A. Brooks Harris

Arthur Brooks Harris , called Brooks Harris, (born March 25, 1935 in Boston , Massachusetts ) is an American physicist .

Life

Harris studied at Harvard University with a bachelor's degree in 1956, a master's degree in 1959 and a doctorate in solid state physics with Horst Meyer in 1962. In 1961/62 he was at Duke University , where he became an instructor in 1962 , and in 1964/65 Research in Great Britain at the Harwell Nuclear Research Center with John Hubbard . From 1965 he was assistant professor and from 1977 professor at the University of Pennsylvania .

He was visiting professor at the University of British Columbia , the University of Oxford (1973, 1986 and 1994), Tel Aviv University (1987, 1995) and McMaster University and visiting scholar at Sandia National Laboratories and the National Institute of Standards and Technology (NIST).

Harris has been married since 1958 and has three children.

plant

Among other things, he dealt with orientation order in solid molecular hydrogen (partly with Horst Meyer), phase transitions in various disordered systems (partly with Tom Lubensky ), crystal structure and dynamics of fullerenes (with T. Yildirim), spin dynamics of frustrated magnets (with AJ Berlinsky , Amnon Aharony ) and symmetry properties of frustrated magnets with simultaneous ferroelectric properties. In 1973 he developed the Harris criterion in Oxford, which indicates the extent to which the critical exponents of a phase transition are modified by random impurities (e.g. defects, dislocations, impurities). Such imperfections “smear” the phase transition and lead to local variations in the transition temperature. The Harris criterion states that if

${\displaystyle \nu \geq {\frac {2}{d}}}$

the faults do not influence the critical behavior (this is then stable against the fault). Here d is the spatial dimension of the system and the critical exponent of the correlation length . For example, in the classic three-dimensional Heisenberg model and thus the Harris criterion is met, while the three-dimensional Ising model has and therefore does not meet the criterion ( ). ${\displaystyle \nu }$ ${\displaystyle \nu =0{,}698}$ ${\displaystyle \nu =0{,}627}$ ${\displaystyle d=3}$

Awards and honors

In 2007 he received the Lars Onsager Prize for his contributions to the statistical physics of disordered systems, especially for the development of the Harris criterion. From 1967 to 1969 he was a Sloan Fellow and 1972/73 Guggenheim Fellow . In 1989 he became a Fellow of the American Physical Society .

Web links

• Onsager Award for Harris

Individual evidence

1. ↑ Life data according to American Men and Women of Science , Thomson Gale 2004
2. ^ AB Harris: Effect of random defects on the critical behavior of Ising models . In: Journal of Physics C: Solid State Physics . tape 7 , no. 9 , 1974, p. 1671–1692 , doi : 10.1088 / 0022-3719 / 7/9/009 .
3. ^ A. Brooks Harris: A Brief History of the Harris Criterion . In: Bulletin of the American Physical Society . Volume 52, No. 1 . American Physical Society, 2007, bibcode : 2007APS..MAR.D3003H .
4. ↑ Thomas Vojta, Rastko Sknepnek: Critical points and quenched disorder: From Harris criterion to rare regions and smearing . In: physica status solidi (b) . tape 241 , no. 9 , July 2004, p. 2118–2127 , doi : 10.1002 / pssb.200404798 , arxiv : cond-mat / 0405070 .