Julian Schwinger Updated +Created
Extremely precocious, borderline child prodigy, he was reading Dirac at 13-14 from the library.
He started working at night and sleeping during the moring/early afternoon while he was at university.
He was the type of guy that was so good that he didn't really have to follow the university rules very much. He would get into trouble for not following some stupid requirement, but he was so good that they would just let him get away with it.
Besides quantum electrodynamics, Julian worked on radar at the Rad Lab during World War II, unlike most other top physicists who went to Los Alamos Laboratory to work on the atomic bomb, and he made important contributions there on calculating the best shape of the parts and so on.
He was known for being very formal mathematically and sometimes hard to understand, in stark contrast to Feynman which was much more lose and understandable, especially after Freeman Dyson translated him to the masses.
However, QED and the men who made it: Dyson, Feynman, Schwinger, and Tomonaga by Silvan Schweber (1994) does emphacise that he was actually also very practical in the sense that he always aimed to obtain definite numbers out of his calculations, and that was not only the case for the Lamb shift.
Richard Feynman Updated +Created
Some of Feynman's key characteristics are:
  • obsession with understanding the experiments well, see also Section "How to teach and learn physics"
  • when doing more mathematical stuff, analogous obsession about starting with a concrete example and then generalizing that into the theory
  • liked to teach others. At Surely You're Joking, Mr. Feynman for example he mentions that one key problem of the Institute for Advanced Study is that they didn't have to teach, and besides that making you feel useless when were not having new ideas, it is also the case that student's questions often inspire you to look again in some direction which sometimes happens to be profitable
    He hated however mentoring others one to one, because almost everyone was too stupid for him
  • interest in other natural sciences, and also random art and culture (and especially if it involves pretty women)
Some non-Physics related ones, mostly highlighted at Genius: Richard Feynman and Modern Physics by James Gleick (1994):
Even Apple thinks so according to their Think different campaign: www.feynman.com/fun/think-different/
Feynman was apparently seriously interested/amused by computer:
Video 1.
Murray Gell-Mann talks about Richard Feynman's intentional anecdote creation
. Source. TODO original interviewer, date and source. Very amusing, he tells how Feynman wouldn't brush his teeth, or purposefully forget to wear jacket and tie when going to the faculty canteen where it was required and so he would use ugly emergency jacket the canteen offered to anyone who had forgotten theirs.
Video 2.
Murray Gell-Mann talks about Feynman's partons by Web of Stories (1997)
Source. Listener is likely this Geoffrey West. Key quote:
Feynman of course, as usual, put it in a form so that the common people could use it, and experimentalists all over the world now thought they understood things because Feynman had put it in such simple language for them.
Two official websites?
In 1948 he published his reworking of classical quantum mechanics in terms of the path integral formulation: journals.aps.org/rmp/abstract/10.1103/RevModPhys.20.367 Space Time Approach to nonrelativistic quantum mechanics (paywalled 2021)