"Translational symmetry breaking is antagonistic to static fluidity"

« previous post | next post »

This is physics, not surrealist poetry — K Kinjo et al., "Superconducting spin smecticity evidencing the Fulde-Ferrell-Larkin-Ovchinnikov state in Sr2RuO4", Science 4/21/2022:

Translational symmetry breaking is antagonistic to static fluidity but can be realized in superconductors, which host a quantum-mechanical coherent fluid formed by electron pairs. A peculiar example of such a state is the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state, induced by a time-reversal symmetry–breaking magnetic field applied to spin-singlet superconductors. This state is intrinsically accompanied by the superconducting spin smecticity, spin density–modulated fluidity with spontaneous translational-symmetry breaking. Detection of such spin smecticity provides unambiguous evidence for the FFLO state, but its observation has been challenging. Here, we report the characteristic “double-horn” nuclear magnetic resonance spectrum in the layered superconductor Sr2RuO4 near its upper critical field, indicating the spatial sinusoidal modulation of spin density that is consistent with superconducting spin smecticity. Our work reveals that Sr2RuO4 provides a versatile platform for studying FFLO physics.

I think I know what "translational symmetry breaking" means. But they lost me at "static fluidity" — and Google just points me at an Australian art installation.

If you were wondering about the "spin smecticity" part, Wiktionary tells us that smecticity is "The quality of being smectic", and smectic in turn is an adjective "describing a class of liquid crystals whose molecules are aligned in layers, with the molecules lying perpendicular to the plane of the layers."

As far as I know, poets have yet to take (either prosodic or conceptual) advantage of smecticity.



  1. Ross Presser said,

    April 28, 2022 @ 11:06 am

    A static fluid is one that is not "moving" with respect to itself, like a glass of water sitting undisturbed on a table; or water moving smoothly through a pipe with absolutely no turbulence (and ignoring the laminar flow — the fact that water adjacent to the pipe experiences friction that water in the center of the pipe does not).

    A non-static fluid is flowing somewhere, or rotating, or turbulent, or in some other state. Wind, a stirred teacup, a gas explosion.

    So "Translational symmetry breaking is antagonistic to static fluidity" means that if translation symmetry is broken – i.e., if the movement of an element of fluid depends on exactly where in the body it is located — then it's usually impossible for the fluid to be static, i.e. there's turbulence or some other self-movement.

    In superconductors, the fluid formed by the paired electrons can be static, i.e. flowing smoothly, despite an irregular shape of the material forming the superconductor.

    That's my slightly-informed-layman take on the first sentence of this abstract.

  2. Alexander Browne said,

    April 28, 2022 @ 12:10 pm

    I feel like a non–linguistics-inclined physicist might have the same reaction to a paper with a dense e.g. phonology or syntax jargon. ("I know 'labio' is related to lips and 'dental' is teeth, and what friction is, but…")

  3. CD said,

    April 28, 2022 @ 1:03 pm

    Your crystalline smecticity
    Evokes a strange complicity

  4. AntC said,

    April 28, 2022 @ 3:05 pm

    FFLO: Did Philip Larkin moonlight as a superconductor researcher?

    Why did he think adding meant increase?
    To me it was dilution.

    but its observation has been challenging.

    I think we should be told.

  5. ohwilleke said,

    April 28, 2022 @ 3:09 pm

    There are far better examples of scientific phrases and sentence structure if you want to look for them.

    For example, there is an ample literature about "light dark matter" (low mass particles that do not interact via electromagnetism).

    Another of my favorite scientific terms is "pretzelosity" sometimes spelled prezelocity" which I discussed at https://dispatchesfromturtleisland.blogspot.com/2015/01/physics-word-of-day-pretzelosity.html which is defined to mean: helicity − transversity = pretzelosity

    Then there is "nuclear pasta" https://en.wikipedia.org/wiki/Nuclear_pasta which is not to be confused with Spaghettification https://en.wikipedia.org/wiki/Spaghettification

    High energy physics also has lots of papers that discuss "penguins" (a typical of physics process described by a diagram that looks like a penguin). https://www.smithsonianmag.com/smart-news/how-a-physics-diagram-was-named-after-a-penguin-1793241/

  6. cameron said,

    April 28, 2022 @ 5:26 pm

    The New York Times used to run a bridge column. I'm sure its contents were entirely unremarkable to anyone who knows even the least little bit about the game of bridge, but to someone like me, who has never indulged in that vice, it was like a little bit of surrealist poetry to read every day.

  7. stephen said,

    April 28, 2022 @ 8:46 pm

    A noted writer in the 19th century had some found poetry in a physics textbook.


    William Whewell was a giant of 19th-century science.
    His Elementary Treatise on Mechanics contains the following poetic sentence:

    And hence no force, however great,
    can stretch a cord, however fine,
    into a horizontal line
    that shall be absolutely straight.

    But Whewell quietly changed the wording in the next edition.

    Here's another book I found long ago:

    The Space Child's Mother Goose.


  8. Robert T McQuaid said,

    April 29, 2022 @ 4:51 am

    When a scientific paper has dozens of authors, it should add one more.
    Someone from the English department, to turn unnecessary jargon into comprehensible language.

  9. Mark P said,

    April 29, 2022 @ 8:03 am

    The language of physics, however dense it might seem to a layman, is comprehensible to the people it’s aimed at. Even simple, “comprehensible” words can mean something different to a physicist than to a layman.

  10. KeithB said,

    April 29, 2022 @ 8:21 am

    Mark P:
    Not just physics. One of the problems with the recent ruling lifting the mask requirements on airplanes was a misunderstanding of the way public health scientists use the word "sanitation".
    (At least that is what NPR said)

  11. V said,

    April 29, 2022 @ 1:52 pm

    Mark: I'm not sure what you're trying to say.

  12. V said,

    April 29, 2022 @ 1:54 pm

    (Mark Liberman), sorry.

  13. Vampyricon said,

    April 30, 2022 @ 9:37 am

    @Robert T McQuaid

    I understood most of that, and I'm not even in condensed matter physics.

  14. astrange said,

    May 1, 2022 @ 12:34 am

    Some strange terms from the world of math(s):


  15. Seth said,

    May 2, 2022 @ 6:18 am

    Every topic has its specialized jargon, which sounds strange to those who don't know it:

    "The Fantastic Mr. Fox:

    Kristofferson: Coach, we don't have whack-bat where I'm from. What are the rules?
    Coach Skip: There's no whack-bat on the other side of the river?
    Kristofferson: No, we mostly just run grass sprints or play acorns.
    Coach Skip: Well, it's real simple. Basically, there's three grabbers, three taggers, five twig runners, and the player at whack-bat. The center tagger lights a pine cone and chucks it over the basket and the player tries to hit the cedar stick off the cross rock. Then the twig runners dash back and forth until the pine cone burns out and the umpire calls "hotbox". Finally, you count up however many score-downs it adds up to and divide that by nine."

  16. Philip Taylor said,

    May 2, 2022 @ 8:21 am

    Hmmm, I can't see whack-bat replacing dwile flonking any time soon …

RSS feed for comments on this post