Steven C. Frautschi (; born December 6, 1933) is an American

theoretical physicist Theoretical physics is a branch of physics that employs mathematical models and abstractions of physical objects and systems to rationalize, explain, and predict natural phenomena. This is in contrast to experimental physics, which uses experi ...

, currently professor of physics emeritus at the

California Institute of Technology The California Institute of Technology (branded as Caltech) is a private research university in Pasadena, California, United States. The university is responsible for many modern scientific advancements and is among a small group of institutes ...

(Caltech). He is known principally for his contributions to the bootstrap theory of the strong interactions and for his contribution to the resolution of the infrared divergence problem in

quantum electrodynamics In particle physics, quantum electrodynamics (QED) is the Theory of relativity, relativistic quantum field theory of electrodynamics. In essence, it describes how light and matter interact and is the first theory where full agreement between quant ...

(QED). He was named a Fellow of the

American Physical Society The American Physical Society (APS) is a not-for-profit membership organization of professionals in physics and related disciplines, comprising nearly fifty divisions, sections, and other units. Its mission is the advancement and diffusion of ...

in 2015 for "contributions to the introduction of Regge poles into particle physics, elucidation of the role of infrared photons in high energy scattering, and for seminal contributions to undergraduate physics education".

Education and employment

Frautschi graduated from

Harvard College Harvard College is the undergraduate education, undergraduate college of Harvard University, a Private university, private Ivy League research university in Cambridge, Massachusetts, United States. Part of the Harvard Faculty of Arts and Scienc ...

in 1954 and received his PhD from

Stanford University Leland Stanford Junior University, commonly referred to as Stanford University, is a Private university, private research university in Stanford, California, United States. It was founded in 1885 by railroad magnate Leland Stanford (the eighth ...

in 1958, having written his dissertation on '' PC conservation in strong interactions and wide angle pair production and quantum electrodynamics at small distances'', under the supervision of Sidney Drell. Frautschi worked as a postdoctoral researcher in the groups of

Hideki Yukawa Hideki Yukawa (; ; 23 January 1907 – 8 September 1981) was a Japanese theoretical physicist who received the Nobel Prize in Physics in 1949 "for his prediction of the existence of mesons on the basis of theoretical work on nuclear forces". B ...

Kyoto University , or , is a National university, national research university in Kyoto, Japan. Founded in 1897, it is one of the former Imperial Universities and the second oldest university in Japan. The university has ten undergraduate faculties, eighteen gra ...

and later of Geoffrey Chew at the

University of California, Berkeley The University of California, Berkeley (UC Berkeley, Berkeley, Cal, or California), is a Public university, public Land-grant university, land-grant research university in Berkeley, California, United States. Founded in 1868 and named after t ...

. He was an assistant professor at

Cornell University Cornell University is a Private university, private Ivy League research university based in Ithaca, New York, United States. The university was co-founded by American philanthropist Ezra Cornell and historian and educator Andrew Dickson W ...

before moving to Caltech in 1962. At Caltech he was the Executive Officer for Physics in 1988-97, and Master of Student Houses in 1997-2002. He received the Feynman Prize for Excellence in Teaching in 2014.

Work

Subjects of his works

In 1961, Chew and Frautschi discovered that the

meson In particle physics, a meson () is a type of hadronic subatomic particle composed of an equal number of quarks and antiquarks, usually one of each, bound together by the strong interaction. Because mesons are composed of quark subparticles, the ...

s fall into straight-line Regge trajectories (in their scheme, spin is plotted against mass squared on a so-called Chew–Frautschi plot), and the two of them introduced the pomeron into the western literature. Frautschi's most well known contribution to strong-interaction theory was the statistical bootstrap, a prediction that the number of hadronic states grows exponentially with energy. This is nowadays understood as a manifestation of the deconfinement phase transition. The exponential growth is incorporated into

string theory In physics, string theory is a theoretical framework in which the point-like particles of particle physics are replaced by one-dimensional objects called strings. String theory describes how these strings propagate through space and intera ...

, where it is known as the

Hagedorn temperature The Hagedorn temperature, ''T''H, is the temperature in theoretical physics where hadronic matter (i.e. ordinary matter) is no longer stable, and must either "evaporate" or convert into quark matter; as such, it can be thought of as the "boiling p ...

. (This S-matrix approach to the strong interactions was largely abandoned by the particle physics community in the 1970s in light of

quantum chromodynamics In theoretical physics, quantum chromodynamics (QCD) is the study of the strong interaction between quarks mediated by gluons. Quarks are fundamental particles that make up composite hadrons such as the proton, neutron and pion. QCD is a type of ...

.) In 1961, with Donald R. Yennie and Hiroshi Suura, he elucidated the role of infrared photons properly summed in high-energy QED. This work was one of the keys to solving the problem of infrared divergences in

gauge theories In physics, a gauge theory is a type of field theory in which the Lagrangian, and hence the dynamics of the system itself, does not change under local transformations according to certain smooth families of operations (Lie groups). Formally, t ...

. One of Frautschi's doctoral students at Caltech was Roger Dashen.

Publications

* 1982 Entropy in an Expanding Universe. ''Science'' 13/08/1982: Vol. 217, Issue 4560, pp. 593–599 ( DOI: 10.1126/science.217.4560.593)Science Mag
/ref> * 1986 ''The Mechanical Universe, Mechanics and Heat'', Advanced Edition, textbook (Steven C. Frautschi, Richard P. Olenick, Tom M. Apostol, David L. Goodstein). New York: Cambridge University Press (1st pbk. ed. 2008).

Family

His daughters, Jennifer and Laura, are both professional violinists.

References

{{DEFAULTSORT:Frautschi, Steven 1933 births Living people 21st-century American physicists California Institute of Technology faculty American theoretical physicists Harvard College alumni Stanford University alumni Fellows of the American Physical Society