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arXiv 0704.2004cond-mat.dis-nn
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二维伊辛自旋玻璃畴壁的分形维数

Fractal dimension of domain walls in two-dimensional Ising spin glasses

O. Melchert, A. K. Hartmann

摘要:

我们研究畴壁在二维伊辛自旋玻璃方面的最小重量路径问题。使用这种方法,可以精确地处理大型系统。我们的重点是对畴壁的分形维数$d_f$,它描述了通过$<\ell >\simL^{d_f}$的平均畴壁长度的增长与%%系统尺寸$L\times L$。%% 20.07.07 OM %%探索L=320的系统,我们针对高斯无序的情况产生了$d_f=1.274(2)$,即与之前的研究相比,准确度要高得多。对于双峰无序的情况下,由于该模型的简并性,存在许多等效畴壁,我们得到一个真正的下限$d_f=1.095(2)$和(下)估计$d_f=1.395(3)$作为上限。此外,我们还研究了畴壁长度的分布。它们随系统大小的缩放也可以仅用指数$d_f$来描述,即分布是单分形的。最后,我们研究了畴壁宽度随系统尺寸(“粗糙度”)的增长,并发现了线性行为。

英文摘要:

We study domain walls in 2d Ising spin glasses in terms of a minimum-weight path problem. Using this approach, large systems can be treated exactly. Our focus is on the fractal dimension $d_f$ of domain walls, which describes via $<\ell >\simL^{d_f}$ the growth of the average domain-wall length with %% systems size $L\times L$. %% 20.07.07 OM %% Exploring systems up to L=320 we yield $d_f=1.274(2)$ for the case of Gaussian disorder, i.e. a much higher accuracy compared to previous studies. For the case of bimodal disorder, where many equivalent domain walls exist due to the degeneracy of this model, we obtain a true lower bound $d_f=1.095(2)$ and a (lower) estimate $d_f=1.395(3)$ as upper bound. Furthermore, we study the distributions of the domain-wall lengths. Their scaling with system size can be described also only by the exponent $d_f$, i.e. the distributions are monofractal. Finally, we investigate the growth of the domain-wall width with system size (``roughness'') and find a linear behavior.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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