Advertisement

Simple Models for Complex Relaxation

  • Paolo Sibani
Part of the NATO ASI Series book series (NSSB, volume 222)

Abstract

The nonexponential relaxation of spin glasses, and other complex physical system can be interpreted within two different paradigms. In the ‘parallel’ approach, one assumes the existence of ‘effectively’ independent entities, i.e. clusters or droplets as for instance in Refs. [1,2]. Each of these is characterized by a relaxation time, which can be temperature and age dependent. The nonexponential relaxation follows then from a superposition of independent relaxation processes. Alternatively, one might think of the system as a highly correlated entity, and of relaxation as a series of steps which are subordinate to each other, which is the hierarchical approach[3]. Experimental evidence in support of one picture rather then the other would require detailed information on microscopic correlations, which is so far not available. Even in numerical simulations, the existence of the basic objects of both approaches, has not been conclusively demonstrated. In this situation most theoretical descriptions are highly parametrized and experimentally hard to check. One may then ask how few assumptions one needs to reproduce the experimental data. In this paper we describe an attempt in this direction, i.e. a description of relaxation of spin glass systems at the level of a master equation.

Keywords

Master Equation Spin Glass Temperature Step Level Index Model Susceptibility 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. [1]
    D.S.Fisher and D.A.Huse, Phys. Rev. B38, 373 and 385, (1988) and Phys. Rev. Lett. 55, 1634 (1986)Google Scholar
  2. [2]
    G.J.M. Koper and H J Hilhorst Journal de Physique 49, 429 (1988)CrossRefGoogle Scholar
  3. [3]
    R.G. Palmer, D.L. Stein, E. Abrahams and P.W. Anderson, Phys. Rev. Lett. 53, 958 (1984)ADSCrossRefGoogle Scholar
  4. [4]
    P. Sibani, Phys. Rev. B35, 8572, (1987)ADSCrossRefGoogle Scholar
  5. [5]
    K.H. Hoffmann and P. Sibani, Phys. Rev. A38, 4261, (1988)MathSciNetADSCrossRefGoogle Scholar
  6. [6]
    P. Sibani and K.H. Hoffmann, submitted to Phys. Rev. Lett.Google Scholar
  7. [7]
    K.H. Hoffmann and P. Sibani in preparation.Google Scholar
  8. [8]
    K.H. Hoffmann, S.Grossmann and F. Wegner, Z. Phys. B60, 401 (1985)MathSciNetGoogle Scholar
  9. [9]
    P. Sibani Phys. Rev. B34, 3555 (1986)CrossRefGoogle Scholar
  10. [10]
    H.A Kramers, Physica (The Hague) 7, 284 (1940)MathSciNetADSMATHCrossRefGoogle Scholar
  11. [11]
    A review can be found in K.H. Fisher, Phys. Status Solidi B 130, 13 (1985)CrossRefGoogle Scholar
  12. [12]
    P. Svedlindh, P. Granberg, P. Nordblad, L. Lundgren and H.S. Chen, Phys. Rev. B35, 268 (1986)Google Scholar
  13. [13]
    P. Nordblad, P. Svedlindh, L. Sandlund and L. Lundgren Phys. Lett. Al20, 475, (1987)Google Scholar

Copyright information

© Springer Science+Business Media New York 1990

Authors and Affiliations

  • Paolo Sibani
    • 1
  1. 1.Fysisk InstitutOdense UniversitetOdense MDenmark

Personalised recommendations