Quenched Averages for Self-Avoiding Walks and Polygons on Deterministic Fractals

被引:0
作者
Deepak Sumedha
机构
[1] Tata Institute of Fundamental Research,Department of Theoretical Physics
[2] Université,Laboratoire de Physique Théorique et Modéles Statistiques
来源
Journal of Statistical Physics | 2006年 / 125卷
关键词
self-avoiding walks; random media; fractals;
D O I
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学科分类号
摘要
We study rooted self avoiding polygons and self avoiding walks on deterministic fractal lattices of finite ramification index. Different sites on such lattices are not equivalent, and the number of rooted open walks Wn(S), and rooted self-avoiding polygons Pn(S) of n steps depend on the root S. We use exact recursion equations on the fractal to determine the generating functions for Pn(S), and Wn(S) for an arbitrary point S on the lattice. These are used to compute the averages \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\langle P_{n}(S) \rangle$$\end{document},\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\langle W_{n}(S) \rangle$$\end{document},\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\langle \log P_{n}(S) \rangle$$\end{document} and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\langle \log W_{n}(S) \rangle$$\end{document} over different positions of S. We find that the connectivity constant μ, and the radius of gyration exponent \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\nu$$\end{document} are the same for the annealed and quenched averages. However, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\langle \log P_{n}(S) \rangle \simeq n \log \mu + (\alpha_q - 2)\log n$$\end{document}, and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\langle \log W_{n}(S) \rangle \simeq n \log \mu + (\gamma_q-1) log{n}$$\end{document}, where the exponents \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\alpha_q$$\end{document} and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\gamma_q$$\end{document}, take values different from the annealed case. These are expressed as the Lyapunov exponents of random product of finite-dimensional matrices. For the 3-simplex lattice, our numerical estimation gives \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\alpha_q \simeq 0.72837 \pm 0.00001;$$\end{document} and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\gamma_q \simeq 1.37501 \pm 0.00003$$\end{document}, to be compared with the known annealed values \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\alpha_a = 0.73421$$\end{document} and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\gamma_q = 1.37522$$\end{document}.
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页码:55 / 76
页数:21
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共 22 条
  • [1] Barat K.(1995)Statistics of self-avoiding walk on random lattices Phys. Rep. 258 377-11
  • [2] Chakrabarti B. K.(1978)Self-avoiding random walks:some exactly soluble cases J. Math. Phys. 19 5-7810
  • [3] Dhar D.(1984)Diffusion on regular random fractals J. Phys. (Paris) 45 389-undefined
  • [4] Rammal R.(1996)Self-avoiding walks on Sierpinski lattices in two and three dimensions J. Phys. A: Math. Gen. 29 7803-undefined
  • [5] Toulose G.(2002)Log-periodic route to fractal functions Phys. Rev. E 65 021107-undefined
  • [6] Vannimenus J.(1982)Kinetic roughening, stochastic growth, directed polymers and all that Adv. Math. 44 180-undefined
  • [7] Reis F. D. A.(2002)Field theory of self-avoiding walks in random media Phys. Rev. E65 036142-undefined
  • [8] Ordemann A.(1960)Monte Carlo study of self-avoiding walks on a critical percolation cluster Ann. Math. Stat. 31 457-undefined
  • [9] Porto M.(1995)undefined Phys. Rep. 254 215-undefined
  • [10] Roman H. E.(1999)undefined J. Phys. A 32 7843-undefined