1/d-expansions for the free energy of weakly embedded site animal models of branched polymers
1/d-expansions for the free energy of weakly embedded site animal models of branched polymers
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支化聚合物弱嵌入位点动物模型自由能的 1/d 展开
DOI:
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发表时间:
2000
期刊:
影响因子:
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通讯作者:
P. J. Peard
中科院分区:
文献类型:
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作者:
D. S. Gaunt;P. J. Peard
We give the 1/d-expansion, to order 1/d5, for the limiting reduced free energy of a weakly embedded two-variable site animal model of branched polymers. Hence, we are able to derive expansions for the free energy of related one-variable models and the growth constant of weakly and strongly embedded trees, again to order 1/d5. We argue that the free energy expansions are asymptotically correct for a small range of fugacities only. Exact results show that animals with a compact hypercubic structure make the overwhelming contribution to the total number of weakly embedded site animals, especially for large d. This result is not reflected in the free energy 1/d-expansions, where trees make the dominant contribution. We also derive new exact enumeration data for lattice animals using intermediate calculations in the derivation of the 1/d-expansions. Thus, we give partition functions for the general d-dimensional hypercubic lattice for one to 13 sites.