Bunji Sakita
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was a Japanese-American theoretical physicist who made important contributions in
quantum field theory In theoretical physics, quantum field theory (QFT) is a theoretical framework that combines classical field theory, special relativity, and quantum mechanics. QFT is used in particle physics to construct physical models of subatomic particles a ...
,
superstring theory Superstring theory is an attempt to explain all of the particles and fundamental forces of nature in one theory by modeling them as vibrations of tiny supersymmetric strings. 'Superstring theory' is a shorthand for supersymmetric string th ...
and discovered
supersymmetry In a supersymmetric theory the equations for force and the equations for matter are identical. In theoretical and mathematical physics, any theory with this property has the principle of supersymmetry (SUSY). Dozens of supersymmetric theories e ...
in 1971. He was a Distinguished Professor of Physics at the
City College of New York The City College of the City University of New York (also known as the City College of New York, or simply City College or CCNY) is a public university within the City University of New York (CUNY) system in New York City. Founded in 1847, Cit ...
.


Early years

Bunji Sakita was born in Japan in 1930 in the
Toyama prefecture is a prefecture of Japan located in the Chūbu region of Honshu. Toyama Prefecture has a population of 1,044,588 (1 June 2019) and has a geographic area of 4,247.61 km2 (1,640.01 sq mi). Toyama Prefecture borders Ishikawa Prefecture to th ...
. He received his bachelor's degree from
Kanazawa University Kanazawa University ( ja, 金沢大学, Kanazawa Daigaku, abbreviated to ja, 金大, Kindai) is a Japanese national university in the city of Kanazawa, the capital of Ishikawa Prefecture. Founded in 1862, it was chartered as a university in 19 ...
in 1953. He then worked with Sakata's group in
Nagoya University , abbreviated to or NU, is a Japanese national research university located in Chikusa-ku, Nagoya. It was the seventh Imperial University in Japan, one of the first five Designated National University and selected as a Top Type university of ...
, obtaining his master's degree in 1956. He was among a select group of Japanese students recruited by
Robert Marshak Robert Eugene Marshak (October 11, 1916 – December 23, 1992) was an American physicist, educator, and eighth president of the City College of New York. Biography Marshak was born in the Bronx, New York City. His parents, Harry and Rose Marshak ...
to come for graduate studies to the
University of Rochester The University of Rochester (U of R, UR, or U of Rochester) is a private university, private research university in Rochester, New York. The university grants Undergraduate education, undergraduate and graduate degrees, including Doctorate, do ...
. In Rochester, Sakita worked with Professor Charles Goebel and received his Ph.D in 1959. He went on to a postdoctoral position and a professorship at the
University of Wisconsin–Madison A university () is an institution of higher (or tertiary) education and research which awards academic degrees in several academic disciplines. ''University'' is derived from the Latin phrase ''universitas magistrorum et scholarium'', which ...
. In his beginning years at Wisconsin, and during a year he spent at the
Argonne National Laboratory Argonne National Laboratory is a science and engineering research national laboratory operated by UChicago Argonne LLC for the United States Department of Energy. The facility is located in Lemont, Illinois, outside of Chicago, and is the lar ...
, he developed the
SU(6) In mathematics, the special unitary group of degree , denoted , is the Lie group of unitary matrices with determinant 1. The more general unitary matrices may have complex determinants with absolute value 1, rather than real 1 in the specia ...
symmetry of the nonrelativistic
quark A quark () is a type of elementary particle and a fundamental constituent of matter. Quarks combine to form composite particles called hadrons, the most stable of which are protons and neutrons, the components of atomic nuclei. All common ...
model generalizing Wigner's supermultiplet symmetry of combining
spin Spin or spinning most often refers to: * Spinning (textiles), the creation of yarn or thread by twisting fibers together, traditionally by hand spinning * Spin, the rotation of an object around a central axis * Spin (propaganda), an intentionally b ...
and
isospin In nuclear physics and particle physics, isospin (''I'') is a quantum number related to the up- and down quark content of the particle. More specifically, isospin symmetry is a subset of the flavour symmetry seen more broadly in the interactions ...
. In 1967, during a visit to Israel, he learned of the
dual resonance model In theoretical physics, a dual resonance model arose during the early investigation (1968–1973) of string theory as an S-matrix theory of the strong interaction. Overview The dual resonance model was based upon the observation that the amplitud ...
, and his later work at
Wisconsin Wisconsin () is a state in the upper Midwestern United States. Wisconsin is the 25th-largest state by total area and the 20th-most populous. It is bordered by Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake M ...
was mostly devoted to this idea. With Goebel, he obtained the many-particle generalization of the
Veneziano amplitude In theoretical physics, the Veneziano amplitude refers to the discovery made in 1968 by Italian theoretical physicist Gabriele Veneziano that the Euler beta function, when interpreted as a scattering amplitude, has many of the features needed to ...
. In work with
Keiji Kikkawa was a Japanese theoretical physicist. Kikkawa received his bachelor's degree from Tokyo Metropolitan University in 1959, and a PhD from the University of Tokyo in 1964. After that he conducted research at the University of Tokyo, the University ...
, M. A. Virasoro and others, he addressed the problem of unitarity of the dual amplitudes, setting up the formalism of dual diagrams, analogous to
Feynman diagram In theoretical physics, a Feynman diagram is a pictorial representation of the mathematical expressions describing the behavior and interaction of subatomic particles. The scheme is named after American physicist Richard Feynman, who introdu ...
s, for the computation of loop amplitudes. In work done with C.S. Hsue, M. A. Virasoro and notably with
Jean-Loup Gervais Jean-Loup Gervais (born 10 September 1936 in Paris) is a French theoretical physicist. Gervais studied physics and mathematics in Paris, where he graduated in 1961 and got his Ph.D. in 1965 as a student of Claude Bouchiat and Philippe Meyer in O ...
, Sakita developed the functional formalism for these calculations in which summation over
Riemann surface In mathematics, particularly in complex analysis, a Riemann surface is a connected one-dimensional complex manifold. These surfaces were first studied by and are named after Bernhard Riemann. Riemann surfaces can be thought of as deformed ve ...
s naturally emerged.


Supersymmetry

In 1971, Jean-Loup Gervais and Bunji Sakita, in a paper titled "Field Theory Interpretation of Supergauges in Dual Models", showed the
boson In particle physics, a boson ( ) is a subatomic particle whose spin quantum number has an integer value (0,1,2 ...). Bosons form one of the two fundamental classes of subatomic particle, the other being fermions, which have odd half-integer s ...
fermion In particle physics, a fermion is a particle that follows Fermi–Dirac statistics. Generally, it has a half-odd-integer spin: spin , spin , etc. In addition, these particles obey the Pauli exclusion principle. Fermions include all quarks and ...
symmetry of the fermionic string theory, writing down the first linear supersymmetric action. In modern parlance the Gervais–Sakita Lagrangian has a local superconformal symmetry. The 1973 work of
Wess Wesley Johnson known by his stage name Wess (August 13, 1945 — September 21, 2009) was an American-born Italian singer and bass guitarist, perhaps mostly known for representing Italy along with Dori Ghezzi in the Eurovision Song Contest 1975 ...
and Zumino extended the two-dimensional
supersymmetry In a supersymmetric theory the equations for force and the equations for matter are identical. In theoretical and mathematical physics, any theory with this property has the principle of supersymmetry (SUSY). Dozens of supersymmetric theories e ...
discovered in string theory to four-dimensional field theories with spacetime supersymmetry. (Different versions of supersymmetry had been discovered by two Soviet physicists, Yu. A. Gol'fand and E.P. Likhtman a little earlier; this was not known to physicists elsewhere at that time.) In 1970, Robert Marshak became president of the City College of New York. Sakita moved there as Distinguished Professor to participate in the rapid expansion of the physics program and to lead the High Energy Group. A strong group was built up with first rate work on many areas such as string theory,
supersymmetry In a supersymmetric theory the equations for force and the equations for matter are identical. In theoretical and mathematical physics, any theory with this property has the principle of supersymmetry (SUSY). Dozens of supersymmetric theories e ...
,
particle In the physical sciences, a particle (or corpuscule in older texts) is a small localized object which can be described by several physical or chemical properties, such as volume, density, or mass. They vary greatly in size or quantity, fro ...
phenomenology and others.


Sakita and CCNY

Sakita was an exceptional mentor with an intense working relationship with many of his students whom he treated as his equals. Many of the CCNY students and research associates of this time have gone onto distinguished careers of their own. In recognition of his many contributions, he was the recipient of a
Guggenheim Fellowship Guggenheim Fellowships are grants that have been awarded annually since by the John Simon Guggenheim Memorial Foundation to those "who have demonstrated exceptional capacity for productive scholarship or exceptional creative ability in the ar ...
in 1970 and was awarded the Nishina Memorial Prize of Japan in 1974.


Death

He died on August 31, 2002 in Japan after a year-long battle with cancer. He is survived by his children Mariko Sakita, Mark Mozeson and Taro Sakita, and his grandchildren Evan, Sarah, and Kayla Mozeson.


References


External links


Bunji Sakita (1930-2002)
* {{DEFAULTSORT:Sakita, Bunji 1930 births 2002 deaths University of Rochester alumni University of Wisconsin–Madison faculty Japanese physicists 20th-century American physicists City College of New York faculty Theoretical physicists Nagoya University alumni Kanazawa University alumni