a recurring story

Five years ago, there was a controversy in the pages of Nature regarding this paper from 1993, the first to claim atomic-resolution chemical analysis via scanning transmission electron microscopy.  At issue was whether or not the data in the paper had been reprocessed (in response to referee concerns) in a legitimate or misrepresentative way, and whether the authors had been honest and forthcoming with the journal and the reviewers about the procedures they'd followed.  The reason that matters came to a head more than 12 years after the original paper was the appearance of a preprint in the arxiv and subsequently submitted to Nature Physics, sharing two of the authors of the original paper, with further questions raised about the handling and analysis of data and images.  This was all discussed clearly and succinctly by ZZ at the time.  Nature allowed the authors to publish a corrigendum, a correction rather than a retraction, regarding the original '93 paper.  This was sufficiently controversial that Nature felt the need to write an editorial explaining their decision.  Oak Ridge did an investigation of the matter, and concluded that there was no fabrication or falsification of data; that report and a response by the authors are linked here.  Judging from the appearance of this on the arxiv last night, it would appear that this isn't quite the end of things.

Pitch for a tv show

Summer blogging has been and will continue to be light, as I try to get some professional writing done. In the meantime, though, I have to give my elevator pitch for the awesome new TV show that would be great fun. It's "Chopped" meets "Mythbusters" meets "Scrap Heap Challenge"/"Junkyard Wars". Start off with three teams. Give them a physics- or engineering-related task that they have to accomplish (e.g., write the opening crawl from Star Wars in one mm^2; weigh a single grain of salt), some number of tools that they have to use (e.g., a green laser pointer and an infrared corrected microscope objective), and access to a stocked "pantry" (including a PC, electronics components, etc.). Give them a time limit (4 hours, cleverly edited down to half an hour in broadcast). Points awarded for success at the task, time used, and elegance. I think it could be a hit, particularly if there are explanations (narrated by cool resident experts) delivered in a fun, accessible tone. It'd be fun, even if it did conjure up images of Guy Fleegman in Galaxy Quest.

Soliciting book or review article recommendations

I am interested in reading good books or review articles on two particular topics, and I'm hoping that by "crowd-sourcing" to my readership, I might do better than wandering through the literature.  First, I want to find an authoritative discussion of the physics behind the electrochemical potentials of battery materials - not the lore of decades of electrochemistry, but a real hashing out of the physics.  Second, I would like to find a thorough, authoritative discussion of the physics behind catalysis.  Again, I'm not interested in handwaves and parametrized empirical knowledge, but would prefer a physics-based discussion that explains, e.g., why Pd is good at splitting H₂, while Ti is not.  Any help would be greatly appreciated.

Several items

I returned late last week from Germany, where I spoke at a summer school. One fun part of the trip was a tour of the main experimental facility at the neighboring Max Planck Institute for the Chemical Physics of Solids. The facility was a large high-bay lab space, with 9 (!) dilution refrigerator apparatuses, as well as a 0.3K scanning tunneling microscope with 12 Tesla magnet. Very impressive infrastructure, and the place was neat as a pin - the very model of a lab. Note to self: figure out how to instill Germanic ultraprecise lab notebook habits in all incoming grad students...,

Other news this week that is interesting: the US National Academies have decided to make many of their books available for pdf download free of charge. I'm a particular fan of one or two of these. For example, with reference to recent discussions about helium as a resource, check this out.

There is also a great deal of attention being paid to a paper from this week's Science by the group of Aephriam Steinberg. The experiment sends single photons one at a time through a two-slit type apparatus. This is one of those experiments meant to blow the minds of undergrad physics majors taking quantum for the first time: you still build up an interference pattern from the slits, even though there's only one photon in there at a time. That means the photon must be interfering with itself(!). In the new work, the group uses optics techniques (that I freely admit I do not fully understand) to correlate, after the fact, the ("weakly" measured) momentum of the photon while in the apparatus with the (strongly measured) final position of the photon on a CCD. This does not violate the uncertainty relation, since it basically finds a quantum mechanical ensemble average of the momentum as a function of final position. Still, very neat, and discussed in some detail here and here.

I've liked Steinberg's work for years. This business about quantum measurement and post-selection is very fun to think about. For example, this comes up when considering the question, "how long does it take a quantum particle to tunnel through a classically forbidden region?". What you're basically asking is, given the successful measurement of a quantum particle at some position beyond the classically forbidden region, when did the particle, in the past, impinge upon that region in the first place? This is a very hard question to answer experimentally.

Recently in the arxiv

As I get ready to head to Germany for my first ever experience lecturing at a Max Planck summer school, I wanted to point out very briefly three of a number of interesting papers that came through the arxiv this week.

arxiv:1105.4055 - Janssen et al., Graphene, universality of the quantum Hall effect and re-definition of the SI

This paper compares the quantization of the Hall resistance in two different two-dimensional electronic systems: a conventional 2d electron gas in a GaAs/AlGaAs structure, and graphene. The authors find that the Hall resistance is quantized in units of h/e² identically in the two systems to parts in 10¹¹. On the one hand, this is really amazing, since you're seeing essentially exact quantization in two different systems, and the whole basis for the quantum Hall effect relies in part on dirt - without disorder, you wouldn't see the quantum Hall physics. And yet, even though the materials differ and dirt plays an important role, you get precise quantization in terms of fundamental constants. This is the kind of emergent, exact phenomenon that shows the profound character of condensed matter physics.

arxiv:1105.4642 - Barends et al., Loss and decoherence due to stray infrared light in superconducting quantum circuits

As someone who struggled mightily in grad school to avoid the effects of infinitesimal amounts of rf noise leaking into his ultracold sample, this impressed me. The authors demonstrate that infrared radiation from the surroundings, even when those surroundings are at 4.2 K, can have marked, detectable impact on the coherence properties of superconducting quantum bits. They compare results with and without an absorbing radiation shield in the way, and the effects aren't small. Wild. Time to break out those 50 mK shields from our old nuclear demag cryostat....

arxiv:1105.4652 - Paik et al., How coherent are Josephson junctions?

Along these same lines, these authors have been able to demonstrate coherence times in superconducting qubits that stretching into the tens of microseconds scale. They do this via a new kind of cavity, essentially controlling the environmental dissipation. This isn't really my area, but I know enough to be impressed, and also to be surprised at the apparent lack of the usually ubiquitous 1/f noise problems (in the critical current) that often limit coherence in these kinds of devices. As they point out, these numbers are encouragingly close to the thresholds needed for quantum error correction to be realistic.

Nano for batteries

Improved batteries would be of enormous benefit and utility in many sectors of technology.  A factor of 10 improvement in battery capacity (with good charging rate, safety, etc.) would mean electric cars that get 1000 miles per charge, laptops that run for days w/o charging, electrical storage to help with the use of renewable energy, and a host of other changes.  This rate of performance enhancement is completely commonplace in semiconductor electronics and magnetic data storage, yet batteries have lagged far, far behind.

There is real hope that nanostructured materials can help in this area.  Three examples illustrate this well.  Conventional lithium ion batteries have an anode (usually graphitic carbon, into which lithium ions may be intercalated) and a cathode (such as cobalt oxide), with an intervening electrolyte, and a separator barrier to prevent the two sides from shorting together.  A reasonable figure of merit is the capacity of the electrodes, in units of mA-h/g.  The materials described above, anode and cathode, have capacities on the order of 200-300 mA-h/g.  It is known that silicon can take up even more lithium than carbon, with a possible capacity of more than 3000 mA-h/g (!).  Complicating matters, Si swells dramatically when taking in Li, meaning that bulk single-crystal Si cracks and self-pulverizes when taken through a few charge/discharge cycles.  However, Si nanowires have been observed to be much better behaved - they have large surface specific surface area, and have enough free surface to swell and shrink without destroying themselves - see here.  Very recently, this paper has spectacular electron micrographs of the swelling of such nanowires.

A second example:  nanostructured cobalt oxide particles, self-assembled using selectively modified virus proteins, have been put forward as high capacity Li ion battery cathodes.  This approach has also been extended to iron phosphate cathode material.

A third example:  dramatically improved charging rates may be possible using nanostructured electrode geometries, such as these inverse-opal shapes.

There is real hope that nanostructured materials may enable true breakthroughs in battery technology, even though batteries have been studied exhaustively for many decades.  The ability to engineer materials at previously inaccessible scales may bear fruit soon.

Rice University clean room manager needed.

Just in case anyone out there has or is a promising candidate, I wanted to point out that Rice University is looking for a new clean room facilities manager.  (This is not a soft money position.)  Here is the text of the advertisement:

Rice University is seeking a technical manager to oversee the operations of its clean room user facility and associated characterization equipment.  This Class 100/1000 facility contains a suite of instruments, including a photolithography mask maker, a contact mask aligner, an e-beam evaporator, an RIE/PECVD system, and a collection of characterization tools.  The manager’s responsibilities include oversight of this facility, training of undergraduate and graduate students and other users, and maintenance and upkeep of the equipment.  Applicants must have a BS degree in a science or engineering discipline (PhD preferred but not required), and extensive experience with several of the relevant instruments or a related technical degree or diploma with an additional 2 years of the related experience (for a total of 7 years of related experience working with clean room instruments).  Salary will commensurate with experience.  The need to fill this position is immediate, and resumes will be examined as they arrive.  Please visit http://cohesion.rice.edu/campusservices/humanresources/riceworks.cfm to apply for this listing.  Rice University is an equal opportunity, affirmative action employer.

A university selling its soul

I'll get back to physics shortly.  These two articles (here and here) explain how, in exchange for $1.5M in donations, the Florida State economics department agreed to give the donors veto power over faculty hiring for the donor-supported positions.  Moreover, the donors can withdraw the positions if they aren't happy with annual performance reviews of the professors.  Wow.  I know times are tight, but FSU has clearly decided that they're up for bid.  I don't care whether the donors are right-wing or left-wing (hint:  they're right wing) or centerist - a university that allows donors direct control over faculty hiring and evaluation is out of its mind.  Gee, you think those professors are going to be free to do whatever research they want?  Do you think there's going to be pressure on all of the faculty within the department to toe the line rather than risk angering the donors?  What a mess.  Well, at least it confirms that Texas doesn't have a monopoly on idiocy.

Update:  blogger ate this post, and I had to reconstitute it from the cached version on bing (google blew this one all the way around).  Clearly the Koch brothers are responsible :-)

Gravity Probe B

Finally, after only 45 years from conception to publication of results, Gravity Probe B has announced (dramatic pause) that Einstein's General Theory of Relativity is consistent with their data.  I had mentioned GPB ("The Project that Ate Stanford") once before.  It was a fascinating, complex, multidisciplinary project that, thanks to its experimental design and extraordinarily long duration, had great impact on a large number of physics, materials science, and engineering careers.  Still, I think they were in a bit of a no-win scenario, particularly once it became clear that there were problems with interpreting the data.  Either they support general relativity, or people just wouldn't trust the results, given how much other evidence there is out there that GR is right, at least in the relatively weak field limit.

Nano for solar

Sorry about the delay in this posting.  Real life has been busy.

Solar energy is an obvious candidate for a long-term solution to many of our energy problems.  The amount of power reaching the surface of the earth is on the order of 350 W/m².  We could meet the world's projected energy needs in 2030 by covering around 250 km by 250 km with 10% efficient solar cells.  Unfortunately, the total surface area of all photovoltaics ever manufactured is less than 0.1% of that.  (This is why being able to produce photovoltaic cells by printing processes would be great.  Hint:  estimate the total area printed by the New York Times in a month.)  There are a number of challenges involved in solar.  Why might "nano" broadly defined be a big help?  Let me give three examples from the large wealth of ideas out there.

1) Semiconductor nanocrystals as absorbers.  Because of the beauty of quantum confinement, it is possible to make semiconductor nanocrystals out of a single material, and use different sizes to capture different parts of the solar spectrum.  Moreover, there is evidence (after some controversy) that nanocrystals may enhance "multiexciton generation" (e.g., here and here).  In a traditional solar cell, a photon with energy twice as large as the semiconductor band gap will generate an electron-hole pair (which must be ripped apart somehow), and inelastic processes will lead to the excess (above the band gap) energy being lost as heat.  However, at some rate, instead you can generate two band-gap-energy pairs.  The idea is that the rate of that process can be enhanced in nanocrystals, since conservation of "crystal momentum" can be relaxed in materials that are so surface-dominated.

2) Nanostructured materials for photoelectrochemical cells.  There are a number of proposals for using electrolytes in solar applications, including dye-sensitized solar cells.  In this case, one would like to use a high surface area anode, such as nanostructured TiO2 or some similar nanostructured material.  Moreover, instead of using organic dyes as the absorbers and sources of photoexcited electrons, one could imagine again using semiconductor nanocrystals.

3) Plasmon-enhanced photovoltaics.  One way to try to boost the efficiency of solar cells is to get the light to hang around the absorber material for longer.  One compact way to do so is to use plasmonically active metal nanoparticles or nanostructures as optical antennas.  The local fields near these structures can enhance scattering and local intensity in ways that tend to boost performance, though resistive losses in the metal may limit their effectiveness.  It's worth pointing out that one can also use plasmonic antennas as sources of hot electrons, also interesting from the photovoltaic angle.

There are many more ideas out there - I haven't even mentioned anything about nanotubes or graphene.  While the odds of any individual idea being a truly transformative breakthrough are small, there are probably more clever things being proposed in this area now that at any time ever before, thanks to our ability to manipulate matter on very small scales.   

Nano and energy

It might be fun to do a few posts on how nanoscale science can be used to the benefit of our energy concerns.  First, let me specify what I mean when I say that there's an "energy problem".  The fact is, average people enjoying first-world standards of living (e.g., US/Canada/Western Europe/Japan) have an enormous per capita energy consumption compared to, e.g., tribesmen in sub-Saharan Africa, or rural farmers in the hinterland of China.  If the goal is to raise the standard of living of the 5-ish billion people not enjoying the high life, and to get everyone up to a high standard of living, then we've got a problem:  there's no nice way to do so without incurring other enormous costs (e.g., burning enormous quantities of fossil fuels; building GW-scale power plants at very high rates, like several per day for the next 30 years).  Either we're not going to raise that standard of living for those billions of people, or the energy costs for the top economic tier are going to have to fall, or we're headed for major upheaval (or possibly some of all of the above).

When I teach my second-semester nano class, I point this out, and if you want interesting quantitative references, check here.  Broadly construed, nanotechnology and nanoscale science (and more broadly, condensed matter physics and materials science) can try to address several aspects of this challenge, though there are certainly no silver bullets.  The areas that come to mind are:  energy generation; energy storage; energy distribution; conservation or improved efficiency; and environmental remediation.  In future posts, I'll try to summarize very briefly a few thoughts on this.   

Public funding of science, and access to information

On multiple blogs over the last few months, I've read comments from lay-persons (that is, nonscientists) that say, in essence, "As a citizen, I paid for this research, and therefore I should have access to all the data and all the software necessary to analyze that data."  The implications are (1) research funded by the public should be publicly accessible; and (2) the researchers themselves sometimes/often? hold back information or misinterpret the results, perhaps because they are biased and have an agenda to further.  

Now, as a pragmatist, there are a number of issues here.  For example, making available raw columns of tab-delimited numerical data and, e.g., matlab code, won't give a nonscientist the technical know-how to do analysis properly, or to know what models to apply, etc.  Things really get tricky if the "data" consists of physical samples (e.g., soil, or ice cores, or zebrafish)....  Yes, scientists that are publicly funded have the responsibility to make their research results available to the public, and to explain those results and their analysis.  As a practical matter, scientists are not obligated to make any interested citizen into an expert on their research.

While this is an interesting topic, I'd rather discuss a related issue:  How much public funding triggers the need to make something publicly available?  For example, suppose I used NSF funding to buy a coaxial cable for $5 as part of project A.  Then, later on, I use that coax in project B, which is funded at the $100K level by a non-public source.  I don't think any reasonable person would then argue that all of project B's results should become public domain because of 0.005% public support.  When does the obligation kick in?  Just an idle thought on a Saturday morning.

Friction, commensurability, and superlubricity

In the limit of clean surfaces, friction has its origins in the microscopic, chemical interactions at the interface between the two objects in question.  One of the more amazing (to me, anyway) consequences of this is the extremely important role played by commensurability between the surfaces.  Let me explain with an example.  Consider a gold crystal terminated at the (111) surface, and another gold crystal also terminated at the (111) surface.  Now, if those two surfaces are brought into contact, with the right orientation so that they match up as if they were two adjacent layers of atoms inside a larger gold crystal, what will happen?  The answer is, in the absence of adsorbed contaminants, the surfaces will stick.  This is called "cold welding".  In contrast, if you bring together two ultraclean surfaces that are incommensurate, they can slide past each other with essentially no friction.  This is called "superlubricity".  Here are two great examples (pdf of first one; pdf of second one) of this.

In this new paper, Liu et al. are able to do some very cute experiments in this regard, looking at the motion of thin graphite flakes (exfoliated from and) sliding on graphite pedestals.  It's clear from the observations that graphite flakes shifted relative to the underlying graphite substrate can slide essentially frictionlessly over micron scales.  Very neat and elegant, and surprising since there is not any rotation at work here to break commensurability.  This is a very firm reminder that our macroscale physical intuition about materials and their interactions can fail badly at the nanoscale.

Playing chicken with the global economy

I get it - we need to fix the structural problems associated with the US budget.  However, don't these geniuses realize that threatening to default (let alone actually defaulting) on the US sovereign debt will severely undermine the dollar?  It's like they actually want to have hyperinflation, so that they can claim it was all Obama's fault.  Other countries don't have a  "debt ceiling", you know.  Update:  seems I'm not alone in realizing that even talking about default is dangerous.

Choosing a postdoctoral position

I had a request a while ago for a post about how to choose a postdoctoral position (from the point of view of a finishing-up grad student, I'm assuming).  This is a tricky topic, precisely because it's somewhere between choosing a grad school (lots of good places to go, with guaranteed open positions every year) and getting a faculty job (many fewer open positions per year in a given field, and therefore a much restricted field of play; plus, a critical need to make some hard decisions that could be postponed or avoided in grad school).  Moreover, different disciplines within the physical sciences have very different approaches on postdocs.  In some fields like astronomy, externally funded fellowships sponsored by observatories/facilities/programs are standard practice, while condensed matter physics is much more principal-investigator-driven.  So, I'll try to stick to general points.

• I strongly suggest going somewhere that is not your graduate institution, unless there are strong extenuating circumstances.  It's just intellectually healthier to get a broad exposure to what is out there, rather than to stay entirely comfortable.
• This is also one of the relatively few points in your career when you can really shift gears, if you are so motivated.  My doctorate was in ultralow temperature physics, but I decided to become a nano researcher, for example.  More dramatically, this is often the point where many people get into interdisciplinary fields like biophysics.  There are trade-offs, of course.  If you do a postdoc in an area very close to your thesis work, you can often make rapid progress.  On the other hand, most people who go on in research (industrial or academic) do not end up working on their thesis topic for the lion's share of their career, and this is a chance to broaden your skill set and knowledge base.
• Word of mouth and self-motivation are essential to getting a good postdoc position, beyond posted ads.  If you're finishing up in grad school, you are enough of a professional that you should be able to email or otherwise contact people whose work you find interesting and exciting, and ask whether they have any postdoctoral openings.  You should make sure that these emails are reasonably detailed and that it's clear they're personalized - not a form letter being spammed to several hundred generic faculty members simultaneously.  Your hit rate won't be high, but it's better than nothing.
• Don't discount industry, though it's a narrowing field.  There are still industrial postdoc positions, and if you've got an interest in industry more so than academia, then you should look at these possibilities.  This includes places like Bell Labs (yes, they still exist), IBM, Intel, HP Labs, etc.  It is a tragedy that there aren't more opportunities like this out there now.
• You need to think about how a particular postdoc position is structured.  Are you going to be acting as middle-management, helping to mentor a team of grad and undergrad students?  Are you going to be leading a research project yourself?  Is there a lot of lab-building or lab-moving?  How long is the position, and how does it match up w/ the seasonal nature of academic hiring, if academia is what you want to do?  Where have previous postdocs in that lab or group ended up?
• How set are you on academia?  If you are set on academia, what kind of academic position would make you happy?  Go into the academic track with your eyes open!  If you're looking beyond academia, what do you need out of a postdoc position (besides a paycheck)?  Are there particular skills you want to learn?

None of this is particularly insightful, but it doesn't hurt to have this written down in one place.  Suggestions for further things to consider are invited in the comments....

Designing a lab

Designing a lab is not trivial, particularly if you have no experience in doing it before.  My new lab (day 2 of the move....) was perhaps the ideal circumstance: a new building is being constructed, and you have a very free hand in determining the layout, the facilities, and so forth.  In any realistic process you never get everything you want (e.g., this building does not have a building-wide deionized water system; I can't have unlimited space; there are restrictions based on cost and feasibility).  The challenge is to end up with functional space - laid out intelligently, so that work flows well and you don't find yourself fighting with the building or yourselves.  Sometimes this is not simple.  In my original lab space, for example, that floor of the building was never designed with vibration-sensitive work in mind.  The need to position certain pieces of equipment on the vibrationally quiet parts of the floor strongly influenced lab layout, rather than basic experimental logic.

Lab design ranges from the Big Picture (e.g., I have a couple of optics tables, so I should probably have a separate area with independently controlled lighting; I want isolation transformers to keep my sensitive measurement electronics off the power lines used for my big pumps.) to a zillion little details (e.g., where should every single electrical outlet and ethernet port be positioned?  What about emergency power?  Gas lines?  What fittings are going to be on the chilled water lines?).  Nothing is ever perfect, and there are always minor glitches (e.g., mislabeled circuit breakers).  You also want to design for the future.  If you think you're eventually going to need a gizmo that requires chilled water or a certain amount of 480V current, it's better to plan ahead, cost permitting....  The situation is definitely more constrained if you're moving into pre-existing space, particularly in an older building.  Like many aspects of being a professor, this is something that no one ever sits down and teaches you.  Rather, you're left to figure it out, hopefully with the help of a professional.

Moving the lab

Today's the beginning of moving my lab into the new Brockman Hall for Physics here at Rice.  As the week goes on, if I have time I'll write a bit about the process of lab design and the joys of moving equipment.  It's exciting, but there's no question that I wish we could skip over the actual transition.

Blogger spam + McEuen novel

Two unrelated topics.  First, blogger needs to get their act together regarding comment spam.  They have some attempt at automatic spam detection, but it's clear that in the last two or three weeks people have figured out how to evade their blocking algorithm.  The spam comments quote some fragment of the original blog post or a previous comment, and then have a clickable username that links to some shady vendor website.  Very annoying.  I'd really rather not shift to a moderated comments approach, but I may have to if this keeps up.

Second, I was very surprised last weekend when reading the Wall Street Journal, and coming upon an article about Paul McEuen (author link, physicist link), who has written apparently a very successful novel.  As one of my friends exclaimed upon hearing this news when I told her at the APS, come on Paul - you're again making the rest of us look like lazy underachievers!  I'm going to have to get this on kindle....

March Meeting, further thoughts

I had to cut my March Meeting a bit short this year, to get back to Rice in time for the dedication of our new Brockman Hall for Physics.  Still, a few more thoughts from the APS meeting:

• Michelle Simmons gave a terrific talk summarizing the work, over more than a decade, of her group at the University of New South Wales on their progress toward their eventual goal of building a quantum computer based on P donors in Si (the Kane approach).  I knew of the work, but I'd never seen it all laid out like that, and it was impressive.  There are very few people out there in the CM community with the fortitude to plan out and pursue steadily a coherent, goal-directed research program over a dozen years.
• I also saw something I hadn't observed in a number of years:  a speaker completely blowing off the 10 minute time limit on a contributed talk.  When the yellow warning light clicked on, it was clear that the speaker was nowhere near the end.  When the red light clicked on and started to blink, still no conclusion.  The session chair stood up and loomed intimidatingly.  No dice.  Finally the speaker ended after a total of about 16 minutes.  That takes nerve (and a lack of consideration for the others in the session....).
• I chaired two sessions this year (note to self:  only chair one session....), and in contrast to the previous point, really didn't have any bad talks at all in there.  Very pleasant, generally.  Most interestingly, the metal-insulator transition in vanadium oxide session was 100% experimental talks!  Perhaps theorists have given up?  (kidding.)  

2011 APS March Meeting, first thoughts

A few brief thoughts at the APS March Meeting (more later....) in Dallas:

• First time I've ever been at a convention center with a graveyard adjacent to the building.  Quite a time saver if there are really bad talks, I suppose.
• Frank Wilczek still gives a terrific talk about the connection between superconductivity and high energy physics.  Very droll, too.  He clearly has a strong aesthetic desire for supersymmetry, but just as clearly acknowledges that all of this could go up in smoke, depending on what the LHC finds.
• The APS's attempt at a mobile app (for iPad, iPhone, etc.) is so painfully slow and incomplete (no scheduling ability I can almost understand, but how can you not list the room numbers for the sessions?) that it's better to use wireless internet access to visit the APS meeting website instead.
• Roland Wiesendanger also presents an outstanding talk.  His group's accumulated work on spin-polarized STM is very impressive, and definitely made me feel an intense bout of "imaging envy" (in the sense that my group's work usually does not have beautiful 3d renders of data sets that grace the cover of glossy journals).
• Lots of discussions with people about looming budget concerns, and separately the decline of science journalism.  On some level, these topics are related....