I never wrote a joint paper with my thesis advisor, who was not a big proponent of putting his own name on papers. So the shortest academic path to my academic grandfather is via a colleague, Larry Trueman, at Brookhaven, where I was a post-doc, and our boss, Gian-Carlo Wick. This path is of 'Milgram average length' but contains 3 Nobel Laureates (including, of course, Fermi, who won the Prize the year I was born, for which I can take no credit. :) ). The most salient link is via the great theoretical physicist Eugene P. (for "Paul") Wigner, with whom I studied Quantum Mechanics.
Among his unrecorded quotations is this beautiful remark after having assigned the newly translated text book by Lev Landau for a first year course in Quantum Mechanics. "If you already know Quantum Mechanics, you can see [from this chapter] that Landau knows Quantum Mechanics very well."