Murray Gell-Mann

Murray Gell-Mann was born in Lower Manhattan on September 15, 1929, the son of Arthur and Pauline Gelman, Jewish immigrants from Czernowitz in the dying Austro-Hungarian Empire. The hyphen in the surname was the boy’s own invention. He decided early that “Gelman” was insufficiently precise, and he intended to be precise. His father had given up an academic career in linguistics to teach English to other immigrants in a storefront school, and the household ran on the conviction that the universe was knowable provided you read enough books in enough languages. By the time Murray was three years old he was reading the multiplication tables on the side of the bathroom scale. At seven he won a citywide spelling bee. At fourteen he was valedictorian of the Columbia Grammar and Preparatory School, and Yale College took him in as a member of Jonathan Edwards.

He had wanted to study archaeology or natural history or linguistics, but his father, alarmed at the job prospects, pressed him toward engineering. They compromised on physics, which Murray accepted on the grounds that it was the worst subject he had ever taken in school. The undergraduate years at Yale settled it. He represented Yale on the William Lowell Putnam mathematics team in 1947, taking second place, and graduated in 1948 still wearing glasses he disliked and a brain whose appetite was not yet rationed. Princeton rejected him. Harvard accepted him but offered no money. MIT, which he had barely heard of, took him and assigned him to Victor Weisskopf as a research assistant. He told later interviewers that he had been “miserable” at MIT during his first year and that he had briefly contemplated suicide before deciding that, on reflection, this was unreasonable. He completed his doctorate on coupling strengths in nuclear reactions in 1951, at twenty-one.

Murray Gell-Mann (; September 15, 1929 – May 24, 2019) was an American theoretical physicist who played a preeminent role in the development of the theory of elementary particles. Gell-Mann introduced the concept of quarks as the fundamental building blocks of the strongly interacting particles, and the renormalization group as a foundational element of quantum field theory and statistical mechanics. Murray Gell-Mann received the 1969 Nobel…

The fifties were the years of the strange particles. Cosmic rays were dropping into cloud chambers a zoo of new objects, kaons and lambdas and sigmas and xis, whose lifetimes were absurdly long for objects produced by the strong force. They were made fast and decayed slowly, by something like a factor of ten to the fourteen too slowly. Working at Chicago in 1953, and independently of the Japanese physicists Kazuhiko Nishijima and Tadao Nakano who reached the same conclusion, Gell-Mann assigned each particle a new bookkeeping number he called “strangeness.” Strangeness was conserved by the strong interaction but violated by the weak. That single rule pinned the long lifetimes in place. It also marked the moment he stopped being a brilliant student and became the man other physicists watched.

He moved to Caltech in 1955 and stayed for thirty-eight years. With Richard Feynman down the hall the two of them in 1958, in parallel with the team of Sudarshan and Marshak, wrote down the V minus A theory of the weak interaction, identifying its peculiar handedness in the wake of Chien-Shiung Wu’s parity-violation experiment. By 1961 Gell-Mann was looking at the proliferating zoo of hadrons (now numbering well over a hundred) and asking the question that classifying naturalists always ask: what is the family tree? At Caltech in the fall of 1960, by his own account, a chance lunchtime conversation with the mathematician Richard Block tipped him off that the symmetry group he needed was SU(3), the group of three-by-three unitary matrices of determinant one. He grouped the spin-half baryons into an octet and the spin-three-halves baryons into a decuplet, and announced that nature had organized her particles by representations of SU(3). Yuval Ne’eman in London had arrived at the same scheme independently and at the same time. Gell-Mann, ever the linguist, named the classification the “eightfold way,” after the Eightfold Path of the Buddha. He warned his readers not to take the joke too seriously. They took it seriously anyway.

The decuplet had a gap. Nine of the ten baryons it predicted had been seen; the tenth, which he called the omega-minus, had not. He stood up at a 1962 CERN conference and predicted its mass and its decay modes from the spacing of the rest of the multiplet. Within two years the Brookhaven bubble chamber had photographed an omega-minus doing exactly what he said it would. From that moment SU(3) was no longer a clever guess. It was the law of the strong-interaction zoo.

That left the harder question. If hadrons fall into representations of SU(3), what carries the symmetry? In 1964 Gell-Mann answered: three fundamental particles of fractional electric charge, two-thirds and minus-one-third, whose triplets and triplet-antitriplet combinations would generate every observed hadron. He needed a name. Reading Joyce’s Finnegans Wake he came on the line “Three quarks for Muster Mark!” in the seabirds’ cry at the start of Book II, Episode 4. The word had the sound he wanted, three of them just as Joyce had it, and a faint absurdity that suited a particle nobody had ever seen on its own. George Zweig at CERN reached the same model independently and called his version “aces.” Gell-Mann’s name won. The 1969 Nobel Prize in Physics was awarded to him alone, “for his contributions and discoveries concerning the classification of elementary particles and their interactions.”

In 1958, Gell-Mann, in collaboration with Richard Feynman, in parallel with the independent team of E. C. George Sudarshan and Robert Marshak, discovered the chiral structures of the weak interaction of physics and developed the V-A theory (vector minus axial vector theory). This work followed the experimental discovery of the violation of parity by Chien-Shiung Wu, as suggested theoretically by Chen-Ning Yang and Tsung-Dao Lee. Gell-Mann's work in the 1950s involved recently discovered cosmic…

Whether quarks were real or merely a mathematical mnemonic Gell-Mann himself sometimes left ambiguous in print, but by 1972, working with Harald Fritzsch, Heinrich Leutwyler, and William Bardeen, he had committed. They proposed a non-abelian gauge theory in which quarks carry three new charges, which Gell-Mann named “color.” The gauge bosons of the theory he named “gluons.” The full theory he christened quantum chromodynamics. The naming was characteristic. He had renamed, over the course of two decades, an entire experimental discipline, and the names were good enough to stick. Strangeness, the eightfold way, quark, gluon, color, quantum chromodynamics: every word of the working vocabulary of strong-interaction physics passed at one stage through his mouth.

Around the physics ran the other lives. He was an obsessive birdwatcher who could identify hundreds of species by call. He collected pre-Columbian pottery and could date a sherd within a century. He spoke (or claimed to speak, his colleagues said sometimes) thirteen languages, and he corrected the pronunciation of every one of them in others. He helped found the Santa Fe Institute in 1984 with George Cowan and a small band of senior scientists worried that the traditional university departments could no longer hold the questions they were interested in: complexity, emergence, the behavior of adaptive systems that include economies and immune systems and ecosystems and brains. The Institute became his second home after his retirement from Caltech in 1993. He wrote a popular book, The Quark and the Jaguar, published in 1994, in which he tried to lay out for general readers his view that the universe is governed by simple laws and complex contingencies, and that both halves matter.

He had a reputation, not always kind. Colleagues called him brilliant and impossible in roughly the same breath. He corrected etymologies in seminar with the same satisfaction he corrected physics. The journalist George Johnson, whose 1999 biography Gell-Mann reportedly disliked, called it Strange Beauty, after both the strangeness quantum number and his subject’s distinctive temperament. Cormac McCarthy, the novelist, who befriended Gell-Mann late in life and used him as a model for several characters, said simply that Gell-Mann “knew more things about more things than anyone I’ve ever met.” He died at his home in Santa Fe on May 24, 2019, having lived to see the Higgs boson confirmed and the Standard Model whose first letters he had drawn become the most precisely tested theory in the history of science.

In the quantum story he is the man who classified the second layer down. Bohr and Heisenberg had given physics the atom; Pauli and Dirac had given it the electron with spin; the long parade of nuclear physicists had given it the nucleus. Gell-Mann reached inside the nucleus, found that the proton and the neutron were composite, and named the things they were composed of after a line in Joyce. Everything in the Standard Model below the level of the hadron is built on his vocabulary.