We study numerically the effective pair potential between star polymers with equal arm lengths and equal number f of arms. The simulations were done for the soft core Domb-Joyce model on the simple cubic lattice, to minimize corrections to scaling and to allow for an unlimited number of arms. For the sampling, we used the pruned-enriched Rosenbluth method (PERM). We find that the potential is much less soft than claimed in previous papers, in particular for f≫1. While we verify the logarithmic divergence of V(r), with r being the distance between the two cores, predicted by Witten and Pincus, we find for f>20 that the Mayer function is hardly distinguishable from that for a Gaussian potential.
@article{arxiv.cond-mat/0312194,
title = {Effective interactions between star polymers},
author = {Hsiao-Ping Hsu and Peter Grassberger},
journal= {arXiv preprint arXiv:cond-mat/0312194},
year = {2009}
}