What’s In a Name?

On Monday, I lectured about the strong nuclear force. It’s called that because it’s, well, a force, that acts within the nucleus of the atom, and is, um, strong.

On Wednesday, I’m lecturing about quarks, which are called that because, um, well, because Murray Gell-Mann is a pretentious git, and wanted to show off the fact that he’d read Joyce.

These pretty much span the full range of names in physics, which are either incredibly dull, or painfully dorky. Physicists have many talents, but coming up with good names for things isn’t one of them.

The worst offenders, in terms of sheer numbers, are probably the particle physicists, but that’s because they have so damn many things to name that they might as well be botanists. After the fifteenth different mystery particle, I imagine you start to get a little punchy. The whole spectrum is really there to see in the Standard Model, with the first generation of quarks having boring names (“up” and “down”), while the second get dorky names (“strange” and “charm”). I’m a little disappointed that they chickened out on using “truth” and “beauty” for the third generation– once you have “strange” and “charm” on the books, why not go to eleven. Instead, we got stuck with the incredibly boring “top” and “bottom,” more’s the pity.

Astrophysics is also a target-rich environment for silly names. Here, though, many of them seem to have been given in scorn, but adopted in pride– “Big Bang” is an excellent example. The name was originally a derisive term coined by Fred Hoyle, but it stuck, and now people use it with a perfectly straight face. Worse yet, I’ve seen otherwise serious talks use “gnaB giB” to refer to the possible collapse of the universe back to a singularity. That ought to be a hanging offense, but in a world where dark matter candidates are divided into “WIMP’s” and “MACHO’s” (for “Weakly Interacting Massive Particles” and “MAssive Compact Halo Objects”– excessively cutesy acronyms are another blight on the field), it barely rates a mention.

Of course, my own field of quantum optics/ atomic physics has perpetrated what might be the worst offense of nomenclature in all of science. It takes a bit of explaining, though: in quantum theory, you often talk about “expectation values,” which are roughly like average values of observable quantities. You represent the expectation value using angle brackets, like so:

< O > = ∫ Ψ* O Ψ

where Ψ is the wavefunction for the system of interest, Ψ* is the complex conjugate of the wavefunction, and O represents the operator of interest. You integrate the right-hand side of that equation over all space to get a numerical value for the expectation value.

There’s another form of notation used in quantum optics circles, though, in which you represent the wavefunction and its conjugate as state vectors. The normal wavefunction is:

| Ψ >

while the complex conjugate is:

< Ψ |

In this scheme, the former is called a “ket,” and the latter a “bra,” and when you put them together to make an expectation value:

< O > = < Ψ | O | Ψ >

you get a bracket.

Just shoot me now.

Comments

  1. #1 Jamie Bowden
    March 7, 2007

    BANG!

  2. #2 Alexi
    March 7, 2007

    C’mon, Murray’s not pretentious.

    Well, even if he is, he’s still entertaining.

    Teacher With A Bad Attitude

  3. #3 Perry
    March 7, 2007

    as a humorist, Dirac was a painful failure……

  4. #4 NJ
    March 7, 2007

    …you get a bracket.

    OK, so which one advances to the next round? Will the normal wavefunction make it to the Final Four?

    March Quantum Madness

  5. #5 DaleP
    March 7, 2007

    Please give credit to Paul Dirac for the bra and ket terms. He split a word (from the term ‘Poisson bracket’ of classical mechanics) long before splitting atoms became popular. I think he uses the terms in his 1930 book Principles of Quantum Mechanics, though I don’t have a copy to check.

  6. #6 Pam
    March 7, 2007

    we got stuck with the incredibly boring “top” and “bottom,”

    Boring?

    Your physicist colleagues are clearly less juvenile than mine.

  7. #7 Blake Stacey
    March 7, 2007

    So quickly they’ve forgotten the Horrendous Space Kablooie.

  8. #8 yagwara
    March 7, 2007

    I agree on the painful physics jokes and cutesy terminology.

    What is sort of charming about “bra” and “ket”, though, is that not only it is a joke by Dirac, but it is generally agreed to be the only joke by Dirac.

  9. #9 Jonathan Vos Post
    March 7, 2007

    “… generally agreed to be the only joke by Dirac.”

    There is an infinite Dirac sea of unfunny things. Only when struck by a sufficently energetic gamma ray does one of the virtual jokes pop into human-detectable existence by pair production of joke-antijoke particles. “Bra” and “Ket” are a hole, a bubble, in that Dirac sea.

    It has been suggested that the jokes and antijokes can have spin either a multiple of hbar/2 or hbar. Thus we have Bozons and Funions.

  10. #10 Louise
    March 7, 2007

    “Dark energy” must be one of the worst names. It sounds evil and probably copyrighted by George Lucas. It hasn’t caught on outside an elite circle of scientists, and never will.

  11. #11 NJ
    March 7, 2007

    It has been suggested that the jokes and antijokes can have spin either a multiple of hbar/2 or hbar. Thus we have Bozons and Funions.

    Then, by placing a series of individual jokes into a very cold room (tough audience), we should be able to condense them into one single Bose-Einstein joke. Obviously, no one could actually hear the joke then, because that would collapse the wavefunction, causing a detectable amount of pie to be thrown into someone’s face.

  12. #12 Upstate NY
    March 7, 2007

    “Bra” and “ket” is fantastic terminology! It inherently helps you remember which goes on the left and right, since bras and kets are different things. The angled bracket notation is nifty too. Did Dirac actually think this was funny? Cute, perhaps, but entirely useful and appropriate. Dirac notation helps you do quantum mechanics.

    I thought Chad was going to rail on “expectation value”, which is entirely confusing, since the expectation value of some operator may be some value you would never observe. Think of position in a 1D harmonic oscillator, evaluated for the n=1 (first excited) energy eigenstate. The “expectation value” is zero, but the wavefunction has a node there. Better to just call it “average”.

  13. #13 Peter Erwin
    March 7, 2007

    Umm… so, what’s your point, beyond “I, personally, think these names suck”?

    Physicists shouldn’t be well-read and educated in other realms of human endeavor, or at least shouldn’t admit it publically? (Shame on you, Gell-Mann, you’re making some of us look bad!) I don’t think that’s what you really thing, but it’s an implication I get from what you said.

    The other problem with an Andy-Rooney-ish rant like this is you don’t give any examples of good names, only bad ones. I’m mildly curious as to your criteria for good names in physics.

  14. #14 anonymous
    March 7, 2007

    I submit that “gluon” is the perfect balance of dull and dorky.

  15. #15 Jonathan Vos Post
    March 7, 2007

    “… one single Bose-Einstein joke…”

    So Bose, Einstein, Fermi, and Dirac walk into this bar.

    [middle of joke to be done]

    “Of course not,” said the bartender, throwing them out the door. “This is an h-bar!”

    [ducks cryogenic pie or pi]

  16. #16 D
    March 7, 2007

    you think top and bottom are boring? If there’s a fourth generation, I’m shooting for dom and sub.

  17. #17 Julianne
    March 7, 2007

    One of my favorite things about the physics-astronomy building at UW is the cafe on the ground floor, named the h-bar.

    Peter — it’s probably hard to quibble with names like “neutron”, “proton”, and “electron”. They all convey useful information about their properties without being too cutesy. However, I still like “quark” and its flavors, so I’m not a tough crowd.

  18. #18 Babbler
    March 7, 2007

    “Dark energy” must be one of the worst names. It sounds evil and probably copyrighted by George Lucas. It hasn’t caught on outside an elite circle of scientists, and never will.

    Don’t forget the dark MATTER and dark ENERGY are two different thing entirely.

  19. #19 Bob Hawkins
    March 7, 2007

    Actually, the largest category of physics names is “misleading.” “Relativity” has its invariants, the “speed of light” is the speed of lots of other things, nothing rotates in “isotopic spin,” no one is shocked by “anomalous dispersion,” and don’t even get started on centrifugal, centripetal and Coriolis “forces.”

  20. #20 Eric Lund
    March 7, 2007

    in a world where dark matter candidates are divided into “WIMP’s” and “MACHO’s” (for “Weakly Interacting Massive Particles” and “MAssive Compact Halo Objects”– excessively cutesy acronyms are another blight on the field)

    As a space scientist, I resemble that remark.

    A handful of acronyms from space flight hardware projects:
    FAST (Fast Auroral SnapshoT)
    ACE (Advanced Composition Explorer)
    STEREO (Solar TErrestrial RElations Observatory)
    TIMED (Thermosphere Ionosphere Mesosphere ElectroDynamics)
    TWINS (I don’t remember what this one stands for, but there are two spacecraft involved)
    ..and there are plenty more where those came from.

    But the all-time worst acronym was a (thankfully) now obsolete computer database system NASA used for scientific proposals. It was actually called SYS-EYFUS, the last five letters being the mail codes for the major scientific divisions before the O’Keefe reorg in 2004. Those of you who remember Greek mythology might note the resemblance to the soft money lifestyle.

  21. #21 Baratos
    March 7, 2007

    The worst acronym has to go to “The Committee for the Liberation and Integration of Terrifying Organisms and their Rehabilitation Into Society”, aka “CLITORIS.”

    Fictional space explorers beat physicists at bad acronyms hands-down.

  22. #22 Ben L
    March 8, 2007

    The funny thing about acronyms is that people often go through many contortions to get it to come out right. e.g. ATLAS, the “Large Toroidal LHC ApparatuS”, or PHENIX, the “Pioneering High Energy Nuclear Interaction eXperiment” which manages to both use a letter from the wrong place and come out misspelled.

  23. #23 Eric
    March 8, 2007

    I find it interesting that you talk about Dirac’s bra/ket notation as a specifically atomic physics thing. I don’t think I’ve met a physicist who doesn’t use it, and it’s been standard notation in my courses since undergrad QM.

    @Julianne: The h-bar is indeed a splendidly named establishment, but the chuckles derived from the name seem to wane in inverse proportion to the amount of money one spends there.

    And as for nomenclature, I was rather amused when I first learned that standard practice for naming supersymmetric partners to known fermions was simply to add an s to the beginning of the name. My wife has expressed interest in one day having a dog named “Squark”.

  24. #24 Jonathan
    March 8, 2007

    No mention of “Very Large …” for astronomical systems? I find it personally embarrassing to tell someone yes, that IS it’s name.

  25. #25 CET
    March 8, 2007

    It could be worse.

    Organic chemists have a standardized system for naming molecules. But it’s so convoluted that no one (including chemical suppliers) uses it.

    Then there are Biochemists, who do horrible things like naming one of the proteins involved in fertilization ‘penetratin’ or naming a common quinone-derived biomolecle ‘ubiquinone.’

    Or (shudder) geneticists. I knew someone who did drosophila work for his Phd. When his lab discovered genes whose failure caused the flies to behave nonsensically, they named them after grad students in a rival group.

  26. #26 micro mel
    March 8, 2007

    @ CET-
    “Or (shudder) geneticists. I knew someone who did drosophila work for his Phd. When his lab discovered genes whose failure caused the flies to behave nonsensically, they named them after grad students in a rival group.”

    Haha. Awesome! :)

  27. #27 Peter Erwin
    March 8, 2007

    Like Julianne, I happen to like “quark” and the associated flavor terminology; I think it makes for an amusing contrast to the standard Greco-Latinate -on system, and I think literary references are a fine idea. The organic-chemist system that CET mentions is maybe a warning of what happens when you get too obsessed with keeping everything “dignified” and pseudo-Classical. (Not to mention that the “-on” suffix is by now hopelessly generic and even parodic; just look at all the fake particles in Star Trek.)

    I do agree that the convoluted acronym approach that dominates instruments is pretty silly (telescope instrumentation is as bad as space science in this regard: SINFONI, DOLORES, ISAAC, SOFI [= Son of ISAAC], FLAMES, FLAMINGOS). Perhaps we should adopt the military system of generating random combinations of words for new projects, like “Have Blue” (which was the code name for the Stealth Fighter prototype).

    No mention of “Very Large …” for astronomical systems? I find it personally embarrassing to tell someone yes, that IS it’s name.

    Well, now there are ELT (Extremely Large Telescope) projects, and a group in Europe was trying to go one better by pushing OWL (Overwhelmingly Large [Telescope]). Sometimes I think the next giant telescope project should just be named BFT. (That’s a Doom reference, by the way.)

  28. #28 Chad Orzel
    March 8, 2007

    The funny thing about acronyms is that people often go through many contortions to get it to come out right. e.g. ATLAS, the “Large Toroidal LHC ApparatuS”, or PHENIX, the “Pioneering High Energy Nuclear Interaction eXperiment” which manages to both use a letter from the wrong place and come out misspelled.

    My favorite along those lines is “LENS,” which Bill Phillips pointed out stands for “Laboratoire European du Non-linear Spectroscopy,” changing languages halfway through in order to get the acronym right.

    A post-doc when I was in grad school was pushing “UBOAT” for “Ultra-Blue Optical Atom Trap.” It’s probably a good thing that it never worked…

  29. #29 raj
    March 8, 2007

    Speaking as a semi-layman, I do get a kick out of the names that physicists have given to the six flavors of quarks. Especially the “charm” quark.

  30. #30 patrick
    March 8, 2007

    “Then there are Biochemists, who do horrible things like naming one of the proteins involved in fertilization ‘penetratin’ or naming a common quinone-derived biomolecle ‘ubiquinone.’
    Or (shudder) geneticists. ”

    My recent favorite is reading a blurb in Science (here)
    about an inhibitor called Dickkopf-1. There’s a word I never
    expected to read in Science. I can understand why they abbreviated it to DKK-1.

  31. #31 Jonathan Vos Post
    March 8, 2007

    Feedback
    * 18 December 2004
    * NewScientist.com news service

    Non-sciency names

    WE recently reported Steve Hibbert’s proposition that “prion” is a sciency name while “spongler” is not (27 November). Did readers know of any other non-sciency names that have squinked into the lexicon, we wondered.

    A gratifying large number did, and here are some of the examples that were sent in. Many come from the computer industry, including nybble (half a byte), Kermit transfer protocol, dongle, snort, Twain (“thing without an interesting name”), incredible woz machine (part of an Apple Mac) and flops.

    From biology we have the hunchback gene and the sonic hedgehog, desert hedgehog, tiggy-winkle hedgehog and Indian hedgehog genes.

    Chemistry brings us buckminsterfullerene, cummingtonite, moronic acid, unununium, curious chloride and a host of other names listed on http://www.chm.bris.ac.uk/sillymolecules/sillymols.htm.

    And then from maths we have penguin diagram, googol (10100), strange attractor, and emirp, emirpimes and iccanobif (Jonathan Vos Post, the inventor of emirpimes, explains that you can see where these come from by reversing the letters).

    Finally, physics offers the barn (“the effective cross-sectional area of a target nucleus”, Daniel Large tells us), beam dumps and wigglers (used routinely at the Daresbury Synchrotron light source in the UK, says Jonathan Knowles), and last but not least, quarks and gluons and the strangeness and charm that quarks are reputed to possess.

    Thanks to all who sent in these examples. But before we leave this topic, a message from Alec Cawley to anyone with the opportunity of minting new scientific names. He says there are said to be four words in the English language for which there are no rhymes: silver, purple, orange and month.

    If your newly coined word provides such a rhyme, not only will you be doing poets a favour, but also your coinage is more likely to be celebrated in verse – albeit (probably) doggerel.

  32. #32 Peter Erwin
    March 8, 2007

    Fun that biologists have had naming things:
    Curious Scientific Names

    Including:
    Bambiraptor (a dinosaur), Dalailama (a moth), Darthvaderum (a mite), Gollum (a shark), Antimargarita (a snail), Ichabodcraniosaurus (a dinosaur that was, yes, found missing its head), and on and on…

  33. #33 CET
    March 8, 2007

    Re: #31

    I would one to the chemistry list: ‘Magic Methyl.’ A name that aptly describes its ability to methylate molecules and researchers.

  34. #34 David Phillips
    March 9, 2007

    Scientific American ran a brief profile of / interview with Murry Gell-mann about a decade ago. (I didn’t look to see if it was online.) The interviewer observerd that Gell-mann was accused by people of being a know-it-all. Gell-mann’s response? “Well, I do know a lot of things.”

  35. #35 Jonathan Vos Post
    March 9, 2007

    I like Murray Gell-mann very much. It was fun watching him spar with Feynman for the role of Alpha Nobel Physics Dude. When Feynman hit bestsellerdom with “Surely You’re Joking, Mr.Feynman” — Murray went to his agent and demanded a $1 million advance royalty book deal for his (yet to be written) autobiography. [curiously parallel, to the dollar, with the Rolling Stones being the first rock group in the world to get $1,000,000 in advance for an unrecorded album, when the Beatles got about half that].

    The agent pointed out the importance of a title in pitching to a publisher. The Feynman book was named from a phrase actually spoken to Feynman.

    “Can you give me an example from you’re life of something that people often say to you?”

    Murray Gell-mann smiled, and said:

    “Damn It, You’re Right Again, Murray.”

    The book was retitled “The Quark and the Jaguar.”

    And he did get $1,000,000 in advance.

  36. #36 ColoRambler
    March 9, 2007

    I do agree that the convoluted acronym approach that dominates instruments is pretty silly…

    You think that’s bad, try NMR spectroscopy. The madness probably started with INEPT (a polarization transfer experiment) and progressed from there. 10-15 years ago NMR spectroscopists joked that you couldn’t publish a new technique without inventing a semi-stupid acronym for it. OK, folks, I know you don’t feel very SECSY, and maybe you feel totally INADEQUATE, but that’s a bit much.

  37. #37 Luke
    March 9, 2007

    The boojum rules – and in David Mermin’s words, Russian now sports the spectacular instrumental plural (budzhumami).

  38. #38 Akhila Raman
    March 10, 2007

    Often i wonder if Einstein may have been right in his assessment of Quantum mechanics(QM) that it is okay as a mathematical model which explains observations in the quantum realm, but there may be a larger theory which subsumes QM and removes the uncertainty at the heart of it.

    What bothers me about QM is this rather religious belief
    in the postulate that “mathematics = physics”. The notion
    that if theorists are able to come up with a set of equations- consistent and elegant and fit observations
    in a finite set of points, then it must be “true”.
    That if mathematics requires 11-dimensions, then universe also should have 11 dimensions.
    [ http://www.pbs.org/wgbh/nova/elegant/view-witten.html ] Never mind the fact that mathematics uses infinitesimal calculus which requires infinite number of points to observe(as dx->0, Number of points->infinity) to make any “exact” statement about Nature.

    In this context, the chapter “Is Nature Unreasonably Mathematical?” in Sudarshan and Rothman’s 1998 book
    “Doubt and Uncertainty” is worth revisiting.

    -Akhila Raman

  39. #39 morinao
    March 11, 2007

    Or (shudder) geneticists. I knew someone who did drosophila work for his Phd. When his lab discovered genes whose failure caused the flies to behave nonsensically, they named them after grad students in a rival group.

    Can’t talk about frivolous Drosophila geneticists without mentioning the Sonic hedgehog gene. First they found a gene whose mutation causes fruit-fly embryos to develop spiky projections, and naturally named the gene “hedgehog”. Then they systematically named the mammalian homologues after hedgehog species: “desert hedgehog”, “Indian hedgehog”, etc. Then some wiseass named one after the cartoon hedgehog in a Sega video game. Guess which one turned out to be the key to neural development and certain types of cancer formation?

    Doctors hate this name because no one likes to tell a kid, “Your cancer was caused by Sonic hedgehog.”

  40. #40 morinao
    March 11, 2007

    and speaking of bad acronyms, how about POK Erythroid Myeloid ONtogenic factor, an oncogene whose name had to be changed after Nintendo threatened to sue because news organizations were running headlines saying, “POKEMON causes cancer”.