Hagen Kleinert

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Hagen Kleinert, 2006

Hagen Michael Kleinert (born June 15, 1941 in Festenberg ) is a German physicist and professor of theoretical physics at the Free University of Berlin .

Life

After graduating from the Humboldt School in Hanover , Kleinert studied physics at the Technical University of Hanover from 1960 to 1963 , then at several universities, a. a. at the Georgia Institute of Technology , in the USA . In 1967 he received his doctorate from the University of Colorado at Boulder , where he a. a. studied with George Gamow , one of the fathers of the Big Bang theory . Since 1969 he has been a professor at the Free University of Berlin.

In collaboration with Richard Feynman , he developed an approximation method for calculating path integrals . This has been expanded to a mathematical method with the help of which divergent power series can be converted into convergent power series . This method is the basis of the currently (2008) most accurate theory of the critical exponents that can be observed in the vicinity of second-order phase transitions . In particular, for superfluid helium , this theory accurately predicted the results measured in a satellite experiment.

With the help of the quark field theory, he found in 1973 the explanation of the algebra of Regge couplings assumed by Nicola Cabibbo , L. Horwitz and Yuval Ne'eman .

His theory of collective quantum fields and the hadronization of quark theories served as templates for numerous developments in the theory of condensed matter , nuclear and elementary particle physics .

At a summer school in Erice in 1978 he suggested the existence of supersymmetry in atomic nuclei, which has since been found experimentally.

Together with H. Duru, he solved the path integral of the hydrogen atom for the first time in 1979 .

In 1981, together with K. Maki, he clarified the structure of the ikosahedral phase of quasicrystals . For superconductors , he predicted a tricritical point in the phase diagram between Type I and Type II in 1982 , which was confirmed by Monte Carlo simulations . The prediction is based on a new disorder field theory that he developed in the two books on Gauge Fields in Condensed Matter . Fluctuating vortex or defect lines are described as elementary excitations with the help of fields. This is a dual version of the Landausch order field theories for phase transitions.

In 1986 he introduced bending stiffness into string theory , in which normally only stresses play a role. This significantly improved the physical properties of the strings. Since the Russian physicist Alexander Polyakov proposed a similar theory at about the same time, the result is also called the Polyakov-Kleinert string.

From the coordinate invariance of path integrals he derived an extension of the theory of distributions in which not only (as in the mathematical theory of distributions ) linear combinations, but also products of distributions are clearly defined. The coordinate invariance is a necessary property of the path integrals so that they are equivalent to the Schrödinger picture of quantum mechanics.

Honors

Books

Web links

Individual evidence

  1. ^ RP Feynman, H. Kleinert: Effective classical partition functions . In: Physical Review . A 34, 1986, pp. 5080-5084. doi : 10.1103 / PhysRevA.34.5080 .
  2. ^ H. Kleinert: Critical exponents from seven-loop strong-coupling φ 4 theory in three dimensions . In: Physical Review . D 60, 1999, pp. 85001-850016. doi : 10.1103 / PhysRevD.60.085001 .
  3. ^ JA Lipa: Specific heat of liquid helium in zero gravity very near the lambda point . In: Physical Review . B 68, 2003, p. 174518. doi : 10.1103 / PhysRevB.68.174518 .
  4. ↑ H. Kleinert: Bilocal Form Factors and Regge Couplings . In: Nuclear Physics . B65, 1973, pp. 77-111. doi : 10.1016 / 0550-3213 (73) 90276-9 .
  5. ↑ N. Cabibbo, L. Horwitz and Y. Ne'eman: The Algebra of Scalar and Vector Vertex Strengths in Regge Residues . In: Physics Letters . 22, number 3, 1966, pp. 336-340.
  6. ^ H. Kleinert: Collective Quantum Fields . In: Advances in Physics . 36, 1978, pp. 565-671.
  7. ^ H. Kleinert: On the Hadronization of Quark Theories, Lectures presented at the Erice Summer Institute 1976 . In: Understanding the Fundamental Constituents of Matter, Plenum Press, New York, 1978, A. Zichichi ed . August, pp. 289-390.
  8. ^ S. Ferrara: Erice Lecture 1978 . In: The New Aspects of Subnuclear Physics, Plenum Press, NY, 1980, A. Zichichi ed . August, p. 40.
  9. ^ A. Metz, J. Jolie, G. Graw, R. Hertenberger, J. Gröger, C. Günther, N. Warr, Y. Eisermann: Evidence for the Existence of Supersymmetry in Atomic Nuclei . In: Physical Review Letters . 83, 1999, p. 1542. doi : 10.1103 / PhysRevLett.83.1542 .
  10. ^ IH Duru, H. Kleinert: Solution of the path integral for the H-atom . In: Physics Letters B . 84, No. 2, 1979, pp. 185-188. doi : 10.1016 / 0370-2693 (79) 90280-6 .
  11. ^ IH Duru and H. Kleinert: Quantum Mechanics of H-Atom from Path Integrals . In: Advances in Physics . 30, No. 2, 1982, pp. 401-435.
  12. ↑ H. Kleinert, K. Maki: Lattice Textures in Cholesteric Liquid Crystals . In: Advances in Physics . 29, 1981, pp. 219-259.
  13. ↑ Publications on this from 1981, 1984 .
  14. ^ H. Kleinert: Disorder Version of the Abelian Higgs Model and the Order of the Superconductive Phase Transition . In: Letters to Il Nuovo Cimento . 35, 1982, pp. 405-412.
  15. ↑ J. Hove, S. Mo, A. Sudbo: Vortex interactions and thermally induced crossover from type-I to type-II superconductivity . In: Physical Review . B 66, 2002, p. 064524. doi : 10.1103 / PhysRevB.66.064524 .
  16. ^ H. Kleinert: The Membrane Properties of Condensing Strings . In: Physics Letters B . 174, 1989, p. 335. doi : 10.1016 / 0370-2693 (86) 91111-1 .
  17. ^ H. Kleinert, A. Chervyakov: Rules for integrals over products of distributions from coordinate independence of path integrals . In: European Physical Journal . C 19, 2001, pp. 743-747. doi : 10.1007 / s100520100600 .
  18. ^ Image: Kleinert with Academic Senate of West University of Timișoara
  19. ^ Image: Honorary doctorate from the Kyrgyz-Russian Slavic University in Bishkek
  20. ↑ Picture: Diploma of Honorary Membership of the Russian International Academy of Creative Endeavors
  21. ^ H. Kleinert: From Landau's Order Parameter to Modern Disorder Fields . In: Lev Davidovich Landau and his Impact on Contemporary Theoretical Physics, publ. in Horizons in World Physics . 264, 2009.
  22. ↑ Web link ( Memento of the original from July 17, 2011 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. to the memory ribbon. @1@ 2Template: Webachiv / IABot / www.novapublishers.com
  23. ↑ EJTP: Majorana Prize ( Memento of 6 January 2009 at the Internet Archive )
personal data
SURNAME Kleinert, Hagen
ALTERNATIVE NAMES Kleinert, Hagen Michael (full name)
BRIEF DESCRIPTION German physicist and university professor
DATE OF BIRTH June 15, 1941
PLACE OF BIRTH Festenberg , Silesia