This week I am attending the every-two-years DOE Experimental Condensed Matter Physics PI meeting.  Previously I have written up highlights of these meetings (see here, here, here, here, here), though two years I was unable to do so because I was attending virtually.  I will do my best to hit some high points (though I will restrict myself to talking only about already published work, to avoid any issues of confidentiality).   In the meantime, here are a couple of topics of interest from the last couple of weeks.   I just learned about the existence of Mathos AI, an AI product that can function as a math solver and calculator, as well as a tutor for students.  It is pretty impressive. I liked this historical piece about Subrahmanyan Chandrasekhar (he of the “Chandrasekhar limit”, which describes the degeneracy physics + gravitation that limits the upper size of compact stellar objects like white dwarfs and neutron stars before they collapse into black holes) and his interactions with Stephen Hawking.  It's pretty humanizing to see an intellectual giant like Chandra sending a brief letter to Hawking in 1967 asking for advice on what to read so that Chandra can understand Hawking’s work on singularities in cosmology.  Hawking’s handwritten response is clear and direct. In an online discussion about what people will do if Google decides to stop supporting Google Scholar, I was introduced to OpenAlex.  This seems like an interesting, also-free alternative.  Certainly worth watching.  There is no obvious reason to think that Google Scholar is going away, but Alphabet has retired many free products, and it’s far from obvious how they are making any money on this.  Anyone from Google who reads the blog, please chime in.  (Note to self:  keep regularly backing up this blog, since blogger is also not guaranteed future existence.)

Back in the dawn of the 21st century, the American Chemical Society founded a new journal, Nano Letters, to feature letters-length papers about nanoscience and nanotechnology.  This was coincident with the launch of the National Nanotechnology Initiative, and it was back before several other publishers put out their own nano-focused journals.  For a couple of years now I've been an associate editor at NL, and it was a lot of fun to work with my fellow editors on putting together this roadmap, intended to give a snapshot of what we think the next quarter century might hold.  I think some of my readers will get a kick out of it.

The fall semester is about to begin at my university, and I'm going to be teaching undergraduate statistical and thermal physics.  This is a course I've taught before, last full term in 2019, and the mass availability of large language models and generative AI tools have changed the world in the interim.  We've all seen the headlines and articles about how some of these systems can be very good at solving traditional homework and exam problems.  Many of these tools are capable of summarizing written material and writing essays that are very readable.  Higher education is wrestling with the essential question:  What is the right working relationship between students, teachers, and these tools, one that benefits and actually educates students (both about subject matter and the use of these tools)?  Personalized individual AI tutoring seems like it could be great for teaching huge numbers of people.  Conversely, if all we are doing is teaching students to copy-paste assignments into the homework-answer-machine, clearly we are failing students at multiple levels.   The quote in the image here (from Kathy Hepinstall Parks) is one that I came across this week that originates in the FAQ from a writers workshop.  For my purposes I could paraphrase:  Why should we learn physics (or any other science or engineering discipline) when a machine already knows the formalism and the answers?  On some level, this has been a serious question since the real advent of search engines.  The sum total of human knowledge is available at a few keystrokes.  Teaching students just rote recall of facts is approaching pointless (though proficiency can be hugely important in some circumstances - I want a doctor who can diagnose and treat ailments without having to google a list of my symptoms.). My answer to this question is layered.  First, I would argue that beyond factual content we are teaching students how to think and reason.  This is and I believe will remain important, even in an era when AI tools are more capable and reliable than at present.  I like to think that there is some net good in training your brain to work hard, to reason your way through complicated problems (in the case of physics, formulating and then solving and testing models of reality).  It's hard for me to believe that this is poor long-term strategy.  Second, while maybe not as evocative as the way creative expression is described in the quote, there is real accomplishment (in your soul?) in actually learning something yourself.  A huge number of people are better at playing music than I am, but that doesn't mean it wasn't worthwhile to me to play the trumpet growing up.  Overworked as referencing Feynman is, the pleasure of finding things out is real.   AI/LLMs can be great tools for teachers.  There are several applet-style demos that I've put off making for years because of how long it would take for me to code them up nicely.  With these modern capabilities, I've been able to make some of these now, in far less time than it would otherwise have taken, and students will get the chance to play with them.  Still, the creativity involved in what demos to make and how they should look and act was mine, based on knowledge and experience.  People still have a lot to bring to the process, and I don't think that's going to change for a very long time.

Amazingly, this blog has now been around for more than twenty years (!) - see this first post for reference from June of 2005, when I had much less gray hair and there were a lot more science blogs.  Thanks to all of you for sticking around. Back then, when I debuted my writing to my loyal readers (all five of them at the time), I never thought I'd keep this up.  Some info, including stats according to blogger: Total views: 8.3M Most views in one day, this past May 31, with 272K Top two most-viewed posts are this one from 2023 with a comment thread about Ranga Dias, and this one from 2009 titled "What is a plasmon?" Just a reminder that I have collected a bunch of condensed matter terms and concept posts here. I've also written some career-related posts, like a guide to faculty job searches, advice on choosing a graduate school, needs-to-be-updated advice on postdoc positions, etc. Some personal favorite posts, some of which I wish had gotten more notice, include the physics of drying your hands, the physics of why whiskey stones aren't as good as ice to cool your drink, materials and condensed matter in science fiction, the physics of vibranium, the physics of beskar, the physics of ornithopters, and why curving your pizza slice keeps if from flopping over.  I'm also happy with why soft matter is hard, which was a well-viewed post. I also like to point out my essay about J. Henrik Schön, because I worry that people have forgotten about that episode. Real life has intruded quite a bit into my writing time the last couple of years, but I hope to keep doing this for a while longer.  I also still hope one day to find the right time and approach to write a popular book about the physics of materials, why they are amazing, and why our understanding of this physics, limited as it is, is still an astonishing intellectual achievement.  Two other things to read that I came across this week: This post about Maxwell's Demon from the Skull in the Stars blog (which has been around nearly as long as mine!) is an excellent and informative piece of writing.  I'm definitely pointing my statistical and thermal physics undergraduate class to this next month. Ross McKenzie has a very nice looking review article up on the arXiv about emergence. I haven't read it yet, but I have no doubt that it will be well-written and thought-provoking.

It's been a busy time that has cut into my blogging, but I wanted to point out some links from the past couple of weeks. Physics Today has a cover article this past issue about what is colloquially known as static electricity, but what is more technically described as triboelectricity, the transfer of charge between materials by rubbing.  I just wrote about this six months ago, and the detailed mechanisms remain poorly understood.  Large surface charge densities (like \(10^{12}\) electronic charges per square cm) can be created this way on insulators, leading to potential differences large enough to jump a spark from your finger to the door handle.  This can also lead to static electric fields near surfaces that are not small and can reveal local variations in material properties. That leads right into this paper (which I learned about from here) about the extreme shapes of the heads of a family of insects called treehoppers.  These little crawlies have head and body shapes that often have cuspy, pointy bits that stick out - spines, horns, etc.  As we learn early on about electrostatics, elongated and pointy shapes tend to lead to large local electric fields and field gradients.  The argument of this paper is that the spiky body and cranial morphology can help these insects better sense electric field distributions, and this makes it easier for them to find their way and avoid predators.  This manuscript on the arXiv this week is a particularly nice, pedagogical review article (formatted for Rev Mod Phys) about quantum geometry and Berry curvature in condensed matter systems.  I haven't had the chance to read it through, but I think this will end up being very impactful and a true resource for students to learn about these topics. Another very pretty recent preprint is this one, which examines the electronic phase diagram of twisted bilayers of WSe2, with a relative twist angle of 4.6°.  Much attention has been paid to the idea that moiré lattices can be in a regime seemingly well described by a Hubbard-like model, with an on-site Coulomb repulsion energy \(U\) and an electronic bandwidth \(W\).  This paper shows an exceptionally clean example of this, where disorder seems to be very weak, electron temperatures are quite cold, and phase diagrams are revealed that look remarkably like the phenomena seen in the cuprate superconductors (superconducting "domes" as a function of charge density adjacent to antiferromagnetic insulating states, and with "strange metal" linear-in-\(T\) resistance in the normal state near the superconducting charge density).  Results like this make me more optimistic about overcoming some of the major challenges in using twisted van der Waals materials as simulators of hard-to-solve hamilitonians. I was all set to post this earlier today, with no awful news for once about science in the US that I felt compelled to discuss, but I got sidetracked by real work.  Then, late this afternoon, this executive order about federal grants was released.   I can't sugar coat it - it's awful.  Ignoring a large volume of inflammatory rhetoric, it contains this gem, for instance:  "The grant review process itself also undermines the interests of American taxpayers."   It essentially tries to bar any new calls for proposals until a new (and problematic) process is put in place at every agency (see Sect. 3(c)).  Also, it says "All else being equal, preference for discretionary awards should be given to institutions with lower indirect cost rates."  Now, indirect cost rates are set by negotiations between institutions and the government.   Places that only do very small volumes of research have low rates, so get ready for MIT to get fewer grants and Slippery Rock University to get more.  The only certainty is that the nation's lawyers are going to have a field day with all the suits that will come out of this.