Bunji Sakita
Encyclopedia
was a Japan
ese-American
theoretical physicist who made important contributions in quantum field theory
, superstring theory
and discovered supersymmetry
in 1971. He was a Distinguished Professor of Physics at the City College of New York
.
in 1953. He then worked with Sakata's group in Nagoya University
, obtaining his master's degree in 1956. He was among a select group of Japanese students recruited by Robert Marshak
to come for graduate studies to the University of Rochester
. In Rochester, Sakita worked with Professor Charles Goebel and received his Ph.D in 1959. He went onto a postdoctoral position and a professorship at the University of Wisconsin–Madison
. In his beginning years at Wisconsin, and during a year he spent at the Argonne National Laboratory
, he developed the SU(6) symmetry of the nonrelativistic quark
model generalizing Wigner's supermultiplet
symmetry of combining spin
and isospin
.
In 1967, during a visit to Israel
, he learned of the dual resonance model
, and his later work at Wisconsin
was mostly devoted to this idea. With Goebel, he obtained the many-particle generalization of the Veneziano amplitude
. In work with Keiji Kikkawa, 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
s, for the computation of loop amplitudes. In work done with C.S. Hsue, M. A. Virasoro and notably with Jean-Loup Gervais, Sakita developed the functional formalism for these calculations in which summation over Riemann surface
s naturally emerged.
–fermion
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
and Zumino
extended the two-dimensional supersymmetry
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
, particle
phenomenology and others.
In recognition of his many contributions, he was the recipient of a Guggenheim Fellowship in 1970 and was awarded the Nishina Memorial Prize of Japan in 1974.
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
ese-American
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
theoretical physicist who made important contributions in quantum field theory
Quantum field theory
Quantum field theory provides a theoretical framework for constructing quantum mechanical models of systems classically parametrized by an infinite number of dynamical degrees of freedom, that is, fields and many-body systems. It is the natural and quantitative language of particle physics and...
, superstring theory
Superstring theory
Superstring theory is an attempt to explain all of the particles and fundamental forces of nature in one theory by modelling them as vibrations of tiny supersymmetric strings...
and discovered supersymmetry
Supersymmetry
In particle physics, supersymmetry is a symmetry that relates elementary particles of one spin to other particles that differ by half a unit of spin and are known as superpartners...
in 1971. He was a Distinguished Professor of Physics at the City College of New York
City College of New York
The City College of the City University of New York is a senior college of the City University of New York , in New York City. It is also the oldest of the City University's twenty-three institutions of higher learning...
.
Early years
Bunji Sakita was born in Japan in 1930 in the Toyama prefecture. He received his bachelor's degree from Kanazawa UniversityKanazawa University
is a national university of Japan located in the city of Kanazawa, the capital of Ishikawa Prefecture.Kanazawa University is divided into two main campuses: Kakuma and Takaramachi. Student enrollment is about 11,000 including 350 international students....
in 1953. He then worked with Sakata's group in Nagoya University
Nagoya University
Nagoya University is one of the most prestigious universities in Japan. It can be seen in the several rankings such as shown below.-General Rankings:...
, obtaining his master's degree in 1956. He was among a select group of Japanese students recruited by Robert Marshak
Robert Marshak
Robert Eugene Marshak was an American physicist dedicated to learning, research, and education.-History:...
to come for graduate studies to the University of Rochester
University of Rochester
The University of Rochester is a private, nonsectarian, research university in Rochester, New York, United States. The university grants undergraduate and graduate degrees, including doctoral and professional degrees. The university has six schools and various interdisciplinary programs.The...
. In Rochester, Sakita worked with Professor Charles Goebel and received his Ph.D in 1959. He went onto a postdoctoral position and a professorship at the University of Wisconsin–Madison
University of Wisconsin–Madison
The University of Wisconsin–Madison is a public research university located in Madison, Wisconsin, United States. Founded in 1848, UW–Madison is the flagship campus of the University of Wisconsin System. It became a land-grant institution in 1866...
. In his beginning years at Wisconsin, and during a year he spent at the Argonne National Laboratory
Argonne National Laboratory
Argonne National Laboratory is the first science and engineering research national laboratory in the United States, receiving this designation on July 1, 1946. It is the largest national laboratory by size and scope in the Midwest...
, he developed the SU(6) symmetry of the nonrelativistic quark
Quark
A quark is an 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. Due to a phenomenon known as color confinement, quarks are never directly...
model generalizing Wigner's supermultiplet
Supermultiplet
In theoretical physics, a supermultiplet is formally a group representation of a supersymmetry algebra. It consists of a collection of particles, called superpartners, corresponding to operators in a quantum field theory which in superspace are represented by superfields.Superfields were...
symmetry of combining spin
Spin (physics)
In quantum mechanics and particle physics, spin is a fundamental characteristic property of elementary particles, composite particles , and atomic nuclei.It is worth noting that the intrinsic property of subatomic particles called spin and discussed in this article, is related in some small ways,...
and isospin
Isospin
In physics, and specifically, particle physics, isospin is a quantum number related to the strong interaction. This term was derived from isotopic spin, but the term is confusing as two isotopes of a nucleus have different numbers of nucleons; in contrast, rotations of isospin maintain the number...
.
In 1967, during a visit to Israel
Israel
The State of Israel is a parliamentary republic located in the Middle East, along the eastern shore of the Mediterranean Sea...
, he learned of the dual resonance model
Dual resonance model
In theoretical physics, a dual resonance model arose the early investigation of string theory as an S-matrix theory of the strong interaction....
, and his later work at Wisconsin
Wisconsin
Wisconsin is a U.S. state located in the north-central United States and is part of the Midwest. It is bordered by Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake Michigan to the east, Michigan to the northeast, and Lake Superior to the north. Wisconsin's capital is...
was mostly devoted to this idea. With Goebel, he obtained the many-particle generalization of the Veneziano amplitude
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 explain the physical properties of strongly...
. In work with Keiji Kikkawa, M. A. Virasoro
Miguel Angel Virasoro
Miguel Angel Virasoro is an Argentine physicist who did most of his work in Italy. The Virasoro algebra is named after him. Together with Giorgio Parisi and Marc Mezard he discovered the...
and others, he addressed the problem of unitarity of the dual amplitudes, setting up the formalism of dual diagrams, analogous to Feynman diagram
Feynman diagram
Feynman diagrams are a pictorial representation scheme for the mathematical expressions governing the behavior of subatomic particles, first developed by the Nobel Prize-winning American physicist Richard Feynman, and first introduced in 1948...
s, for the computation of loop amplitudes. In work done with C.S. Hsue, M. A. Virasoro and notably with Jean-Loup Gervais, Sakita developed the functional formalism for these calculations in which summation over Riemann surface
Riemann surface
In mathematics, particularly in complex analysis, a Riemann surface, first studied by and named after Bernhard Riemann, is a one-dimensional complex manifold. Riemann surfaces can be thought of as "deformed versions" of the complex plane: locally near every point they look like patches of the...
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 bosonBoson
In particle physics, bosons are subatomic particles that obey Bose–Einstein statistics. Several bosons can occupy the same quantum state. The word boson derives from the name of Satyendra Nath Bose....
–fermion
Fermion
In particle physics, a fermion is any particle which obeys the Fermi–Dirac statistics . Fermions contrast with bosons which obey Bose–Einstein statistics....
symmetry of the fermionic string theory
String theory
String theory is an active research framework in particle physics that attempts to reconcile quantum mechanics and general relativity. It is a contender for a theory of everything , a manner of describing the known fundamental forces and matter in a mathematically complete system...
, writing down the first linear supersymmetric action. In modern parlance the Gervais–Sakita Lagrangian has a local superconformal symmetry. The 1973 work of Wess
Julius Wess
Julius Wess was an Austrian theoretical physicist noted as the co-inventor of the Wess–Zumino model and Wess–Zumino–Witten model in the field of supersymmetry...
and Zumino
Bruno Zumino
Bruno Zumino is an Italian theoretical physicist and emeritus faculty at the University of California, Berkeley. He got his bachelor degree from the University of Rome in 1945...
extended the two-dimensional supersymmetry
Supersymmetry
In particle physics, supersymmetry is a symmetry that relates elementary particles of one spin to other particles that differ by half a unit of spin and are known as superpartners...
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
String theory
String theory is an active research framework in particle physics that attempts to reconcile quantum mechanics and general relativity. It is a contender for a theory of everything , a manner of describing the known fundamental forces and matter in a mathematically complete system...
, supersymmetry
Supersymmetry
In particle physics, supersymmetry is a symmetry that relates elementary particles of one spin to other particles that differ by half a unit of spin and are known as superpartners...
, particle
Subatomic particle
In physics or chemistry, subatomic particles are the smaller particles composing nucleons and atoms. There are two types of subatomic particles: elementary particles, which are not made of other particles, and composite particles...
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 in 1970 and was awarded the Nishina Memorial Prize of Japan in 1974.