Last updated
BornJanuary 14, 1937
New York City, New York
DiedOctober 26, 2015 (aged 78)
NationalityAmerican
Alma mater Harvard University
Known for Renormalization group theory of phase transitions
Application of operator algebras in statistical mechanics
Awards Wolf Prize in Physics (1980)
Elliott Cresson Medal (1986)
Lars Onsager Prize (1998)
Lorentz Medal (2006)
Isaac Newton Medal (2011) [1]
Scientific career
Fields Theoretical physics
Institutions University of Chicago
Doctoral students

Leo Philip Kadanoff (January 14, 1937 – October 26, 2015) was an American physicist. [2] He was a professor of physics (emeritus from 2004) [3] at the University of Chicago and a former President of the American Physical Society (APS). [4] He contributed to the fields of statistical physics, chaos theory, and theoretical condensed matter physics.

A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe. Physicists generally are interested in the root or ultimate causes of phenomena, and usually frame their understanding in mathematical terms. Physicists work across a wide range of research fields, spanning all length scales: from sub-atomic and particle physics, through biological physics, to cosmological length scales encompassing the universe as a whole. The field generally includes two types of physicists: experimental physicists who specialize in the observation of physical phenomena and the analysis of experiments, and theoretical physicists who specialize in mathematical modeling of physical systems to rationalize, explain and predict natural phenomena. Physicists can apply their knowledge towards solving practical problems or to developing new technologies.

The University of Chicago is a private research university in Chicago, Illinois. Founded in 1890 by John D. Rockefeller, the school is located on a 217-acre campus in Chicago's Hyde Park neighborhood, near Lake Michigan. The University of Chicago holds top-ten positions in various national and international rankings.

The American Physical Society (APS) is the world's second largest organization of physicists. The Society publishes more than a dozen scientific journals, including the prestigious Physical Review and Physical Review Letters, and organizes more than twenty science meetings each year. APS is a member society of the American Institute of Physics.

## Biography

Kadanoff was raised in New York City. He received his undergraduate degree and doctorate [5] in physics from Harvard University. After a post-doctorate at the Niels Bohr Institute in Copenhagen, he joined the physics faculty at the University of Illinois in 1965.

The City of New York, usually called either New York City (NYC) or simply New York (NY), is the most populous city in the United States. With an estimated 2017 population of 8,622,698 distributed over a land area of about 302.6 square miles (784 km2), New York is also the most densely populated major city in the United States. Located at the southern tip of the state of New York, the city is the center of the New York metropolitan area, the largest metropolitan area in the world by urban landmass and one of the world's most populous megacities, with an estimated 20,320,876 people in its 2017 Metropolitan Statistical Area and 23,876,155 residents in its Combined Statistical Area. A global power city, New York City has been described as the cultural, financial, and media capital of the world, and exerts a significant impact upon commerce, entertainment, research, technology, education, politics, tourism, art, fashion, and sports. The city's fast pace has inspired the term New York minute. Home to the headquarters of the United Nations, New York is an important center for international diplomacy.

Harvard University is a private Ivy League research university in Cambridge, Massachusetts, with about 6,700 undergraduate students and about 15,250 postgraduate students. Established in 1636 and named for its first benefactor, clergyman John Harvard, Harvard is the United States' oldest institution of higher learning, and its history, influence, and wealth have made it one of the world's most prestigious universities.

The Niels Bohr Institute is a research institute of the University of Copenhagen. The research of the institute spans astronomy, geophysics, nanotechnology, particle physics, quantum mechanics and biophysics.

Kadanoff's early research focused upon superconductivity. In the late 1960s, he studied the organization of matter in phase transitions. Kadanoff demonstrated that sudden changes in material properties (such as the magnetization of a magnet or the boiling of a fluid) could be understood in terms of scaling and universality. With his collaborators, he showed how all the experimental data then available for the changes, called second-order phase transitions, could be understood in terms of these two ideas. These same ideas have now been extended to apply to a broad range of scientific and engineering problems, and have found numerous and important applications in urban planning, computer science, hydrodynamics, biology, applied mathematics and geophysics. In recognition of these achievements, he won the Buckley Prize of the American Physical Society (1977), the Wolf Prize in Physics (1980), the 1989 Boltzmann Medal of the International Union of Pure and Applied Physics, and the 2006 Lorentz Medal.

Superconductivity is a phenomenon of exactly zero electrical resistance and expulsion of magnetic flux fields occurring in certain materials, called superconductors, when cooled below a characteristic critical temperature. It was discovered by Dutch physicist Heike Kamerlingh Onnes on April 8, 1911, in Leiden. Like ferromagnetism and atomic spectral lines, superconductivity is a quantum mechanical phenomenon. It is characterized by the Meissner effect, the complete ejection of magnetic field lines from the interior of the superconductor during its transitions into the superconducting state. The occurrence of the Meissner effect indicates that superconductivity cannot be understood simply as the idealization of perfect conductivity in classical physics.

The term phase transition is most commonly used to describe transitions between solid, liquid, and gaseous states of matter, as well as plasma in rare cases. A phase of a thermodynamic system and the states of matter have uniform physical properties. During a phase transition of a given medium, certain properties of the medium change, often discontinuously, as a result of the change of external conditions, such as temperature, pressure, or others. For example, a liquid may become gas upon heating to the boiling point, resulting in an abrupt change in volume. The measurement of the external conditions at which the transformation occurs is termed the phase transition. Phase transitions commonly occur in nature and are used today in many technologies.

The Wolf Prize in Physics is awarded once a year by the Wolf Foundation in Israel. It is one of the six Wolf Prizes established by the Foundation and awarded since 1978; the others are in Agriculture, Chemistry, Mathematics, Medicine and Arts.

In 1969 he moved to Brown University. He exploited mathematical analogies between solid state physics and urban growth to shed insights into the latter field, so much so that he contributed substantially to the statewide planning program in Rhode Island. In 1978 he moved to the University of Chicago, where he became the John D. and Catherine T. MacArthur Distinguished Service Professor of Physics and Mathematics. Much of his work in the second half of his career involved contributions to chaos theory, in both mechanical and fluid systems. He was elected a Fellow of the American Academy of Arts and Sciences in 1982. [6]

Brown University is a private Ivy League research university in Providence, Rhode Island. Founded in 1764 as the College in the English Colony of Rhode Island and Providence Plantations, it is the seventh-oldest institution of higher education in the United States and one of the nine colonial colleges chartered before the American Revolution.

The American Academy of Arts and Sciences is one of the oldest learned societies in the United States. Founded in 1780, the Academy is dedicated to honoring excellence and leadership, working across disciplines and divides, and advancing the common good.

He was one of the recipients of the 1999 National Medal of Science, awarded by President Clinton. He is a member of the National Academy of Sciences and of the American Philosophical Society as well as being a Fellow of the American Physical Society and of the American Association for the Advancement of Science. During the last decade, he has received the Quantrell Award (for excellence in teaching) from the University of Chicago, the Centennial Medal of Harvard University, the Lars Onsager Prize of the American Physical Society, and the Grande Medaille d'Or of the Académie des sciences de l'Institut de France.

The National Medal of Science is an honor bestowed by the President of the United States to individuals in science and engineering who have made important contributions to the advancement of knowledge in the fields of behavioral and social sciences, biology, chemistry, engineering, mathematics and physics. The twelve member presidential Committee on the National Medal of Science is responsible for selecting award recipients and is administered by the National Science Foundation (NSF).

William Jefferson Clinton is an American politician who served as the 42nd president of the United States from 1993 to 2001. Prior to the presidency, he was the governor of Arkansas from 1979 to 1981, and again from 1983 to 1992, and the attorney general of Arkansas from 1977 to 1979. A member of the Democratic Party, Clinton was ideologically a New Democrat, and many of his policies reflected a centrist "Third Way" political philosophy.

The National Academy of Sciences (NAS) is a United States nonprofit, non-governmental organization. NAS is part of the National Academies of Sciences, Engineering, and Medicine, along with the National Academy of Engineering (NAE) and the National Academy of Medicine (NAM).

His textbook with Gordon Baym, Quantum Statistical Mechanics ( ISBN   020141046X), is a prominent text in the field and has been widely translated.

Gordon Alan Baym is an American theoretical physicist.

The International Standard Book Number (ISBN) is a numeric commercial book identifier which is intended to be unique. Publishers purchase ISBNs from an affiliate of the International ISBN Agency.

With Leo Irakliotis, Kadanoff established the Center for Presentation of Science at the University of Chicago.

In June 2013, it was stated that anonymous donors had provided a \$3.5 million gift to establish the Leo Kadanoff Center for Theoretical Physics at the University of Chicago. [7] He died after complications from an illness on October 26, 2015. [8]

## Publications (selection)

• "Scaling laws for Ising models near ${\displaystyle T_{c}}$", Physics2(263), 1966. (The seminal paper for the development of renormalization group theory; see History of renormalization group theory.)
• "Operator Algebra and the Determination of Critical Indices", Phys. Rev. Lett.23(1430), 1969. (The seminal paper for the development of conformal field theory; see History of conformal field theory.)

## Related Research Articles

In theoretical physics, the renormalization group (RG) refers to a mathematical apparatus that allows systematic investigation of the changes of a physical system as viewed at different scales. In particle physics, it reflects the changes in the underlying force laws as the energy scale at which physical processes occur varies, energy/momentum and resolution distance scales being effectively conjugate under the uncertainty principle.

Kenneth Geddes "Ken" Wilson was an American theoretical physicist and a pioneer in leveraging computers for studying particle physics. He was awarded the 1982 Nobel Prize in Physics for his work on phase transitions—illuminating the subtle essence of phenomena like melting ice and emerging magnetism. It was embodied in his fundamental work on the renormalization group.

Walter Kohn was an Austrian-born American theoretical physicist and theoretical chemist. He was awarded, with John Pople, the Nobel Prize in chemistry in 1998. The award recognized their contributions to the understandings of the electronic properties of materials. In particular, Kohn played the leading role in the development of density functional theory, which made it possible to calculate quantum mechanical electronic structure by equations involving the electronic density. This computational simplification led to more accurate calculations on complex systems as well as many new insights, and it has become an essential tool for materials science, condensed-phase physics, and the chemical physics of atoms and molecules.

Jeffrey Goldstone is a British theoretical physicist and an emeritus physics faculty member at the MIT Center for Theoretical Physics.

Daniel Harry Friedan is an American theoretical physicist and one of three children of the feminist author and activist Betty Friedan.

Emil John Martinec is an American string theorist, a physics professor at the Enrico Fermi Institute at the University of Chicago, and director of the Kadanoff Center for Theoretical Physics. He was part of a group at Princeton University that developed heterotic string theory in 1985.

Michael Ellis Fisher is an English physicist, as well as chemist and mathematician, known for his many seminal contributions to statistical physics, including but not restricted to the theory of phase transitions and critical phenomena.

Bruno Zumino was an Italian theoretical physicist and faculty member at the University of California, Berkeley. He obtained his DSc degree from the University of Rome in 1945.

Carl M. Bender is an American applied mathematician and mathematical physicist. He currently holds the Wilfred R. and Ann Lee Konneker Distinguished Professorship of Physics at Washington University in St. Louis. He also has joint positions as Professor of Physics at the University of Heidelberg and as Visiting Professor of Applied Mathematics and Mathematical Physics at Imperial College, London.

Louise Ann Dolan is an American mathematical physicist and professor of physics at the University of North Carolina at Chapel Hill. She does research in theoretical particle physics, gauge theories, gravity, and string theory, and is generally considered to be one of the foremost experts worldwide in this field. Her work is at the forefront of particle physics today.

Hirosi Ooguri is a theoretical physicist working on quantum field theory, quantum gravity, superstring theory, and their interfaces with mathematics. He is Fred Kavli Professor of Theoretical Physics and Mathematics and the Founding Director of the Walter Burke Institute for Theoretical Physics at California Institute of Technology. He is also the Director of the Kavli Institute for the Physics and Mathematics at the University of Tokyo and the President of the Aspen Center for Physics in Colorado.

Keith Allen Brueckner was an American theoretical physicist who made important contributions in several areas of physics, including many-body theory in condensed matter physics, and laser fusion.

Ramamurti Shankar is the John Randolph Huffman Professor of Physics at Yale University, in New Haven, Connecticut.

John Lawrence CardyFRS is a British theoretical physicist at the University of California, Berkeley. He is best known for his work in theoretical condensed matter physics and statistical mechanics, and in particular for research on critical phenomena and two-dimensional conformal field theory.

Franz Joachim Wegner is emeritus professor for theoretical physics at the University of Heidelberg.

Pier Gerard "Peter" Bouwknegt is Professor of Theoretical Physics and Mathematics at the Australian National University (ANU), and Deputy Director of their Mathematical Sciences Institute. He is an adjunct professor at University of Adelaide.

Ian Keith Affleck is a Canadian physicist specializing in condensed matter physics. He is Killam University Professor, Department of Physics and Astronomy, University of British Columbia.

Alexander Arkadyevich Migdal is a Russian – American physicist and entrepreneur, formerly at Landau Institute for Theoretical Physics, Space Research Institute, Princeton University, ViewPoint Corp, Magic Works LLC, and now at Migdal Research LLC.

G. Peter Lepage is a Canadian theoretical physicist and an academic administrator. He was the Harold Tanner Dean of the College of Arts and Sciences at Cornell University from 2003 to 2013.

## References

1. "Honors by Faculty". uchicago.edu. Archived from the original on 2011-06-13.
2. Brenner, Michael P.; Nagel, Sidney R. (April 2016). "Obituary. Leo Philip Kadanoff". Physics Today: 69. Bibcode:2016PhT....69d..69B. doi:10.1063/pt.3.3146.
3. "Faculty Directory". uchicago.edu. Archived from the original on 2011-06-13.
4. "History of the APS Presidential Line" . Retrieved 23 June 2011.
5. "Theoretical Condensed Matter Physics". uchicago.edu. Archived from the original on 2011-06-18.
6. "Book of Members, 1780–2010: Chapter K" (PDF). American Academy of Arts and Sciences. Retrieved June 21, 2011.
7. "Leo Kadanoff Obituary - Skokie, IL - ChicagoTribune.com". ChicagoTribune.com.