Dresden 2017 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 26: Posters - Statistical Physics, Stochastic Thermodynamics

DY 26.11: Poster

Dienstag, 21. März 2017, 18:15–21:00, P3

Percolation transition of Fortuin-Kasteleyn clusters for the three-dimensional ± J random-bond-Ising model — •Hauke Fajen and Alexander K. Hartmann — Institute of Physics, University of Oldenburg

We investigated the behavior of the Wolff algorithm for the ± J Random-Bond-Ising model on a three-dimensional lattice. We studied the percolation transition of the Fortuin-Kasteleyn clusters. Our motivation is that the Wolff algorithm works best when the percolation transition temperature T_p and the phase transition temperatureT_c coincide. Fortuin-Kasteleyn clusters are constructed be randomly drawing subsets of bonds from all satisfied bonds of a given spin configuration. Each satisfied bond is considered with a possibility of 1−e^−2J/T. Therefore we studied the percolation temperature T_p as a function of the fraction p of antiferromagnetic (−J) bonds. To measure the percolation probability we used the Swendsen-Wang algorithm to construct the Fortuin-Kasteleyn clusters. It’s already known that the Wolff algorithm doesn’t work efficiently for p=0.5. Our results show that T_p > T_c for most values of p, only near p=0 T_p is equal T_c. We also studied an effective cluster size near p_c (ferromagnet-spin-glass transition) in the spin-glass phase. Nevertheless, close to T_c the effective cluster sizes remain small, showing that the Wolff algorithm is not efficient for all values p>p_c.