S03E13: The Bozeman Reaction

My favorite word in physics is Zitterbewegung.  Coming in at close seconds are Bremsstrahlung and Ansatz.  These technical terms, at least for physicists,  mean “rapid oscillation”,  “braking radiation” and “starting point” in German.  (I chose not to even mention Eigenvectorbecause I didn’t want to have to explain it.) However, viewers of tonight’s show saw  Sheldon use the most famous of all German physics words, Gedankenexperiment.    Thanks to Kai of the German BBT fansite “Big Bang Forum” for the audio files.

Like modern physicists, Sid Caesar employed German words.

Today’s modern physics is peppered with German words, a relic of the founding of modern physics in Germany, Austria and Switzerland about 100 years ago.   The German-speaking  heritage of  the giants of late 19th and early 20th century physics is not hard to discern from their names:   Ludwig Boltzmann,  Max Planck,  Albert Einstein, Erwin Shroedinger, Lise Meitner, Otto Stern, Werner Heisenberg, Wolfgang Pauli, James Franck, Max von Laue, …

These masters gave us the concept of a Gedankenexperiment, or a “thought experiment”.   Physics is at its deepest core an experimental science.  Questions that cannot be subject to experimental testing, at least in principle, are outside the realm of physics and are left, at best, to the philosophy department.  Now some experiments are too hard to do as a matter of practice, or  too unsavory.  But even if in principle an experiment could be conducted, the question of its outcome remains squarely in physics.  An experiment you can think about doing, but don’t need to actually perform, is a Gedankenexperiment.  Physicists use Gedankenexperiments for several purposes.   First, they allow teachers to isolate  physical effect perfectly in an explanation for students.  They allow presentation of possible paradoxes and their resolution for pedagogical purposes.   Second, they allow us to see if a set of physical rules are impossible.  If the result of a Gedankenexperiment contradicts the known laws of physics, then at least one of the principles upon which the Gedankenexperiment rests must be flawed.

Sheldon was using Gedankenexperiments for their third purpose, to see if a physics theory has any meaning at all.   If Sheldon has a physics theory, but there is not a single observation that would be different with versus without it, then his theory might as well not even exist.   Physicists are currently grappling with Gedankenexperiments to see if various interpretations of what it means to make a measurement in quantum mechanics (what Sheldon called “the quantum measurement problem”) have any meaning at all.

“I cannot define the real problem, therefore I suspect there’s no real problem, but I’m not sure there’s no real problem.” –Richard Feynman

Gedankenexperiments could someday illustrate if the quantum measurement problem really exists as a physics problem.  In tonight’s episode, Sheldon tells us he had “four out of the five Gedankenexperiments” that he thought would be necessary already written out on his laptop.  Was he close?  After what happened to his laptop, the world may never know.

Several famous Gedankenexperiments of this sort remain:

Shroedinger’s Cat was discussed at the end of Season 1.     In quantum mechanics, particles can exist in multiple observable states at once, in what is called a “superposition”.  To examine the implications further, Schroedinger put a Gedanken-cat (“thought cat”)  in a box and based on whether a certain radioactive atom decayed (or not), a bottle of poison would be opened (or not) and kill the cat (or not).   An experimentalist who has not yet looked in the box would have the treat the cat as a superposition of an alive and dead cat.  Schroedinger originally devised this Gedankenexperiment as a reductio ad absurdem argument.  He intended to show the concept to be ridiculous because, he argued, nothing as large as a cat could exist in a superposition of states.   However, the tables turned on Schroedinger since nothing has ever been done to show that such a state of a cat is impossible.  Instead, this Gedankenexperiment can now be used as an example of how quantum mechanics works.  Even the kitty litter would be both soiled and clean at once.

Einstein’s twin “paradox” was, like the Schroedinger’s cat Gedankenexperiment, developed to show a dramatic consequence of Einstein’s theory of relativity, but is only mislabeled as a paradox.  In his wonderful TV series Cosmos, Carl Sagan illustrates this Gedankenexperiment with  the story of two Italian boys (story starts at 21:50, ends 24:55), Paulo and little brother Vincenzo.  The boys and their friends are passing a nice day in a small Italian town.  Paulo decides to break off and spend some time riding through the Italian countryside at near the speed of light, all the more impressive considering he is riding a Vespa.   Einstein’s theory of relativity predicts that Paulo ages more slowly than his brother whom he left behind.  So when Paulo returns, all Paulo’s friends have grown old and died. Only Vincenzo, now a very old man, is left patiently waiting for Paolo in the piazza. Paulo, however, has experienced only a few minutes of time passing and remains a teenager.

A common misconception is that the “paradox” of this story lies in their ages because, the wrong argument goes,  a younger brother can never be older than the first-born brother.  Actually there’s not problem with that.  The real “paradox” raised was to say that since motion is relative, we cannot specify which brother is “really” moving and who was “really” at rest.  Each brother would see the other moving.  So in that case how could one brother age faster than the other since we can reverse the roles and say Paulo is on a stationary Vespa while Vincenzo was on a moving piazza.  The resolution of the paradox is that at some point Paulo had to turn his Vespa around.  Paulo accelerated but not Vincenzo.   The brothers can say who accelerated and the paradox is resolved, i.e. no paradox.   Sagan himself identifies the wrong paradox in this clip.  I am sure Sagan knew better–but we wouldn’t make that mistake on The Big Bang Theory.

After only a few minutes riding at near light-speed on his Vespa, young Paulo finds his little brother Vincenzo is 90 years old. (starts at 21:50 ends 24:55)

Maxwell’s Demon: is a famous Gedankenexperiment posed for the theory of heat.  In a hot gas, molecules are moving faster on average than in a cool gas.   The theory of heat (a.k.a. “thermodynamics”)  says that if you have two bottles of gas at equal temperature and connect them with a pipe, heat will not flow from one to the other.  However each gas has molecules with a variety of speeds around the average.  Imagine a gatekeeper, Maxwell’s Demon, who could preferentially allow fast molecules into one bottle and the slow ones into the other. One gas would heat up while the other cools without the work required by the theory of heat.  The resolution of this paradox is less obvious than Einstein’s twin paradox and physicists still can argue about it.

Wigner’s Friend is a  Gedankenexperiment proposed by the great physicist Eugene Wigner to explore the roles of consciousness in the quantum measurement problem.  It can be discussed as an added layer to the Schroedinger’s cat experiment.  Suppose Wigner leaves the room with the cat of unknown status  in the box while his friend looks in the box.  Typical theorist, he exits the room leaving the dirty work of cleaning up dead cats to an experimentalist friend.  He asks to be told about the experimental results later.   If it is Wigner’s friend’s consciousness that forces the cat to be 100% alive or 100% dead, then even for Wigner, who is out of the room and does not know the result, suddenly lives in a world where the outcome is 100% determined.  Alas, there is no more problem with Wigner living in a world with a superposition of dead/alive cats and corresponding sad/happy friends than there was with the original cat experiment.  I don’t know of anything fruitful that has been gleaned from this Gedankenexperiment.   In fact, I suspect Schroedinger chose a cat in the first place  to have a complex conscious being in the box. Wigner was no slouch, however, so perhaps I am missing something.  One thing is sure.  The next step will be for the theorist to report on the experimentalist’s hard-won findings to the newspapers.

At the same time as the German-speaking scientists of 100 years ago were developing modern physics, their Yiddish-speaking neighbors were writing comedic theater.   Just as physicists worldwide find funny old German words in our technical lexicon, viewers worldwide hear Yiddish words in the situation comedies of today.   Similarities between comedy and physics abound.


18 Responses to “S03E13: The Bozeman Reaction”

  1. astrotsarina Says:

    Great post! And I look forward to watching the TiVo’d episode shortly. Just put the exclamation point at the end (left) of the Yiddish. 😉

    • David Saltzberg Says:

      ! WordPress wouldn’t let me, but since you noticed I tried again and I tricked it.

  2. Simon Says:

    I learned “gedankenexperiment” when my physical chemistry professor tough us about the Carnot cycle. Then, he said Germany had very advanced theoretical physics and chemistry. America even sent student to there learn theoretical physics and theoretical chemistry. Science papers were written in German. :O

  3. Joel Says:

    I’ve got to say, though, I was very surprised noone mentioned Bozeman’s Star Trek connections. Presumably that was at least a factor in its selection (both by Sheldon and the writers)!

  4. shellorz Says:

    I thought the twin paradox was brought by Paul Langevin as an explanation of Einstein’s Relativity. Funnily enough, usually others come up with paradoxes for your theories. Like the EPR paradox wasn’t brought up by Heisenberg or Schrödinger.
    Einstein most famous thought experiment is, IMHO, the train experiment

    • David Saltzberg Says:

      Thanks. I have fixed the text without going into the history.

    • David N. Andrews M. Ed., C. P. S. E. Says:

      “Einstein most famous thought experiment is, IMHO, the train experiment”

      When I had re-sit students of mathematics for GSCE (comprehensive school level leaving certificate in the UK; where I am from), they’d ask me, “what can we do with mathematics?”

      So I’d say “anything!”.

      Much mirth and merriment would ensue as at least one student would invite me to go and urinate in a different room; but, by the end of the lesson, with very little other than a basic knowledge of arithmetic operations and a good look at Pythagoras’ Theorem, they’d get an appreciation for special relativity.

      And the train gedankenexperiment was the very thing I used! Why? Because, if it was good enough for Einstein, it was good enough for me!

  5. Ashish Says:

    Totally unrelated to Physics, I think that this was the first episode in all the three seasons where Sheldon does something illogical apparently. How can he call Howard an acquaintance and penny a friend. No explanation has been given for this unlike when the explanation for ouster of Raj from his friends was given.
    Apart from that a nice episode, though I still miss the physics debates.

  6. arc Says:

    Awesome blog, thanks for that!
    Also nice post here.

    I’ve just found that article about IBM’s graphene transistor breakthrough: http://blogs.zdnet.com/BTL/?p=30447&tag=mncol;txt

    Fascinating how up-to-date the show is.

  7. dirk alan Says:

    i heard shroedinger put kitty litter in the box just in case. cheers.

  8. When you learn a new word, use it three times that day. Today’s word: gedankenexperiment. « I quote myself. Says:

    […] This is where I learned the word gedankenexperiment. If you think the following paragraph is funny and/or interesting, there are lots more on the blog of Saltzberg (as they say in Cern… I learned that from another post). My favorite word in physics is zitterbewegung.  Coming in at close seconds are bremsstrahlung and ansatz.  These technical terms mean “rapid oscillation”,  “braking radiation” and “guess” in German.  (I chose not to even mention eigenvector—because I didn’t want to have to explain it.) However, viewers of tonight’s show saw  Sheldon use the most famous of all German physics words, gedankenexperiment. […]

  9. native german speaker Says:

    “guess” as a translation for “Ansatz” might be a bit missleading. You could as well translate it with “beginning”. Literally, it is more the “point you put the lever”.

  10. Big Bang Forum Says:

    Hi Professor Saltzberg,

    this is the German TBBT fansite (http://www.big-bang-forum.de/), and we just wanted to say again that it is an honor to have you as a part of our forum as an honorary member. 🙂

    To the German words.
    As a German myself and to strain the stereotype that Germans are extremely precise, Sheldon Cooper must love the Germans for that, LOL, I thought I need to point out a few things.

    First of all, the translation of the German word “Ansatz” is not “guess”, these are two different things. The correct German translation of “guess” is “Rateversuch” or “Schätzung” (both mean the same, pretty much a “shot in the dark”).

    “Ansatz” is the beginning (what my previous speaker mentioned) or a bit more precisely “a starting point from where you begin to follow an idea you have that you think could turn out to be promising.”

    Regarding the spelling, in the German writing all nouns start with a capital letter, regardless of the positioning within a sentence.

    Regarding “Zitterbewegung”, the more accurate translation would be “jitter/quiver movement”.
    The correct translation of “rapid oscillation” would be “schnelle Schwingungen.”

    And finally to the “Gedankenexperiment”, the translation “thought experiment” is almost correct.
    The word “thought” is singular, but if you split the German word into two (“Gedanken” and “Experiment”) the word “Gedanken” is the plural form (Gedanke = singular, without the “n” at the end), therefore the precise english translation would be the plural form, “thoughts experiment”. 🙂

    I hope my remarks will be a bit of help for all English natives to get a better understanding of the German language in the field of physics.



  11. Tradução: “S03E13: The Bozeman Reaction (A Reação de Bozeman)” « The Big Blog Theory (em Português!) Says:

    […] feita por Luiz Felipe e revisada por Hitomi a partir de texto extraído de The Big Blog Theory, de autoria de David Saltzberg, originalmente publicado em 18 de Janeiro de […]

  12. Rahul Says:

    I’m not a physicist, but a psychiatrist and I enjoy the show tremendously. In view of this blog, I wish to point out that psychiatry also uses a lot of German words, alluding to its Germanic origins. One of my favourite words is Gedankenlautwerden, which is a type of hallucination.
    Just FYI

  13. feldfrei Says:

    Just for fun (sorry for black humour) – The Quantum Kitty Canon (Schrödinger): http://feldfrei.wordpress.com/2013/01/03/quantenkatzchenkanon/

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