A second spanning cluster is drawn at on an lattice from a different seed and…

PHYSICS · Multi-part · Fermi University Physics · Computational Physics · Thermal, Statistical & Complex Systems · Monte Carlo and lattice simulation of physical systems

Computational Physics, Ch Rules on a lattice: diffusion, percolation and growth

Problem

A second spanning cluster is drawn at p=0.593p=0.593 on an L=2048L=2048 lattice from a different seed and box-counted about the occupied site nearest its own centroid, exactly as in the text. The counts Ncl(R)N_{\rm cl}(R) inside a box of half-width RR areR248163264128200Ncl(R)1231110543201382862794667228\begin{array}{c|cccccccc} R & 2 & 4 & 8 & 16 & 32 & 64 & 128 & 200\\ N_{\rm cl}(R) & 12 & 31 & 110 & 543 & 2013 & 8286 & 27946 & 67228 \end{array} ((a)) Fit a straight line to log⁡Ncl\log N_{\rm cl} against log⁡R\log R over all eight points and report the slope with the standard error the fit returns. ((b)) The exact value for a percolation cluster at the threshold in two dimensions is 91/4891/48. Say how far the measurement sits from it, in units of its own uncertainty, and whether the two agree. ((c)) Refit using only the four points with R≤16R\le16. Report that slope, say how much range it covers, and say whether the number may be called a fractal dimension.

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