The man who postulated the quark, even naming it (citing "two quarks for Muster mark") by James Joyce:
Murray Gell-Mann (
/ˈmʌri ˈɡɛl ˈmæn/; September 15, 1929 – May 24, 2019)
[5] was an American
physicist who received the 1969
Nobel Prize in physics for his work on the theory of
elementary particles. Until his death, he was the
Robert Andrews Millikan Professor of Theoretical Physics Emeritus at the
California Institute of Technology, a distinguished fellow and co-founder of the
Santa Fe Institute, a professor of physics at the
University of New Mexico, and the Presidential Professor of Physics and Medicine at the
University of Southern California.
[6]
Gell-Mann spent several periods at
CERN, among others as a
John Simon Guggenheim Memorial Foundation fellow in 1972.
[7][8]
In 1958, Gell-Mann and
Richard Feynman, in parallel with the independent team of
George Sudarshan and
Robert Marshak, discovered the
chiral structures of the
weak interaction in physics. This work followed the experimental discovery of the
violation of parity by
Chien-Shiung Wu, as suggested by
Chen Ning Yang and
Tsung-Dao Lee, theoretically.
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 that a
quantum number called
strangeness would be conserved by the strong and the electromagnetic interactions, but not by the weak interactions. Another of Gell-Mann's ideas is the
Gell-Mann–Okubo formula, which was, initially, a formula based on empirical results, but was later explained by his
quark model. Gell-Mann and
Abraham Pais were involved in explaining several puzzling aspects of the physics of these particles.
In 1961, this led him (and
Kazuhiko Nishijima) to introduce a classification scheme for
hadrons, elementary particles that participate in the strong interaction. (This scheme had been independently proposed by
Yuval Ne'eman.) This scheme is now explained by the
quark model. Gell-Mann referred to the scheme as the
Eightfold Way, because of the
octets of particles in the classification. (The term is a reference to the
eightfold way of
Buddhism.)
In 1964, Gell-Mann and, independently,
George Zweig went on to postulate the existence of
quarks, particles of which the
hadrons of this scheme 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",
[13] but Gell-Mann's name caught on. Quarks, antiquarks, and gluons were soon established as the underlying elementary objects in the study of the structure of hadrons. He was awarded a
Nobel Prize in physics in 1969 for his contributions and discoveries concerning the classification of elementary particles and their interactions.
[14]
In 1972 he and
Harald Fritzsch introduced the conserved quantum number "
color charge", and later, together with Heinrich Leutwyler, they coined the term
quantum chromodynamics (QCD) as the
gauge theory of the strong interaction. The
quark model is a part of QCD, and it has been robust enough to accommodate in a natural fashion the discovery of new "
flavors" of quarks, which superseded the eightfold way scheme.
At the time of his death, he was the Robert Andrews Millikan Professor of Theoretical Physics Emeritus at
California Institute of Technology as well as a University Professor in the Physics and Astronomy Department of the
University of New Mexico in
Albuquerque, New Mexico, and the Presidential Professor of Physics and Medicine at the
University of Southern California. He was a member of the editorial board of the
Encyclopædia Britannica. In 1984 Gell-Mann co-founded the
Santa Fe Institute—a non-profit theoretical research institute in
Santa Fe, New Mexico—to study complex systems and disseminate the notion of a separate interdisciplinary study of
complexity theory.
He was a postdoctoral fellow at the
Institute for Advanced Study in 1951, and a visiting research professor at the
University of Illinois at Urbana–Champaign from 1952 to 1953.
[15] He was a visiting associate professor at
Columbia University and an associate professor at the
University of Chicago in 1954–55 before moving to the
California Institute of Technology, where he taught from 1955 until he retired in 1993.
Murray Gell-Mann in Nice, 2012
During the 1990s, Gell-Mann's interest turned to the emerging study of complexity. He played a central role in the founding of the
Santa Fe Institute, where he continued to work as a distinguished professor.
He wrote a popular science book about these matters,
The Quark and the Jaguar: Adventures in the Simple and the Complex (1994). The title of the book is taken from a line of a poem by
Arthur Sze: "The world of the quark has everything to do with a jaguar circling in the night".
[16]
The author
George Johnson has written a
biography of Gell-Mann,
Strange Beauty: Murray Gell-Mann, and the Revolution in 20th-Century Physics (1999), which was shortlisted for the Royal Society Book Prize.
[17] Gell-Mann criticized it as inaccurate. The Nobel Prize–winning physicist
Philip Anderson, in his chapter on Gell-Mann from a 2011 book,
[18] says that Johnson's biography is excellent. Both Anderson and Johnson say that Gell-Mann was a perfectionist and that his semibiography,
The Quark and the Jaguar (1994) is consequently incomplete.
In 2012 he and his companion
Mary McFadden published the book
Mary McFadden: A Lifetime of Design, Collecting, and Adventure.
[19]
Gell-Mann introduced, independently of
George Zweig, the
quark—constituents of all
hadrons—having first identified the SU(3)
flavor symmetry of hadrons. This symmetry is now understood to underlie the light quarks, extending
isospin to include
strangeness, a quantum number which he also discovered.
He developed the V−A theory of the
weak interaction in collaboration with
Richard Feynman. In the 1960s, he introduced
current algebra as a method of systematically exploiting symmetries to extract predictions from quark models, in the absence of reliable dynamical theory. This method led to model-independent
sum rules confirmed by experiment and provided starting points underpinning the development of the
Standard Model (SM), the widely accepted theory of elementary particles.
Gell-Mann, along with Maurice Lévy, developed the
sigma model of
pions, which describes low-energy pion interactions. Modifying the integer-charged quark model of
Moo-Young Han and
Yoichiro Nambu,
Harald Fritzsch and Gell-Mann were the first to write down the modern accepted theory of
quantum chromodynamics, although they did not anticipate
asymptotic freedom. In 1969 he received the Nobel Prize in physics for his contributions and discoveries concerning the classification of elementary particles and their interactions.
[20]
Gell-Mann was responsible, together with
Pierre Ramond and
Richard Slansky, and independently of
Peter Minkowski,
Rabindra Mohapatra,
Goran Senjanovic,
Sheldon Lee Glashow, and Tsutomu Yanagida, for the
seesaw theory of neutrino masses, that produces masses at the large scale in any theory with a right-handed neutrino. He is also known to have played a large role in keeping
string theory alive through the 1970s and early 1980s, supporting that line of research at a time when it was unpopular.
Gell-Mann was a proponent of the
consistent histories approach to understanding quantum mechanics.
https://en.wikipedia.org/wiki/Murray_Gell-Mann