Regensburg 2007 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 30: Poster II

DY 30.29: Poster

Donnerstag, 29. März 2007, 16:00–18:00, Poster D

Fractal dimension of domain walls in two-dimensional Ising spin glasses — •Oliver Melchert and Alexander K. Hartmann — Institut für Theoretische Physik, Georg-August-Universität Göttingen

We study the problem of finding domain-wall excitations on 2d Ising spin glasses in terms of a shortest-path problem. Purpose of this ground-state study is to shed light on the fractal dimension d_f of domain walls, where d_f describes the scaling of the mean domain wall length with the system size L, i.e. ⟨ ℓ ⟩ ∝ L^d_f. Exploring systems up to L=300 we yield d_f=1.271(1) for the case of gaussian disorder, in support of previous findings. The case of bimodal disorder exhibits a high degeneracy of ground states and thus allows for numerous domain walls with minimal energy. Here, we are able to give a true lower and an estimate for the upper bound of the fractal dimension: d_f^low = 1.097(1) and d_f^up = 1.396(10).