Berlin 2005 – wissenschaftliches Programm
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DY: Dynamik und Statistische Physik
DY 40: Statistical Physics (General) I
DY 40.9: Vortrag
Dienstag, 8. März 2005, 12:15–12:30, TU H3010
Approximations to phase transition dynamics of a diluted system — •Hendrik Hansen-Goos1 and Martin Weigt2 — 1Institut für Theoretische Physik, Universität Göttingen — 2Institute for Scientific Interchange, Torino
The dynamics of systems close to liquid-crystalline or liquid-amorphous phase tansition points is studied within a Bethe lattice gas model. We approach the flow of macroscopic observables by a projective approximation scheme (PAS) based on the use of generalized Gibbs ensembles for selected sets of observables which allows for a treatment of non-equilibrium configurations under the restricting assumption of microscopic equipartition.
PAS is applied to a system in the coexistence regime of liquid and crystalline phases for different sets of observables. Comparison with MC-simulated data shows that even a minimal description yields qualitatively good approximations.
Furthermore, PAS correctly predicts the divergence of stuctural relaxation time at the spin-glass instability for a system with a continuous glass-transition. When going to more detailed observables, PAS can be applied with an additional simplification causing a loss of the criticality.
We can conclude that PAS, which can be connected with ideas of dynamical replica theory [1], offers a normalisation for the general procedure “approximation via rate-equations” as recently introduced for diluted spin-systems [2].
[1] S.N. Laughton, A.C.C. Coolen and D. Sherrington, J. Phys. A 29, 763 (1996); [2] G. Semerjian and M. Weigt, J. Phys. A 37, 5525 (2004).