Memories from Caltech

In the mid-1970s, particle physics was hot. Quarks were in. Group theory was in. Field theory was in. And so much progress was being made that it seemed like the fundamental theory of physics might be close at hand. Right in the middle of all this was Murray Gell-Mann – responsible for not one, but most, of the leaps of intuition that had brought particle physics to where it was. There’d been other theories, but Murray’s, with their somewhat elaborate and abstract mathematics, were always the ones that seemed to carry the day.

It was the spring of 1978 and I was 18 years old. I’d been publishing papers on particle physics for a few years. I was in England, but planned to soon go to graduate school in the US, and was choosing between Caltech and Princeton. One weekend afternoon, the phone rang. “This is Murray Gell-Mann”, the caller said, then launched into a monologue about why Caltech was the centre of the universe for particle physics at the time. Perhaps not as star-struck as I should have been, I asked a few practical questions, which Murray dismissed. The call ended with something like, “Well, we’d like to have you at Caltech”.

I remember the evening I arrived, wandering around the empty fourth floor of Lauritsen Lab – the centre of Caltech theoretical particle physics. There were all sorts of names I recognised on office doors, and there were two offices that were obviously the largest: “M. Gell-Mann” and “R. Feynman”. In between them was a small office labelled “H. Tuck”, which by the next day I’d realised was occupied by the older but very lively departmental assistant.

I never worked directly with Murray but I interacted with him frequently while I was at Caltech. He was a strange mixture of gracious and gregarious, together with austere and combative. He had an expressive face, which would wrinkle up if he didn’t approve of what was being said. Murray always grouped people and things he approved of, and those he didn’t – to which he would often give disparaging nicknames. (He would always refer to solid- state physics as “squalid-state physics”.) Sometimes he would pretend that things he did not like simply did not exist. I remember once talking to him about something in quantum field theory called the beta function. His face showed no recognition of what I was talking about, and I was getting slightly exasperated. Eventually I blurted out, “But, Murray, didn’t you invent this?” “Oh”, he said, suddenly much more charming, “You mean g times the psi function. Why didn’t you just say that? Now I understand.”

I could never quite figure out what it was that made Murray impressed by some people and not others. He would routinely disparage physicists who were destined for great success, and would vigorously promote ones who didn’t seem so promising, and didn’t in fact do well. So when he promoted me, I was on the one hand flattered, but on the other hand concerned about what his endorsement might really mean.

Feynman interactions

The interaction between Murray Gell-Mann and Richard Feynman was an interesting thing to behold. Both came from New York, but Feynman relished his “working class” New York accent while Gell-Mann affected the best pronunciation of words from any language. Both would make surprisingly childish comments about the other. I remember Feynman insisting on telling me the story of the origin of the word “quark”. He said he’d been talking to Murray one Friday about these hypothetical particles, and in their conversation they’d needed a name for them. Feynman told me he said (no doubt in his characteristic accent), “Let’s call them ‘quacks’”. The next Monday, he said, Murray came to him very excited and said he’d found the word “quark” in a novel by James Joyce. In telling this to me, Feynman then went into a long diatribe about how Murray always seemed to think the names for things were so important. “Having a name for something doesn’t tell you a damned thing,” Feynman said. Feynman went on, mocking Murray’s concern for things like what different birds are called. (Murray was an avid bird watcher.) Meanwhile, Feynman had worked on particles that seemed (and turned out to be) related to quarks. Feynman had called them “partons”. Murray insisted on always referring to them as “put-ons”.

He was a strange mixture of gracious and gregarious

Even though in terms of longstanding contributions to particle physics, Murray was the clear winner, he always seemed to feel as if he was in the shadow of Feynman, particularly with Feynman’s showmanship. When Feynman died, Murray wrote a rather snarky obituary, saying of Feynman: “He surrounded himself with a cloud of myth, and he spent a great deal of time and energy generating anecdotes about himself.” I never quite understood why Murray – who could have gone to any university in the world – chose to work at Caltech for 33 years in an office two doors down from Feynman.

Murray cared a lot about what people thought of him, but wasn’t particularly good at reading other people. Yet, alongside the brush-offs and the strangeness, he could be personally very gracious. I remember him inviting me several times to his house. He also did me quite a few favours in my career. I don’t know if I would call Murray a friend, though, for example, after his wife Margaret died, he and I would sometimes have dinner together, at random restaurants around Pasadena. It wasn’t so much that I felt of a different generation from him (which of course I was). It was more that he exuded a certain aloof tension, that made one not feel very sure about what the relationship really was.

Murray Gell-Mann had an amazing run. For 20 years he had made a series of bold conjectures about how nature might work – strangeness, V-A theory, SU(3), quarks, QCD – and in each case he had been correct, while others had been wrong. He had one of the more remarkable records of repeated correct intuition in the whole history of science.

He tried to go on. He talked about “grand unification being in the air”, and (along with many other physicists) discussed the possibility that QCD and the theory of weak interactions might be unified in models based on groups such as SU(5) and SO(10). He considered supersymmetry. But quick validations of these theories didn’t work out, though even now it’s still conceivable that some version of them might be correct.

I have often used Murray as an example of the challenges of managing the arc of a great career. From his twenties to his forties, Murray had the golden touch. His particular way of thinking had success after success, and in many ways he defined physics for a generation. By the time I knew him, the easy successes were over. Perhaps it was Murray; more likely, it was just that the easy pickings from his approach were now gone. He so wanted to succeed as he had before, not just in physics but in other fields and endeavours. But he never found a way to do it – and always bore the burden of his early success.

Though Murray is now gone, the physics he discovered will live on, defining an important chapter in the quest for our understanding of the fundamental structure of our universe. 

• This article draws on a longer tribute published on www.stephenwolfram.com.