arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2007.09761cond-mat.stat-mechcs.NAmath.NAphysics.comp-ph
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曲面衬底KPZ方程的数值模拟及其普适性

Numerical Simulation and the Universality Class of the KPZ Equation for Curved Substrates

Roya Ebrahimi Viand, Sina Dortaj, Seyyed Ehsan Nedaaee Oskoee, Khadijeh Nedaiasl, Muhammad Sahimi

摘要:

Kardar-Parisi-Zhang(KPZ)表面生长方程已经被分析了三十多年。一些实验表明,界面宽度的幂律$w(t)\sim t^β$保持与在平面表面上生长相同。Escudero(Phys. Rev. Lett. { \bf 100},116101,2008)认为,对于(1+1)维的径向KPZ方程,$w(t)$在长时间极限下应增加为$w(t)\sim [\ln(t)]^{1/2}$. Krug(Phys. Rev. Lett. { \bf 102},139601,2009)认为,然而,界面的动力学必须保持不变的几何形状的变化。其他研究表明,对于径向生长的指数$β$应保持相同的平面的情况下,无论是线性或非线性的增长,但饱和状态将不再达到。我们提出了广泛的数值模拟的结果,在(1+1)维的径向KPZ方程,从一个初始的圆形基板。我们发现,不同于KPZ方程的平面基板,从线性到非线性普适类的过渡是不尖锐的。此外,在长时间极限下,界面宽度随时间呈对数增长,而不是饱和。我们还发现,蒸发占主导地位的增长过程中的非线性项的系数在KPZ方程是小的,并且界面的平均半径随时间的推移而减小,并达到一个最小值,但不是零值。

英文摘要:

The Kardar-Parisi-Zhang (KPZ) equation for surface growth has been analyzed for over three decades. Some experiments indicated the power law for the interface width, $w(t)\sim t^β$, remains the same as in growth on planar surfaces. Escudero (Phys. Rev. Lett. {\bf 100}, 116101, 2008) argued, however, that for the radial KPZ equations in (1+1)-dimension $w(t)$ should increase as $w(t)\sim [\ln(t)]^{1/2}$ in the long-time limit. Krug (Phys. Rev. Lett. {\bf 102}, 139601, 2009) argued, however, that the dynamics of the interface must remain unchanged with a change in the geometry. Other studies indicated that for radial growth the exponent $β$ should remain the same as that of the planar case, regardless of whether the growth is linear or nonlinear, but that the saturation regime will not be reached anymore. We present the results of extensive numerical simulations in (1+1)-dimensions of the radial KPZ equation, starting from an initial circular substrate. We find that unlike the KPZ equation for flat substrates, the transition from linear to nonlinear universality classes is not sharp. Moreover, in the long-time limit the interface width exhibits logarithmic growth with the time, instead of saturation. We also find that evaporation dominates the growth process when the coefficient of the nonlinear term in the KPZ equation is small, and that the average radius of the interface decreases with time and reaches a minimum but not zero value.

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