delayed the development of his much-loved "super" by at least two years, because very few people could work with him. (Sense a theme?). The second talk was by Odd Todd Rosenberg, an animator who works with Robert Krulwich of ABC and NPR science fame. The cartoons were funny and informative, though the discussion raised the recurring issue of oversimplification and inaccuracy in broadly popular marketing of science.

I also went to a very strong session all about vanadium dioxide, which was quite informative. Sounds like many people in the strong correlations game are starting to look very hard at ionic liquids for gating. Here the major challenge is whether people are inadvertently (or advertently) doing chemistry on their structures.

There was also a very fun talk by Hongkun Park of Harvard, who discussed "quantum plasmonics" - trying to couple individual emitters and absorbers to plasmonic waveguides. For example, you can have a GaAs nanowire touching a silver nanowire. When biased appropriately the GaAs emits photons which couple strongly into guided plasmon modes of the Ag wire, propagate as plasmons, and are then generate photocurrent at a junction with a Ge nanowire at the other end of the silver wire. This is a "dark plasmonic" circuit, with light being generated, propagated, and detected on the subwavelength scale. Cool stuff.

Monday, February 27, 2012

March Meeting program and app

For an organization so deeply ingrained with technology, the American Physical Society has some surprising issues. For example, as I type this, I'm downloading the complete program to the March Meeting at the blazing pace of 5 kB/s, and that's not limited by my connection. For another example, once again the APS has released a mobile app that contains the whole program and is supposed to be searchable. Unfortunately, the user interface on the app (at least the ipad version) is dreadful, unintuitive, and creepingly slow. Geez.

Sunday, February 26, 2012

Job interview humor.

Thanks, Wolff, for pointing me to this.

Coming up this week, some commentary from the March Meeting of the APS.

Thursday, February 23, 2012

superluminal neutrinos - not (quite) dead yet.

When historians of science look back on the whole OPERA superluminal neutrino discussion, one way or the other, there are going to be a number of lessons to draw from the experience about how science and science journalism function in the early 21st century.

Yesterday, with "BREAKING NEWS" headlines, Science magazine proclaimed: "Error Undoes Faster-Than-Light Neutrino Results". In that article, "according to sources familiar with the experiment", the whole timing discrepancy for the neutrinos is traced to a bad fiber optic connection to a GPS receiver. The claim from that article is that "After tightening the connection then remeasuring the time it takes data to travel the length of the fiber, researchers found that the data arrive 60 nanoseconds earlier than assumed." Since that's the critical amount by which the neutrinos allegedly arrived too soon for special relativity, that would seem to be the end of the story. Embarrassing for OPERA, but case closed, right? T

Wrong. First, on its face, this seems weird - no one is quoted by name, and the idea that a loose fiber coupling could contribute 60 ns in timing is pretty odd (since that would correspond to something like 18 m of free space optical path). At minimum, the description above must be garbled.

Moreover, the actual email from the CERN director does not say this at all. Rather, it says that OPERA has identified two outstanding issues, one involving an oscillator that provides timestamps for the GPS synch, and an optical fiber connector that brings the GPS signal to the OPERA master clock. The former issue could make the neutrino timing problem worse, in fact. Moreover, the message says explicitly that they are going to take new measurements in May to check these issues. That seems to flatly contradict the news article claiming that they've already done tests. For a detailed discussion, see Matt Strassler's excellent blog here.

Bottom line: as I've said before, the superluminal neutrino result is almost certainly wrong, but the jury is still out on how and why, despite what the Science news blurb says. Believe me, if they knew for sure how this stood, they'd end it with a definitive statement, not stretch this out 'til May.

UPDATE:  Prof. Strassler has the best write-up of this, based on detailed reporting from the European press.   Because of two different, subtle technical flaws, the uncertainty in the OPERA results is bigger than the 60 ns timing discrepancy, meaning (1) the result is not in contradiction w/ special relativity (big surprise), and (2) they need to run with fresh data and the problems rectified to make any more definitive statement.