Regensburg 2002 – scientific programme

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DY: Dynamik und Statistische Physik

DY 15: Kritische Ph
änomene und Phasenumwandlungen I

DY 15.2: Talk

Monday, March 11, 2002, 14:45–15:00, H3

Flat histogram method of Wang-Landau and N-fold way — •Ben Jesko Schulz, Kurt Binder, and Marcus Mueller — Institut fuer Physik, WA331, Johannes Gutenberg Universitaet, D55099 Mainz, Germany

We present a method for estimating the density of states of a classical statistical model. The algorithm successfully combines the Wang-Landau flat histogram method with the N-fold way in order to improve efficiency of the original single spin flip version. We test our implementation of the Wang-Landau method with the 2D Ising model for which we determine the tunneling time and the density of states. Furthermore, we show that our new algorithm performs correctly at right edges of an energy interval over which the density of states is computed. This removes a disadvantage of the original single spin flip Wang-Landau method where results showed systematically higher errors in the density of states at right boundaries. We compare our data with the detailed numerical tests presented in a study by Wang and Swendsen where the original Wang-Landau method was tested against various other methods. Finally, we apply our method to a thin Ising film with antisymmetric surface fields. With the density of states we calculate canonical averages of thermodynamic quantities. We compare our results with simulational data obtained from a conventional Monte Carlo algorithm.