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arXiv 0806.0588cond-mat.stat-mechphysics.comp-ph
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Kardar-Parisi-Zhang方程的数值研究

Numerical study of the Kardar-Parisi-Zhang equation

Vladimir G. Miranda, F. D. A. Aarao Reis

摘要:

本文采用Euler离散格式和用指数递减函数代替${(\nabla h)}^2$来抑制不稳定性,数值积分了1+1和2+1维的Kardar-Parisi-Zhang(KPZ)方程。当应用于1+1维方程时,不稳定性控制方法提供了与精确已知结果一致的标度振幅值,与原始方案产生的偏差相反。在2+1维中,我们跨越了模型参数的范围,其中没有观察到Edwards-Wilkinson或随机生长的瞬态,在盒子大小$8\leq L\leq 128$中。我们得到粗糙度指数$0.37\leq α\leq 0.40$和稳态高度分布的偏度$S= 0.25\pm 0.01$和峰度$Q= 0.15\pm 0.1$。这些估计值是外推到大的$L$极限后得到的,这是必要的,因为有效指数和高度分布的估计值中存在显著的有限尺寸效应。另一方面,稳态粗糙度分布显示出弱的标度修正和拉伸指数尾的证据。这些结果证实了以前的估计,从晶格模型,显示其可靠性的KPZ类的代表。

英文摘要:

We integrate numerically the Kardar-Parisi-Zhang (KPZ) equation in 1+1 and 2+1 dimensions using an Euler discretization scheme and the replacement of ${(\nabla h)}^2$ by exponentially decreasing functions of that quantity to suppress instabilities. When applied to the equation in 1+1 dimensions, the method of instability control provides values of scaling amplitudes consistent with exactly known results, in contrast to the deviations generated by the original scheme. In 2+1 dimensions, we spanned a range of the model parameters where transients with Edwards-Wilkinson or random growth are not bserved, in box sizes $8\leq L\leq 128$. We obtain roughness exponent $0.37\leq α\leq 0.40$ and steady state height distributions with skewness $S= 0.25\pm 0.01$ and kurtosis $Q= 0.15\pm 0.1$. These estimates are obtained after extrapolations to the large $L$ limit, which is necessary due to significant finite-size effects in the estimates of effective exponents and height distributions. On the other hand, the steady state roughness distributions show weak scaling corrections and evidence of stretched exponentials tails. These results confirm previous estimates from lattice models, showing their reliability as representatives of the KPZ class.

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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