Toivonen Esko, Molkkari Matti, Räsänen Esa, Laurson Lasse
Computational Physics Laboratory, Tampere University, P.O. Box 692, FI-33014 Tampere, Finland.
Phys Rev Lett. 2022 Oct 21;129(17):175701. doi: 10.1103/PhysRevLett.129.175701.
Roughness of driven elastic interfaces in random media is typically understood to be characterized by a single roughness exponent ζ. We show that at the depinning threshold, due to symmetry breaking caused by the direction of the driving force, elastic interfaces with local, long-range, and mean-field elasticity exhibit asymmetric roughness. It is manifested as a skewed distribution of the local interface heights, and can be quantified by using detrended fluctuation analysis to compute a spectrum of local, segment-level scaling exponents. The asymmetry is observed as approximately linear dependence of the local scaling exponents on the difference of the segment height from the mean interface height.
随机介质中受驱弹性界面的粗糙度通常被认为由单一粗糙度指数ζ表征。我们表明，在脱钉阈值处，由于驱动力方向导致的对称性破缺，具有局部、长程和平均场弹性的弹性界面呈现出不对称粗糙度。它表现为局部界面高度的偏态分布，并且可以通过使用去趋势波动分析来计算局部、段级标度指数的谱进行量化。观察到不对称性表现为局部标度指数与段高度与平均界面高度之差的近似线性依赖关系。
