- Robert Kraichnan
Robert Kraichnan (1928-2008) was an American theoretical physicist who made seminal contributions to the theory of
turbulence [ [http://www.nytimes.com/2008/03/08/us/08kraichnan.html?ref=obituaries Robert Kraichnan, Physicist Who Studied Turbulence, Is Dead at 80 - New York Times ] ] .Early work of
Andrey Kolmogorov ,Lars Onsager , andWerner Heisenberg established that it is productive to describe a turbulent fluid with a statistically self-similar velocity field at length scales shorter than the driving force responsible for the flow, but longer than the length scale at which theviscosity allows energy to dissipate. In this regime, energy was assumed to always flow from large length scales to small ones. Among his other achievements in the field, Kraichnan established that in two dimensionalfluid flows theenergy cascade goes in the opposite direction--- from small length scales to large ones. Some of his work centered on perturbative studies of statistical field theories of turbulence, which led to a rapid growth in the field in the 1960's and 1970's.In gravitation theory, Kraichnan was the first to note that General Relativity is the unique self-consistent equation of a spin two particle coupled to a conserved energy-momentum tensor, where the nonlinearities are understood as the graviton responding to its own stress energy [ Kraichnan R. "Special-Relativistic Derivation of Generally Covariant Gravitation Theory" Physical Review 98 1118-1122] . This point of view was later popularized by
Richard Feynman [ R.P. Feynman "The Feynman Lectures on Gravitation"] .He was the recipient of the 1993 Otto Laporte Award. [ [http://www.aps.org/programs/honors/prizes/prizerecipient.cfm?name=Robert%20Kraichnan&year=1993 Prize Recipient ] ] and the 2003 Dirac medal. [ [http://users.ictp.it/~sci_info/awards/Dirac/DiracMedallists/DiracMedal03.html Dirac Medallists 2003 ] ]
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