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Group Kümmel: Fields of Research

Current research on nonequilibrium phenomena in inhomogeneous supercondoctors concentrates on the effects resulting from Cooper pair formation and destruction by Andreev scattering at the interfaces between superconducting (S) and normal (N) or semiconducting [1]-[3] regions ( see films on wavepacket scattering events ). The impacts of these effects on vortex motion in type II superconductors [5] and on the Josephson currents in current- and voltage-biased mesoscopic superconducting heterojunctions are calculated ( see figure ), and microwave absorption by superconducting multilayers is computed [6].

Of special interest is the cooperation of Andreev scattering, Bloch oscillations and Zener tunneling in mesoscopic superconducting junctions with normal reflections from conventional barriers, the resulting structures in the current-voltage characteristics, and the inclusion of exchange-correlation effects when high-temperature superconductors are involved.

Research in energy science is dedicated to thermoeconomic, system-analytical studies on the possibilities of energy conservation and emission mitigation by the optimized combination of renewable-energy technologies with those of the rational use of energy in conjuntion with the conventional combustion of fossil fuels [7], [8].

Furthermore, industrial growth and technological progress in major countries is analyzed with the help of a mathematical model which involves energy as a factor of production [9]-[16]; for recent results see [15] and [16]. During the 243. WE-Heraeus-Seminar novel theories of industrial production and economic growth were discussed.

References:

  1. A. Jacobs, R. Kümmel, Andreev scattering, Zener tunneling and anomalous ac Josephson effect, Phys. Rev. B 71, 184504 (2005)
    ( Postscript-Version, 737 kByte)
  2. A. Jacobs, R. Kümmel, Dynamics of conversion of supercurrents into normal currents, and vice versa, Phys. Rev. B 64, 104515 (2001)
    ( Preprint-Postscript-Version, 86 kByte)
  3. A. Jacobs, R. Kümmel, H. Plehn, Proximity Effect, Andreev Reflections, and Charge Transport in Mesoscopic Superconducting-Semiconducting Heterostructures, Superlattices and Microstructures 25, 669 (1999),
    ( Postscript-Version, 124 kByte)
  4. R. Kümmel, Time-dependent Bogoliubov-de Gennes Equations - Mean-Field and Density-Functional Theory, in: Physics and Applications of Mesoscopic Josephson Junctions, H. Ohta, C. Ishii Eds., pp. 19-37 (The Physical Society of Japan, Tokyo, 1999)
  5. S. Hofmann, R. Kümmel, The Moving Vortex Line: Electronic Structure, Andreev Scattering, and Magnus Force, Phys. Rev. B 57, 7904 (1998)
  6. H. Plehn, R. Kümmel, Optical absorption by quasiparticles in superconducting multilayers, Ann. Physik 5, 559-575 (1996)
  7. Th. Bruckner, H.-M. Groscurth, R. Kümmel, Competition and Synergy between Energy Technologies in Municipal Energy Systems, Energy-The International Journal, 1005-1014 (1997)
  8. D. Lindenberger, T. Bruckner, H.-M. Groscurth, R. Kümmel, Optimization of solar district heating systems: seasoned storage, heat pumps, and cogeneration, ENERGY - The International Journal 25, 591-608 (2000)
  9. R. Kümmel, D. Lindenberger, W. Eichhorn, Energie, Wirtschaftswachstum und technischer Fortschritt, Phys. Blätter 53, 869-875 (1997)
  10. R. Kümmel, D. Lindenberger, W. Eichhorn, The Productive Power of Energy and Economic Evolution, Indian Journal of Applied Economics Vol. 8, pp. 231-262 (2000) (Special Issue Essays in Honor of Paul A Samuelson, Part III, July-September 2000),
    ( Postscript-Version, 124 kByte)
  11. R. Kümmel, D. Lindenberger, Energy, technical progress, and industrial growth, in: Advances in Energy Studies - Energy Flows in Ecology and Economy (Proc. of the International Workshop), S. Ulgiati (ed.), Porto Venere (1998)
    ( Postscript-Version, 60 kByte)
  12. R. Kümmel, Energie und Kreativität, B.G. Teubner Verlagsgesellschaft (Stuttgart, Leipzig), 130 Seiten (1998),
    ( Abstract )
  13. R. Kümmel, Energy, Creativity and Sustainable Growth (2001),
    ( Postscript-Version, 128 kByte)  (www.eolss.com)
  14. C. Hall, D. Lindenberger, R. Kümmel, T. Kroeger, and W. Eichhorn, The Need to Reintegrate the Natural Sciences with Economics, BioScience 51, 663 (2001)
  15. R. Kümmel, J. Henn, and D. Lindenberger, Capital, labor, energy and creativity: modeling innovation diffusion, Structural Change and Economic Dynamics, 13, 415 (2002)
    ( pdf-Version, 215 kByte)
  16. R. Kümmel, J. Henn, and D. Lindenberger, Internet Supplement to the article "Capital, Labor, Energy and Creativity: Modeling Innovation Diffusion" (2002)
    ( pdf-Version, 140 kByte)
  17. D. Lindenberger and R. Kümmel, Energy-Dependent Production Functions and the Optimization Modell "PRISE" of Price-Induced Sectoral Evolution, Int. J. Applied Thermodynamics, 5, 101 (2002)
    ( pdf-Version, 300 kByte)

Tagung 'Fortschritt und Risiko', 01. und 02.02.2002

[Research group Kümmel] [Theoretical Physics I] [Physics Departments] [University of Würzburg]

Last modified: 27.09.2005