0

Murray Gell-Mann
(born in 1929)

Is an American physicist who received the 1969 Nobel Prize in physics for his work on the theory of elementary particles.

Born on New York's Lower East Side into a family of Jewish immigrants from Czernowitz [1], Gell-Mann quickly revealed himself as a child prodigy. Propelled by an intense boyhood curiosity and love for nature, he entered Yale at fifteen after graduating valedictorian from the Columbia Grammar and Preparatory School. He was awarded a Nobel Prize in physics in 1969 for his discovery of a system for classifying subatomic particles.

Gell-Mann's work in the 1950s involved recently discovered cosmic ray particles that came to be called kaons and hyperons. Classifying these particles led him to propose a new quantum number called strangeness. Another of Gell-Mann's triumphs is the Gell-Mann–Nishijima formula, which was, initially, a formula from empirical results, but was later explained by the quark model. Gell-Mann and Abraham Pais were involved in explaining many puzzling aspects of the physics of these particles.

In 1961, this led him (and Kazuhiko Nishijima) to introduce a classification of elementary particles called hadrons (also independently proposed by Yuval Ne'eman at around the same time). This scheme is now explained by the quark model. Gell-Mann's own name for the classification scheme was the eightfold way, because of the octets of particles in the classification. The term is a reference to the eightfold way of Buddhism — a choice which is reflective of Gell-Mann's eclectic interests.

Gell-Mann, and, independently, George Zweig, went on, in 1964, to postulate the existence of quarks, the particles from which the hadrons are composed. The name was coined by Gell-Mann and is a reference to the novel Finnegans Wake, by James Joyce ("Three quarks for Muster Mark!" - book 2, episode 4). Zweig had referred to the particles as "aces" but Gell-Mann's name caught on.

Quarks were soon accepted as the underlying elementary objects in the study of the structure of hadrons. In 1972 he introduced with Harald Fritzsch the quantum number 'color' and later, in a joint paper with Heinrich Leutwyler, the full theory of quantum chromodynamics (QCD) was released as the gauge theory of strong interactions (cf. references).

The quark model is part of QCD, and has been robust enough to survive the discovery of other flavours of quarks.

Gell-Mann and Richard Feynman, working together, and a rival group of George Sudarshan and Robert Marshak, were the first to discover the vector structure of the weak interaction in physics. This work followed the seminal discovery of parity violation by Chien-Shiung Wu, as suggested by Chen-Ning Yang and T. D. Lee.

In the 1990s his interest turned to the emerging study of complexity, where he was closely associated with the Santa Fe Institute. He wrote a popular science book about these matters, The Quark and the Jaguar: Adventures in the Simple and the Complex. The title of the book is taken from a line of an Arthur Sze poem: "The world of the quark has everything to do with a jaguar circling in the night."

George Johnson wrote a major biography of Gell-Mann, which is entitled Strange Beauty: Murray Gell-Mann and the Revolution in 20th-Century Physics.