Monday, December 26, 2005

Stem cells and Jan Hendrik Schon

Unless you're living under a rock, you've heard about the scandal unfolding involving Dr. Hwang Woo Suk of Seoul National University. He is the world-famous scientist now accused of falsifying his stem cell research, the most recent paper of which had been published in Science. I want to point out something that has been entirely neglected in the media, as far as I can tell: the amazing similarity between this and the J. Hendrik Schon fiasco. For example:

* Huge impact articles in major journals, with talk of Nobel prizes.
* Multiple big-name coauthors who did not spot anything wrong.
* Progress in an exceedingly demanding field far in excess of reasonable expectations, yet attracting no suspicion at the time.
* The first hints of impropriety raised due to duplication of figures (!), a sloppy mistake virtually guaranteed to be noticed eventually.
* Immediate denial by the PI, with claims that the whole problem comes down to poor record keeping.
* Initial institutional announcements that while some particular result may be flawed, the body of work is still good, pretty much because the PI is a "genius".
* Claims by the PI in the face of mounting evidence of fraud that the results are true.
* Complete denial of any responsibility by the journal editors, who may or may not have downplayed negative referee reports because the results are potentially so important.

Interesting, eh?

The most important similarity in both cases, of course, is that they got caught - the scientific process did work, albeit slowly.

One other comment: I hate it when ethicists insist that the real problem is the lack of formal ethics training in the scientific curriculum. That is absolute garbage. Does anyone really think that Hwang or Schon didn't realize what they were doing was wrong? Does anyone really think that one more ethics course would have prevented either case? Come on. Seriously.

Tuesday, October 04, 2005

A long break....

Sorry for the long break. It's been a very busy time in academia. I did finally finish my 100 page review article about single-molecule transistors, though. I also spoke at the Bat Sheva Seminar on Electron Transport in Molecular Junctions, possibly the best scientific meeting I've ever attended.

I heard two striking things at the meeting. First, Europeans and Israelis were shocked at how much time Americans spend writing grant proposals. Interesting. Second, there are still real problems in our understanding of interfaces at the atomic scale, and charge transfer. There is even still debate about whether the theory prediction vs. experimental data divide is converging. On the side saying that real progress is being made are folks like Stuart Lindsay and Mark Ratner. Those arguing that there are still major discrepancies include Amir Yacoby. Fascinating discussions.

I'll discuss a couple of specific recent results next time.

Thursday, August 11, 2005

Least action and non-classical paths

Here's a funky piece of physics discovered in condensed matter research that deserves broader attention because it is so weird.

So, the Feynmann-Hibbs path integral approach to quantum mechanics says that the way to calculate the probability of a quantum system starting at configuration {a} and ending at configuration {b} is to add up the complex amplitudes for all possible paths between {a} and {b}. For each path, you can compute the classical action, S, by integrating the Lagrangian along the path, and the amplitude for such a path is given by exp^(i S / \hbar). This is particularly nice because paths that extremize S end up constructively interfering (having very similar phases). So, when one passes to the classical limit (\hbar -> 0), one finds that the dominant classical trajectory for the system is the one that extremizes the action. Unsurprisingly, the trajectory that dominates is something smooth that looks like a sensible classical path (e.g. for a particle propagating in free space, it's a straight line from point a to point b).

Here's the weirdness, though. There is at least one system (quantum tunneling of spin in molecular magnets) for which the action-extremizing paths are discontinuous. In our free particle discussion, these would be analogous to trajectories where the particle's path in space looks like _____----____--__ , complete with discontinuous changes in coordinates. Such trajectories are always in the calculations (in fact, in quantum field theory you need to include paths with space-like discontinuities (!) in order to get the calculations to come out correctly), but this is the only case I've ever seen where they can be the dominant trajectories.

Monday, August 08, 2005

Intelligent design

Thank goodness the President doesn't really have much to do with setting educational practices in this country. From the transcript of his Aug. 1 press event in the Roosevelt Room at the White House:

Q I wanted to ask you about the -- what seems to be a growing debate over evolution versus intelligent design. What are your personal views on that, and do you think both should be taught in public schools?

THE PRESIDENT: I think -- as I said, harking back to my days as my governor -- both you and Herman are doing a fine job of dragging me back to the past. (Laughter.) Then, I said that, first of all, that decision should be made to local school districts, but I felt like both sides ought to be properly taught.

Q Both sides should be properly taught?

THE PRESIDENT: Yes, people -- so people can understand what the debate is about.

Q So the answer accepts the validity of intelligent design as an alternative to evolution?

THE PRESIDENT: I think that part of education is to expose people to different schools of thought, and I'm not suggesting -- you're asking me whether or not people ought to be exposed to different ideas, and the answer is yes.

Sigh. The President clearly doesn't understand that "Intelligent Design" is not science. It is unfalsefiable. It makes no predictions - it makes assertions. Saying that it deserves something like equal time with evolution in school science classes is absurd.

It's tempting to make an inflammatory statement that this demonstrates the anti-intellectual, anti-science attitude of the current administration (i.e. the "faith-based" community vs. the "reality-based" community). However, I'd be shocked if the President actually gave this that much thought; I suspect science funding and science policy (apart from firebrand issues with his base like stem cells and missle defense) rarely, if ever, cross his mind. In some ways, that's even more sad than a deliberate anti-science attitude: if it doesn't serve political ends, he just doesn't care.

Friday, July 22, 2005

The Templeton Foundation

There was an interesting story this morning on NPR about the Templeton Foundation and their efforts to fund physics research. The Templeton folks are interested in the interface between science and spirituality, and sponsor the Templeton Prize (which is intentionally larger than the Nobel). The occasion for this story is an upcoming conference at Berkeley in honor of Charles Townes' 90th birthday, sponsored by the Templeton Foundation. I know about this because, like pretty much all of my peers, I received an announcement about a Young Scholar's competition being held at this meeting.

I have no problem with increased dialog between science and religion, as long as people remember where the boundaries are. "God did it" is a rather inquiry-ending proposition to hold in a scientific investigation, so I prefer to assume that non-supernatural explanations exist for the world around me and go from there.

Anyway, the story is interesting food for thought. Physicists talked to who are skeptical of the Templeton Foundation's motives include Sean Carroll and Lawrence Krauss.

Wednesday, July 20, 2005

Science and today's politics

Rep. Joe Barton (R-TX), chairman of the House Committee on Energy and Commerce, has decided to threaten NSF-funded scientists who authored a peer-reviewed, published study on climate change that suggests that fossil fuel consumption influences global warming. Specifically, he has requested that these scientists turn over all records of their work to his committee, where (quoting Barton's letter to the director of the NSF) "The term 'records' is to be construed in the broadest sense ... whether printed or recorded electronically or magnetically or stored in any type of data bank, including, but not limited to ... summaries of personal conversations or interviews ... diaries ... checks and canceled checks ... bank statements." For more information, see the New York Times and BBC articles on the subject.

It is a huge understatement for me to say that I find this disturbing. Asking scientists to essentially open their personal financial records to him because he doesn't like their research is appalling. We all sign "conflict of interest" disclosure forms when we accept research funds - threats of congressional subpoenas are not the appropriate way for Barton to voice concerns about the objectivity of researchers! Indeed, given that Barton's campaigns through the years have been massively financed by the oil and energy industries, if anyone's objectivity should be of concern, it's not that of the scientists.

I am genuinely concerned that even writing about this in a public forum potentially puts my future funding at risk. It is only a short step from Barton's current actions to some future move to political litmus tests for research funding (i.e. Why should tax dollars go to someone who holds views contrary to those of the current administration?). To some degree this is already happening. Read this (go to the full report link (pdf) and read page 26.).

The whole point of the peer-review system is that scientists have the appropriate training to evaluate the work of other scientists! At a time when American preeminence in science and engineering is slipping (pdf), and when research funding in real dollars (let alone as a percentage of GDP) is being cut, is politicizing the process at all a smart thing to be doing?

Friday, July 08, 2005

Interesting recent papers....

Here are a couple of interesting papers I've seen in the last week or so:

Doh et al., Tunable supercurrent through semiconductor nanowires, Science 309, 272 (2005).

Very pretty use of InAs semiconducting nanowires grown by the now-usual VLS approach, and contacted by aluminum pads. When the Al goes superconducting, carriers in the InAs (controlled via field effect with a gate) become superconducting, too, via the proximity effect. Basically this results in a tunable Josephson junction with the InAs nanowire as the controllable weak link. Gorgeous, as is most of the stuff that comes out of Delft.

Ghosh et al., Zero-bias anomaly and Kondo-assisted quasi-ballistic 2d transport.

A preprint out of the Cambridge folks that looks at very clean mesoscale 2d GaAs/AlGaAs systems and argues that there is evidence (a temperature-dependent zero-bias peak in the differential conductance) that points to Kondo-assisted transport in these systems. The remarkable thing is that the orthodox Kondo effect relies on localized spin degrees of freedom, and there shouldn't be any in these materials. The authors suggest a more exotic (2-channel!) Kondo effect involving localized two-level defects. Very intriguing data, though the interpretation is likely to be controversial, if past 2-channel Kondo reports are any indication.

Sunday, June 26, 2005

People who annoy me.

You know what really ticks me off? People with no technical background who have nonetheless become nanoscience and nanotechnology "talking heads". A lot of this is our fault - those of us who actually do research at these length scales. Why? Because we've done a lousy job of making sure that journalists can tell the difference between reality and hype. People on my "irresponsible talking head" list:

1) The Center for Responsible Nanotechnology. These folks act like a group who have put careful thought into the benefits and risks of nanotechnology. In fact, these folks don't have a physical science degree between them. I don't care how sincerely motivated you are, or how bright: if your idea of nanotechnology comes from reading nontechnical articles, you don't really know what's going on, and if you don't have the technical background to understand real technical articles, I am highly skeptical of your opinions.

2) Josh Wolfe. When he sticks to what he knows - giving investment advice about high technology companies - Josh Wolfe is as solid as they come. Very sharp. However, lately I've seen him making the rounds on CNBC and MSNBC talking as if he really is technically knowledgable about nanoscale science. He's not.

3) Michael Crichton. Apart from the massive plot holes in Prey, what really annoys me about Crichton is that he writes "nonfiction" articles about his novels' topics that get widely circulated (like in syndicated newspaper inserts). He's such an egomaniac that he thinks doing research for one of his novels makes him as qualified as a real expert to expound on science. This is true of his nano novel Prey, and true of his environmentalism novel State of Fear. Dude: you're an author, not a polyglot genius of science. Get over yourself.

Thursday, June 23, 2005

"More" really is different.

Condensed matter physics gets a bum rap sometimes. Murray Gell-Mann referred to it as "squalid state" physics. Wolfgang Pauli called it "Physik der Dreckeffeckte", or "the physics of dirt effects". (That's particularly ironic since it's the Pauli principle that makes condensed matter at all tractable.)

In addition to being at the heart of essentially all modern electronics technology, condensed matter is actually much more intellectually profound than "junk" effects. As Phil Anderson pointed out in his now famous essay, "More is different". That is, large systems of smaller entities interacting through relatively simple rules can exhibit very surprising emergent, collective properties. For example, a single iron atom is pretty simple, but put a bunch together, and you end up with a rigid solid (!) that is also a metal (!) and, at ambient conditions, a ferromagnet (!). Try predicting all that a priori from the Standard Model of particle physics....

One of my former professors, Bob Laughlin, has written a good book on this subject. As a physicist it's tough for me to judge just how well it'll read to a lay audience, but I enjoyed it thoroughly. It's vintage Laughlin (who I once saw ask a seminar speaker, "It's late. We're all tired. Why should we care about any of this?!"), even if some of the Stanford anecdotes have some minor inaccuracies. Here's a
review from the New York Times. I don't agree with everything he says (pretty much he thinks "nano" work is, in general, buzzword-laden crap rather than addressing real scientific questions. Oh wait - maybe I do agree with him.), but it's a fun read.

Wednesday, June 22, 2005

A condensed matter physicist blog: why not?

I was googling around for something the other day, and came upon, a website that purports to be the home of "scholarly discussions of physics" on the web. Upon going there, I discovered that the definition of physics used there apparently referred only to high energy physics (e.g. string theory, loop quantum gravity, accelerator-based experiments) and astrophysics/cosmology.

I assumed that this was due to intellectual snobbery on the part of that community, and set off to find all the condensed matter / AMO physics blogs out there, only to discover that, as far as I could tell, there aren't any.

So, here we are. I'll try to start one, and we'll see where this goes. I'll try to clearly delineate between science-related posts and other stuff (my comments on the weirdness of junior faculty life, or public science policy, or humor). If there are a bunch of you out there blogging the interesting things in condensed matter, nanoscale science, or AMO physics, please post and let me know, so I can link to your stuff....

Now back to the omnipresent task of proposal-writing....