Yoichiro Nambu (南部 陽一郎 Nambu Yōichirō, 18 January 1921 – 5 July 2015) was a Japanese-American physicist and professor at the University of Chicago. Known for his contributions to the field of theoretical physics, he was awarded half of the Nobel Prize in Physics in 2008 for the discovery in 1960 of the mechanism of spontaneous broken symmetry in subatomic physics, related at first to the strong interaction's chiral symmetry and later to the electroweak interaction and Higgs mechanism. The other half was split equally between Makoto Kobayashi and Toshihide Maskawa "for the discovery of the origin of the broken symmetry which predicts the existence of at least three families of quarks in nature."
Nambu in 2005
|Born||18 January 1921|
|Died||5 July 2015 (aged 94)|
|Citizenship||United States (1970–2015)|
|Alma mater||Tokyo Imperial University|
|Known for||Spontaneous symmetry breaking|
|Children||1 Son (John)|
|Awards||Heineman Prize (1970)|
Order of Culture of Japan (1978)
US National Medal of Science (1982)
Dirac Medal (1986)
J.J. Sakurai Prize (1994)
Wolf Prize in Physics (1994/1995)
Pomeranchuk Prize (2007)
Nobel Prize in Physics (2008)
|Institutions||University of Tokyo (1942–49)|
Osaka City University (1949–52)
Institute for Advanced Study (1952–54)
University of Chicago (1954– 2015)
Nambu was born in Tokyo, Japan, in 1921. After graduating from the then Fukui Secondary High School in Fukui City, he enrolled in the Imperial University of Tokyo and studied physics. He received his Bachelor of Science in 1942 and Doctorate of Science in 1952. In 1949 he was appointed to associate professor at the Osaka City University and promoted to professorship the next year at the age of 29.
In 1952, he was invited by the Institute for Advanced Study in Princeton, New Jersey, United States, to study. He moved to the University of Chicago in 1954 and was promoted to professor in 1958. From 1974 to 1977 he was also Chairman of the Department of Physics. He became a United States citizen in 1970.
Nambu proposed the "color charge" of quantum chromodynamics, having done early work on spontaneous symmetry breaking in particle physics, and having discovered that the dual resonance model could be explained as a quantum mechanical theory of strings. He was accounted as one of the founders of string theory.
The Nambu-Goto action in string theory is named after Nambu and Tetsuo Goto. Also, massless bosons arising in field theories with spontaneous symmetry breaking are sometimes referred to as Nambu–Goldstone bosons.
Nambu won numerous honors and awards including the Dannie Heineman Prize (1970), the J. Robert Oppenheimer Memorial Prize (1977), Japan's Order of Culture (1978), the U.S.'s National Medal of Science (1982), the Max Planck Medal (1985), the Dirac Prize (1986), the Sakurai Prize (1994), the Wolf Prize in Physics (1994/1995), and the Franklin Institute's Benjamin Franklin Medal (2005). He was awarded one-half of the 2008 Nobel Prize in Physics "for the discovery of the mechanism of spontaneous broken symmetry in subatomic physics".
The Bethe–Salpeter equation (named after Hans Bethe and Edwin Salpeter) describes the bound states of a two-body (particles) quantum field theoretical system in a relativistically covariant formalism. The equation was actually first published in 1950 at the end of a paper by Yoichiro Nambu, but without derivation.
Due to its generality and its application in many branches of theoretical physics, the Bethe–Salpeter equation appears in many different forms. One form, that is quite often used in high energy physics is
where Γ is the Bethe–Salpeter amplitude, K the interaction and S the propagators of the two participating particles.
In quantum theory, bound states are objects that live for an infinite time (otherwise they are called resonances), thus the constituents interact infinitely many times. By summing up, infinitely many times, all possible interactions that can occur between the two constituents, the Bethe–Salpeter equation is a tool to calculate properties of bound states. Its solution, the Bethe–Salpeter amplitude, is a description of the bound state under consideration.
As it can be derived via identifying bound-states with poles in the S-matrix, it can be connected to the quantum theoretical description of scattering processes and Green's functions.
The Bethe–Salpeter equation is a general quantum field theoretical tool, thus applications for it can be found in any quantum field theory. Some examples are positronium (bound state of an electron–positron pair), excitons (bound state of an electron–hole pair), and mesons (as quark-antiquark bound-state).
Even for simple systems such as the positronium, the equation cannot be solved exactly, although in principle it can be formulated exactly. A classification of the states can be achieved without the need for an exact solution. If one of the particles is significantly more massive than the other, the problem is considerably simplified as one solves the Dirac equation for the lighter particle under the external potential of the heavier particle.Burt Ovrut
Burt Ovrut is an American theoretical physicist best known for his work on heterotic string theory. He is currently Professor of Theoretical High Energy Physics at the University of Pennsylvania.
Ovrut earned his Ph.D. in physics at the University of Chicago in 1978. His doctoral advisors were Benjamin W. Lee and Yoichiro Nambu, and his thesis was on an Sp(4) x U(1) Theory of the Weak and Electromagnetic Interactions.
Ovrut is one of those who pioneered the use of M-theory to explain the Big Bang without the presence of a singularity. Together with Justin Khoury, Paul Steinhardt and Neil Turok, he introduced the notion of
the Ekpyrotic Universe, "... a cosmological model in which the hot big bang universe is produced by the collision of a brane in the bulk space with a bounding orbifold plane, beginning from an otherwise cold, vacuous, static universe".Recently Burt Ovrut and his collaborators constructed a Calabi-Yau compactification that reproduces the Minimal Supersymmetric Standard Model without any exotics.Center for Theoretical Studies, University of Miami
The University of Miami Center for Theoretical Studies was established in 1965 under the direction of Behram Kurşunoğlu, with guidance from J. Robert Oppenheimer and with the support of the University's President Henry King Stanford. The purpose of the Center was to provide a forum for studies in theoretical physics and related fields, to be carried out by short term visitors, postdoctoral researchers, long term members of the Center, and various faculty of the University.
Among others, the long term resident members of the Center included Paul Dirac (1969–1972) and Lars Onsager (1972–1976), while the affiliated faculty included Physics Professors Arnold Perlmutter and Kursunoglu.
Soon after being established, the Center assumed responsibility for the organization of the "Coral Gables Conferences" --- a series of winter scientific meetings on various topics, especially elementary particle physics. These meetings had already begun in January 1964, and continued through December 2003. The original series has now been superseded by the annual Miami physics conferences on elementary particles, astrophysics, and cosmology.From 1969 onwards the Center awarded the J. Robert Oppenheimer Memorial Prize to recognize physics research. Jocelyn Bell Burnell was the 1978 recipient for her discovery of pulsars. Several other recipients of the J. Robert Oppenheimer Memorial Prize were later awarded the Nobel Prize in Physics (specifically, Sheldon Glashow, Yoichiro Nambu, Frederick Reines, Abdus Salam, and Steven Weinberg). The inaugural recipient, Paul Dirac, was already a Nobel laureate.
The Center was located on the University of Miami's campus in Coral Gables, Florida. It closed in 1992 on the retirement of Kursunoglu and was then officially disestablished although the name was retained by the University for possible future use.Chiral symmetry breaking
In particle physics, chiral symmetry breaking is the spontaneous symmetry breaking of a chiral symmetry – usually by a gauge theory such as quantum chromodynamics, the quantum field theory of the strong interaction. Yoichiro Nambu was awarded the 2008 Nobel prize in physics for describing this phenomenon ("for the discovery of the mechanism of spontaneous broken symmetry in subatomic physics").Fukui Prefectural Fujishima High School
Fukui Prefectural Fujishima High School (福井県立藤島高等学校, Fukui Kenritsu Fujishima Kōtō Gakkō) is a high school in Fukui, Japan, founded in 1855. The school is operated by the Fukui Prefectural Board of Education. In 2004 the school was chosen as SSH.
Its best known graduate is probably Yoichiro Nambu, winner of the 2008 Nobel Prize in Physics.Giovanni Jona-Lasinio
Giovanni Jona-Lasinio (born 1932), sometimes called Gianni Jona, is an Italian theoretical physicist, best known for his works on quantum field theory and statistical mechanics. He pioneered research concerning spontaneous symmetry breaking, and the Nambu–Jona-Lasinio model is named after him. When Yoichiro Nambu received the Nobel Prize, Jona-Lasinio gave the Nobel Lecture in his place, as a recognition from Nambu for their joint work . At present, he holds a faculty position in the Physics Department of Sapienza University of Rome, and is a full member of the Accademia dei Lincei.Goldstone boson
In particle and condensed matter physics, Goldstone bosons or Nambu–Goldstone bosons (NGBs) are bosons that appear necessarily in models exhibiting spontaneous breakdown of continuous symmetries. They were discovered by Yoichiro Nambu in the context of the BCS superconductivity mechanism, and subsequently elucidated by Jeffrey Goldstone, and systematically generalized in the context of quantum field theory.These spinless bosons correspond to the spontaneously broken internal symmetry generators, and are characterized by the quantum numbers of these.
They transform nonlinearly (shift) under the action of these generators, and can thus be excited out of the asymmetric vacuum by these generators. Thus, they can be thought of as the excitations of the field in the broken symmetry directions in group space—and are massless if the spontaneously broken symmetry is not also broken explicitly.
If, instead, the symmetry is not exact, i.e. if it is explicitly broken as well as spontaneously broken, then the Nambu–Goldstone bosons are not massless, though they typically remain relatively light; they are then called pseudo-Goldstone bosons or pseudo-Nambu–Goldstone bosons (abbreviated PNGBs).Index of physics articles (Y)
The index of physics articles is split into multiple pages due to its size.
To navigate by individual letter use the table of contents below.J. Robert Oppenheimer Memorial Prize
The J. Robert Oppenheimer Memorial Prize and Medal was awarded by the Center for Theoretical Studies, University of Miami, from 1969. Established in memory of US physicist J. Robert Oppenheimer, the award consisted of a medal, certificate and a $1000 honorarium. It was awarded for "outstanding contributions to the theoretical natural sciences [...] during the preceding decade".The acceptance speech for the inaugural award to Dirac was published as The Development of Quantum Theory (1971).John Henry Schwarz
John Henry Schwarz (; born November 22, 1941) is an American theoretical physicist. Along with Yoichiro Nambu, Holger Bech Nielsen, Joël Scherk, Gabriele Veneziano, Michael Green, and Leonard Susskind, he is regarded as one of the founders of string theory.List of Japanese Nobel laureates
Since 1949, there have been twenty-seven Japanese winners of the Nobel Prize. The Nobel Prize is a Sweden-based international monetary prize. The award was established by the 1895 will and estate of Swedish chemist and inventor Alfred Nobel. It was first awarded in Physics, Chemistry, Physiology or Medicine, Literature, and Peace in 1901. An associated prize, The Sveriges Riksbank Prize in Economic Sciences in Memory of Alfred Nobel, was instituted by Sweden's central bank in 1968 and first awarded in 1969.
The Nobel Prizes in the above specific sciences disciplines and the Prize in Economics, which is commonly identified with them, are widely regarded as the most prestigious award one can receive in those fields. Of Japanese winners, eleven have been physicists, seven chemists, three for literature, five for physiology or medicine and one for efforts towards peace.In the 21st century, in the field of natural science, the number of Japanese winners of the Nobel Prize has been second behind the U.S.Moo-Young Han
Moo-Young Han (November 30, 1934 – May 15, 2016) was a professor of physics at Duke University. Along with Yoichiro Nambu of the University of Chicago, he is credited with introducing the SU(3) symmetry of quarks, today known as the color charge. The color charge is the basis of the strong force as explained by quantum chromodynamics.Nambu mechanics
In mathematics, Nambu dynamics is a generalization of Hamiltonian mechanics involving multiple Hamiltonians. Recall that Hamiltonian mechanics is based upon the flows generated by a smooth Hamiltonian over a symplectic manifold. The flows are symplectomorphisms and hence obey Liouville's theorem. This was soon generalized to flows generated by a Hamiltonian over a Poisson manifold. In 1973, Yoichiro Nambu suggested a generalization involving Nambu-Poisson manifolds with more than one Hamiltonian.Nambu–Goto action
The Nambu–Goto action is the simplest invariant action in bosonic string theory, and is also used in other theories that investigate string-like objects (for example, cosmic strings). It is the starting point of the analysis of zero-thickness (infinitely thin) string behavior, using the principles of Lagrangian mechanics. Just as the action for a free point particle is proportional to its proper time — i.e., the "length" of its world-line — a relativistic string's action is proportional to the area of the sheet which the string traces as it travels through spacetime.
It is named after Japanese physicists Yoichiro Nambu and Tetsuo Goto.Nambu–Jona-Lasinio model
In quantum field theory, the Nambu–Jona-Lasinio model (or more precisely: the Nambu and Jona-Lasinio model) is a complicated effective theory of nucleons and mesons constructed from interacting Dirac fermions with chiral symmetry, paralleling the construction of Cooper pairs from electrons in the BCS theory of superconductivity. The "complicatedness" of the theory has become more natural as it is now seen as a low-energy approximation of the still more basic theory of quantum chromodynamics, which does not work perturbatively at low energies.Pomeranchuk Prize
The Pomeranchuk Prize is an international award for theoretical physics, awarded annually since 1998 by the Institute for Theoretical and Experimental Physics (ITEP) from Moscow. It is named after Russian physicist Isaak Yakovlevich Pomeranchuk, who together with Landau established the Theoretical Physics Department of the Institute.Top quark condensate
In particle physics, the top quark condensate theory (or top condensation) is an alternative to the Standard Model fundamental Higgs field, where the Higgs boson is a composite field, composed of the top quark and its antiquark. These are bound together by a new force called topcolor, analogous to the binding of Cooper pairs in a BCS superconductor, or mesons in the strong interactions. The idea of binding of top quarks is motivated because it is comparatively heavy, with a measured mass is approximately 173 GeV (comparable to the electroweak scale), and so its Yukawa coupling is of order unity, suggesting the possibility of strong coupling dynamics. at higher energy scales.
This model attempts to explain how the electroweak scale may match the
top quark mass.
Top quark condensation is based upon the "infrared fixed point" for the top quark Higgs-Yukawa coupling, proposed in 1981 by Hill,
based upon an earlier proposal of Pendleton and Ross.
The infrared fixed point surprisingly predicted that the top
quark would be heavy, contrary to the prevailing view of the early 1980's. Indeed,
the top quark was discovered in 1995 at the large mass of 173 GeV.
The infrared-fixed point implies that it
is strongly coupled to the Higgs boson at very high energies, corresponding
to the Landau pole of the Higgs-Yukawa coupling. At this high scale the boundstate Higgs forms, and the coupling relaxes in the infrared to its measured value of order unity
by the renormalization group.
The idea in its present form was described by Yoichiro Nambu and subsequently
by Miransky, Tanabashi, and Yamawaki
and Bardeen, Hill and Lindner,
who connected the theory to the renormalization group and improved its predictions.
The simplest top condensation models predicted that the Higgs boson mass would be larger than the observed 173 GeV top quark mass, and have now been ruled out by the LHC discovery of the Higgs boson at a mass scale of 125 GeV.
However, extended versions introducing more particles can be made consistent with the observed top quark mass. The general idea of a composite Higgs boson, connected
in a fundamental way to the top quark, remains compelling, though the full details are
not yet understood.
A composite Higgs boson arises naturally in Topcolor models, that are extensions of the standard model in analogy to quantum chromodynamics. To be natural, without excessive fine-tuning (i.e. to stabilize the Higgs mass from large radiative corrections), the theory requires new physics at a relatively low energy scale. Placing new physics at 10 TeV, for instance, the model predicts the top quark to be significantly heavier than observed (at about 600 GeV vs. 171 GeV). "Top Seesaw" models, also based upon Topcolor, circumvent this difficulty.
Laureates of the Wolf Prize in Physics