A special issue of Physics Reports has appeared entitled “Hidenaga Yamagishi’s World”. Unfortunately it’s only available online if you are paying Elsevier, so I won’t post a link (it’s volume 398, issue 4-6). This issue is a memorial to the Japanese particle theorist Hidenaga Yamagishi, who died tragically a few years ago.
Hide was in my entering class at Princeton and we spent a lot of time discussing physics together during our graduate student years and later. He was Witten’s first student, and Witten contributes a touching piece about Hide to the memorial issue, including the comment about his maturity “I suspect that to other students he must sometimes have seemed more like a professor than a fellow student”. I can vouch for the accuracy of that and recall that Hide was probably the one of my fellow theory students that I learned the most from.
Hide came to Princeton from the University of Tokyo, already with a strong background in quantum field theory and particle physics. He got his Ph.D. quite a bit faster than me, and left for a post-doc at MIT. Towards the end of my time as a post-doc at Stony Brook, he arrived there to take a tenure-track job in the nuclear theory group of Gerry Brown.
After I left Stony Brook and moved into the mathematics community, I didn’t hear much about what Hide was doing, until some point in the early-mid 90s when I heard from a mutual friend that he had gone back to Japan, perhaps had been ill, and didn’t really seem to be his old self. Around this time for a few years I got Christmas cards from him and he sent me a couple letters. The last one was in early 1998 and included a manuscript of recent ideas about the topological susceptibility in QCD, a topic we both had worked on and often discussed.
Hide’s thesis was about the effects of a magnetic monopole background on the quantum field theory of electrons. Witten discusses this a bit, but there is a much more extensive discussion in the introduction of the article by Goldhaber, Rebhan, van Nieuwenhuizen and Wimmer. To see some of what he was thinking about near the end of his life, see his article with Ismail Zahed entitled “Is Quantization of QCD Unique at the Non-Perturbative Level?”. They ask the interesting question of how well-defined the whole notion of the theta-vacuum is, given that BRST quantization only fixes invariance under infinitesimal gauge transformations, not addressing what happens with so-called “large” gauge transformations. The manuscript Hide sent me in 1998 was more along these lines.