Also featuring my Ph.D. advisor Randy looking uncharacteristically serious in his role as a visionary editor! #rmp90pic.twitter.com/LPhSX6KVlf
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Also featuring my Ph.D. advisor Randy looking uncharacteristically serious in his role as a visionary editor! #rmp90pic.twitter.com/LPhSX6KVlf
It's probably a good occasion to reflect on the RMP article that's had the greatest influence on me: The topological theory of defects in ordered media, by N. D. Mermin (1979) https://journals.aps.org/rmp/abstract/10.1103/RevModPhys.51.591 …. I remember @takuyakitagawa first showing it to me when we were undegrads!pic.twitter.com/pMzL4Zk6OT
Here's the topic: one way of classifying materials is by their symmetries, e.g. crystals have discrete units repeating in space, but gases and liquids are (after averaging) spatially uniform. These symmetries turn out to determine the defects that can appear, such as dislocationspic.twitter.com/0xryT7Ao4T
(which show up as flaws in diamonds, silicon, and other crystals). This linked tweet shows disclination defects in a nematic liquid crystal https://twitter.com/vancew/status/1004872092678963200 …. Mermin's article explains how all this can be studied using an arcane branch of topology called "homotopy theory"!
It's a very ambitious article: fearlessly guiding physicists into deep waters with few proofs but many pictures and appeals to intuition about strange materials like the aforementioned nematic LCs (famous for their use in displays) and the two flavors of superfluid helium-3.pic.twitter.com/7AaOeVa15P
Many elegant diagrams, which came in handy when I hit the math books later. Here are a few of my favorites: the 2nd homotopy group (pi_2), the Eckmann-Hilton argument, the action of the fundamental group on pi_2, and a truly magnificent sketch of a "commutator" loop!pic.twitter.com/IU4jqJArRW
Long story short, Gareth Alexander, @Sabetta_, Randy and I eventually wrote an RMP article ourselves, with more about how point and loop defects in nematic liquid crystals can interact https://journals.aps.org/rmp/abstract/10.1103/RevModPhys.84.497 … @Sabetta_ did all the illustrations herself! How are these for #SciArt?pic.twitter.com/I2juB4xqYZ
I'm the proud owner of the original "Figure 10" (framed in my old bedroom), which illustrates the pattern on the surface of a sphere (colloid) that you'd see if you submerged it in a liquid of rectangular prisms (biaxial nematic) that want to "point outwards" (radial anchoring)!pic.twitter.com/hJZyYS8CcB
If you made it here, thanks for reading, and I'd love to hear about any review articles or expositions that have had a big impact on your work, in RMP or elsewhere!
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