Mikroskopische Zugänge zur nichtlinearen Mechanik defektreicher Kristalle


In the project, the effects of large deformations on the internal elastic and plastic stress fields in novel disordered crystals shall be studied, both numerically. The position is part of a joint research initiative together wirh groups at the University of Tübingen, Prof. Dr. Martin Oettel and at the Technical University of Vienna, Prof. Dr. Gerhard Kahl which is supported by the German and Austrian Science Foundations.

  • WG Fuchs (Theoretische Physik mit SP Weiche kondensierte Materie)
    Miserez, Florian; Ganguly, Saswati; Haussmann, Rudolf; Fuchs, Matthias (2022): Continuum mechanics of nonideal crystals : Microscopic approach based on projection-operator formalism Physical Review E. American Physical Society (APS). 2022, 106(5), 054125. ISSN 2470-0045. eISSN 2470-0053. Available under: doi: 10.1103/PhysRevE.106.054125

Continuum mechanics of nonideal crystals : Microscopic approach based on projection-operator formalism


We present a microscopic derivation of the laws of continuum mechanics of nonideal ordered solids including dissipation, defect diffusion, and heat transport. The starting point is the classical many-body Hamiltonian. The approach relies on the Zwanzig-Mori projection operator formalism to connect microscopic fluctuations to thermodynamic derivatives and transport coefficients. Conservation laws and spontaneous symmetry breaking, implemented via Bogoliubov’s inequality, determine the selection of the slow variables. Density fluctuations in reciprocal space encode the displacement field and the defect concentration. Isothermal and adiabatic elastic constants are obtained from equilibrium correlations, while transport coefficients are given as Green-Kubo formulas, providing the basis for their measurement in atomistic simulations or colloidal experiments. The approach to the linearized continuum mechanics and results are compared to others from the literature.

Origin (projects)

Funding sources
Name Finanzierungstyp Kategorie Project no.
Sachbeihilfe/Normalverfahren third-party funds research funding program 687/18
Further information
Period: since 28.02.2022