Tuesday, April 29, 2008

Copying text without attribution is plagiarism.

Amazingly, there are graduate-level students out there who do not understand this simple, basic fact. When you're writing a scholastic or scientific document, you never copy other people's words - certainly not complete verbatim sentences - without clear attribution and indication that you're quoting someone else. You just don't. Ever. Doing so is plagiarism, and as any kind of professional you should know that it's wrong. Amazingly, some students don't seem to get this point, even when they've been told about this, explicitly, repeatedly, and actually signed documents attesting that they understand this, and when they know that the professor can use this amazing tool called google to figure this sort of thing out.

Just. Don't. Do. It.

Friday, April 25, 2008

Come on, AAAS

I'm a member of the AAAS, in part because I support their various efforts, and in part because I like my subscription to Science. However, at least three times a year, I get junk mail at my house or at my departmental address, asking me if I'd like to join AAAS for the low new-member rate of $99/yr. How can these geniuses not realize that I'm already a member? I have an unusual last name, and they already have both my work and home addresses on file. Can't they tell that Prof. Douglas Natelson and Mr. Douglas Natelson with identical addresses are the same person? They must waste hundreds of dollars in postage and thousands of pieces of paper doing this, since I'm sure I'm not the only one getting these useless mailings. Good grief, folks, just do a sensible search on your mailing database for duplicates.

Thursday, April 24, 2008

AMO physics coolness

I saw two things in Science this week that I found quite interesting. First was a mention in Editor's Choice of this paper from my old stomping grounds at Stanford. The arxiv version is here. The idea is another great example of using essentially table-top physics (if you have a large, stainless steel vacuum chamber and lasers on your table) to test the limits of the Standard Model of particle physics, usually the domain of the high energy folks. Here's the story: there are many weird alternatives to the standard model where things like charge quantization (the idea that charge comes in chunks of exactly -e for electrons, and +e for protons, for example) and charge neutrality are approximate rather than exact, due to the breaking of some far out symmetries at very high energy scales. This paper points out that this idea can be tested very precisely (to 1 part in 1028) using interferometry of Bose-condensed atoms. In an optical interferometer, light (consider only one particular color) is split into two beams that take different paths, and then recombined. As light travels on each path, you can figure out how much phase the light waves accumulate by dividing the pathlength by the wavelength (and multiplying by 2 pi if you want your phase to be in radians). The intensity when the beams are recombined is proportional to the cos of the phase difference between the paths. This can be an incredibly precise way of measuring relative path lengths, and is essential to lots of modern technology. In the proposed experiment, the Bose-condensed atoms act like matter waves, and the idea is to do the same thing. However, in quantum mechanics the phase difference that builds up is related not just to the path length, but also picks up a contribution due to the (integrated) difference in (potential) energy (times time, divided by hbar) between the two paths. This is the way AMO and neutron interferometry measurements of gravity work: send waves along paths at different heights and recombine them, and the phase difference will include a contribution proportional to (m g h) where m is the mass of the particles, g is the gravitational acceleration, and h is the height difference. In the proposed experiment the atom waves are sent through regions of different electrostatic potential (voltage). If the atoms aren't exactly neutral, the voltage will couple to their charge and lead to a phase difference that would otherwise be absent. It's very elegant, and may be a way to test advanced high energy ideas without TeV particle accelerators.

The second bit that I read was this article about the race to use cold fermionic atoms trapped in optical lattices as a means of implementing condensed matter models of interesting systems (e.g., the Hubbard model of high-Tc superconductors). The theoretical models are computationally nightmarish to solve exactly, in large part because of the Fermi-Dirac statistics problem that the correct many-body wavefunctions must pick up a minus sign if the positions of any two electrons are swapped. The plan is to implement what are basically analog computers - cold atom systems that can be poked, prodded, and tuned - to map out the solutions. Using tunable model systems to explore strong correlations in quantum matter also happens to be the focus of Rice's Keck Program in Quantum Materials. (One note for regular commenter Sylow: now do you believe me that there is a DARPA program on this?)

Sunday, April 20, 2008

Career comments

Well, it's that time of the year again. Lots of blogging (here , here, here, here) about advice to tenure-track faculty (and other interested parties) about the tenure process. I've decided to dust off a post I originally made last May, with a few revisions and additions, to contribute to the discussion.

In terms of the job pipeline, the biggest cut in population happens when trying to get a faculty position, not at the tenure stage. In reasonable departments, no one is happy when a tenure promotion case fails. Good departments (and schools and universities) try very hard to filter at the hiring level and give their faculty the resources they need to succeed. I can only think of two or three places (in physics anyway) that historically have had a "sink or swim" attitude (that is, hiring a junior person in an area today means that seven years from now the university wants the best senior person in the world in that area - being in-house is not advantage), and I'm not sure that's even true anymore.

Generally advice is not in short supply, though good advice can be. Many institutions are setting up official mentoring efforts to ensure that junior candidates have people to talk to about these issues. A colleague of mine found several nice documents online about this issue of advice-giving and receiving. This one (pdf), from the ADVANCE program at the University of Michigan, is particularly good. I am hardly in a position to give too much sage advice about tenure, and what follows below is largely common sense. Obviously the situation is different in various disciplines and at different universities, but here's some basic points that I think should be considered. I'm sure I'll leave things out - feel free to chide me in the comments.

Understand the process. Find out how the tenure process works at your institution. This should be written down in a faculty handbook. Talk to your department chair, your faculty mentor (if your department has such a thing) or senior colleagues. Understand the timeline. Get a sense of the weight that your institution places on the different components of the job (see below). Does the departmental vote carry a lot of weight (as it usually does at Rice, for example), or are the deans or the university promotions and tenure (P&T) committee commonly overriding departmental decisions?

The process probably goes something like this: the candidate is hired for a 4-year tenure-track appointment, with some kind of annual reviews and a more major renewal review in year 3 or 4. (This gives the university a chance to end the process early if there's a major problem with an assistant prof, and forces departments to give some concrete feedback to the assistant prof about how they stand.) In the summer before year 6 (at most places) the candidate is asked to put together a dossier (complete CV, reprints of papers, a summary of funding, a statement about university service, a statement about teaching, a summary of research accomplishments, etc.) and suggest names for external evaluators. The department comes up with additional names for external evaluation, and sends the full dossier to some mix of the external people. Eventually these external letters come back, and the department reads them, puts the whole package together, and there's a vote of the tenured faculty (in October or November) about whether to recommend the assistant prof for tenure. The departmental recommendation then goes to the cognizant dean, and from there to the university P&T committee (which generally would have people from all sorts of disciplines on there, from bio to French lit). Sometimes P&T committees or deans can request more external letters, and they get copies of teaching evaluations, etc., and may meet directly with department chairs. Eventually the P&T committee makes its decisions (in late spring) and the candidate finds out. That decision is finally signed off by the president of the university and the board of trustees.

The research component. To get tenure you need actually need to be getting science done. There's no sure-fire recipe for success here, but let me make a few suggestions:
  • Have a mix of projects that range from easier to high-risk/high-reward. Having only one major project can be very risky, particularly if it takes five years to get any results. One key element of getting tenure is that people in your community need to know who you are, what you've done, and what you've been doing that's really yours - new stuff from your professorial position, not rehash of your thesis or postdoc work.
  • Make sure that your colleagues know what you're doing. Your colleagues are going to need to understand your work at least on some level, and particularly for hard projects, they will need to have some idea why it may take four years before a paper comes out.
  • Have backup plans. High risk things may not succeed (no kidding.). Make sure, for your students' sake and yours, that you have thought out the projects well, so that even if you don't achieve the BIG goal, you are still learning useful things that are worth publishing.
  • Have a high attempt frequency for funding. If there's literally only one agency in the world that funds your work, that's risky and unfortunate. Make sure that you know what your options are for funding sources. Call up program officers. Ask to get a chance to serve on review panels - you'll learn a huge amount about writing proposals that way! Know if there are state funding opportunities. Think ahead about private foundations (e.g., Research Corporation).
  • Do some self-promotion but don't sell your soul. If your external evaluators don't know who you are, that's the kiss of death. Make sure you give talks at meetings. See what you can do about getting invited to give seminars at other schools. Yes, this is one issue where "well-connected" people really benefit, but if you go to meetings and get to know the people in your field, it's not that bad. Get involved in your own department's seminar series, and invite in people that you'd like to meet and talk to.
  • Publish good stuff. This is always the tricky bit, and people joke about the "least publishable unit". Still, holding back everything for the one big Nature paper that may not happen is not necessarily the best strategy, for you or your students.
  • Get stuff going relatively quickly. Think about the timescales associated with publications and citations. Even if you do the greatest piece of work in your field ever, if you don't get it out the door at least a year or two before your tenure review (that is, a year before letters get sent out to external reviewers), it's going to be very hard for that work to have had much of an impact by the time of the decision.
The teaching component. Do a good job teaching. Most universities have resources available to help you - teaching centers that will videotape your lectures, offer suggestions for improved technique, etc. Good teaching can only help tenure in limited ways at a research university, but poor teaching can certainly hurt a borderline case. People joke that getting excessively good teaching evaluations is a sign of misallocated time. That's not necessarily the case. The skills that you learn to be a good lecturer in the classroom overlap quite a bit with the skills you need to present research well - organization, an appreciation for your audience's perspective and knowledge, clarity, etc.

The mentoring component. This is related to both of the above. It definitely helps make the case that you are running a successful research and education enterprise if you can actually graduate students. This means making sure that they are making real progress, publishing papers (and/or patents), and ideally enabling them to land a good job (postdoc or industry) afterwards. This is not just altruistic; it's also enlightened self-interest - if you build a reputation for getting good people out in a reasonable timeframe and with real job prospects, it will help in graduate and postdoc recruiting in the long term. Managing a group isn't easy, and every student is different. If you feel like you're having trouble, definitely find colleagues to ask for advice! Every faculty research mentor has been there.

The service component. Do a decent job in departmental and university service. Don't let it eat all your time, but get involved in things that matter to you. It's also a good way to get to know your administrators and people in other departments. I'm not suggesting currying favor - just be a solid citizen. Becoming known as a pain-in-the-ass on this is not going to help you on any level.

Common sense. People argue about whether blogging can hurt your tenure chances. Blogging is only one example of a public forum, though. Use some common sense. Publicly badmouthing your institution, colleagues, administrators, etc. is not a good idea. (I'm not talking about hushing up legitimate grievances - I'm saying don't antagonize people gratuitously.) Remember, in a practical sense, the tenure decision is based not just on your scientific quality, but on whether you are the kind of colleague that people want to have for the next n years.

Don't panic. At some point, you just have to buckle down and do the work without inducing a psychodrama about the process. If you've been in a graduate program, you've undoubtedly known someone who, rather than actually solving their research problems, spent their time kvetching about how nothing was working. Don't do that to yourself.
Remember, you're doing this because you enjoy it intellectually (at least, some of the time!).

Sunday, April 13, 2008

Talk this week

First, to the readers of this blog, thanks for the recent trend of posting informative links in the comments. I think that this really adds something to the discussion. One tip: in the comments you're allowed to use html tags, so if you want to post a link with a long URL, you may want to write the html that actually posts the link.

This week we had a fun physics colloquium given by Paul Canfield of Ames Lab and Iowa State University. He spoke about the discovery and characterization of new materials, with a particular emphasis on heavy fermion compounds, but with a significant discussion of MgB2 as well. His main purpose was to convey how physicists like him think and approach problems, and I think he succeeded. He also had a funny slide called "Periodic Table According to Most Physicists" that looked roughly like this:

H H' (almost like hydrogen)
H'' H''' C H'''' H'''''
Metals Cu


Elements that may not even be real

|<---Not on the final exam --->|
|<---Stuff for bombs -------->|

Amusing stuff.

Friday, April 11, 2008

Your tax dollars at work.

Like many of my colleagues, I review lots of grant proposals. Recently I was asked to review one for the Department of Energy, and when I said 'yes', they sent me the proposal. By Federal Express. On a CD. Now, you might wonder why, if they don't mind me ending up with this in an electronic format anyway, and if they want me to send in my review electronically, they wouldn't just handle this purely over the web, and save the money and environmental impact of shipping a CD from northern VA to Houston. Ahh well.

Friday, April 04, 2008

Talks this week

I saw some very good talks this week. First up was a physics colloquium by Stuart Parkin from IBM Almaden. In some very real sense, you're reading this because of Parkin - he and his team were the people who first took giant magnetoresistance (GMR) and developed it into a useful technology in the read heads of hard disk drives. The remarkable explosion in data storage capacity over the last decade and a half is largely due to this advance, possibly the best example of true nanotechnology (the film thicknesses involved in spin valves are a few nm) making it out of the lab and into manufacturing and consumer products. Their later work on tunneling magnetoresistance has also now been transferred into hard drive read heads. In fact, TMR heads with MgO tunnel barriers between ferromagnetic layers can have room temperature resistance changes of several hundred percent in the presence of few-Oersted fields like those from drive media. After reviewing all of this at just the right level, Parkin went on to talk a bit about his latest ideas and work on high performance "racetrack" memory. In this idea, a single transistor cell can be responsible for reading and writing tens of bits of memory (as opposed to one in current RAM designs). The bits are stored as domain walls in a ferromagnetic nanowire. The walls can be detected through their local change in the magnetization, and they can be moved by pulsing spin-polarized currents through the ferromagnetic wires. All in all, a great colloquium - one of my colleagues wished that we'd taped it so that we could show it to job candidates as an example of a real general audience colloquium.

There was also a workshop on campus this week about probabilistic and nanoscale computing that featured some nice talks. One of the best was by Tom Theis, head of physical sciences research at IBM, who reviewed their latest developments and the future of the field-effect transistor from his perspective. Anyone who has alternative ideas in mind about computing technologies really needs to do their homework by listening to someone like Theis, who has perspective about the science as well as the economic and manufacturing issues.