next up previous contents
Next: Results Up: Average over disorder Previous: Distribution of impurities   Contents

Dependence on the number of disorder realizations

Once the relevant physical quantities (energy, superfluid and condensate fraction) have been calculated for a given configuration of disorder, the simulation is repeated for different configurations and finally the average over disorder configurations is taken. As the computation for a given disorder configuration is heavy and it takes a lot of time to complete the runs with different configurations, it is very important to understand the behavior of the statistical error due to the average over realizations. The results for the energy are shown in Fig. 4.2.

Figure 4.2: The average of the energy over disorder as a function of the bumber of different disorder realizations. The error bars show the variance of the averaging.
\includegraphics[width=\textwidth]{Econf.eps}

Fortunately, energy and the other quantities converge very rapidly to the mean value. Due to the self-averaging 5 or 6 disorder configurations are enough for most of the cases.