There is a well-known quote of Feynman on the Bethe ansatz that appeared in an article in Asia-Pacific Physics News,volume 3, 22 (June/July 1988):

"I got really fascinated by these (1 + 1)- dimensional models that are solved by the Bethe ansatz and how mysteriously they jump out at you and work and you don’t know why. I am trying to understand all this better."

I would like to read the article, but interlibrary loan at my institution has been unable to locate it. Does anyone have any further information on the article (for example, the title) or any suggestions on where I might be able to get access to it?

  • $\begingroup$ Where did you find the citation? $\endgroup$
    – d_b
    Commented Sep 4, 2022 at 2:48
  • 1
    $\begingroup$ It is cited in an article by Murray Batchelor (The Bethe Ansatz after 75 years) in the January 2007 issue of Physics Today. It is also quoted in Hans-Peter Eckle's book Models of Quantum Matter: A First Course on Integrability and the Bethe Ansatz as well as some slides from a colloquium Hirosi Ooguri gave at the Aspen Center in 2018. Unfortunately, none of the references give any more information. $\endgroup$
    – oper
    Commented Sep 6, 2022 at 5:31
  • $\begingroup$ (Why is this question community wiki?) $\endgroup$ Commented Dec 19, 2023 at 12:19

1 Answer 1


I emailed Murray Batchelor with this question, and with help of Atsuo Kuniba he has been able to provide me with some more information. The original article is

Feynman, R. P., Difficulties in Applying the Variational Principle to Quantum Field Theories

which is pages 28-40 of

L. Polley and D. E. L. Pottinger (Editors), Proceedings of the International Workshop on Variational Calculations in Quantum Field Theory, Wangerooge, West Germany, 1-4 September 1987, World Scientific (1988) [google books]

Murray wrote to me:

[...] The conference proceedings version seems a little easier to get. [...] This article was reproduced in Asia-Pacific Physics News 3, 22 (June/July 1988), which is where I originally saw it.

The original article is a transcript of a talk by Feynman at that conference, taken by the editors and corrected by Feynman. The first half is the talk itself, the second part is a transcript of the ensuing discussion. The quote appears at the very end of the discussion.


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