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arXiv 2109.01616math.APcs.NAmath.NAmath.PR
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三维随机椭圆介质中基于二阶校正子的最优人工边界条件

Optimal artificial boundary conditions based on second-order correctors for three dimensional random elliptic media

Jianfeng Lu, Felix Otto, Lihan Wang

AI总结:

针对三维随机介质中局部电荷产生的电场计算,提出基于二阶校正子的最优人工边界条件,扩展二维算法至三维,考虑四极子,实现尺度最优。

摘要:

我们关注的是数值算法,用于计算由尺度为$\ell$的电荷分布在无限非均匀介质中产生的电场,在这种情况下,介质仅在电荷支撑周围直径为$L\gg\ell$的盒子内已知。我们提出了一种边界条件,在介质是来自具有有限相关范围(设为1,并假设$\ell \gg 1$)的平稳系综的样本时,该条件以压倒性概率在关于$\ell$和$L$的尺度方面是(接近)最优的。该边界条件由定量随机均匀化理论所启发,该理论允许多极展开[BGO20]。\n 这项工作扩展了[LO21],该文献中的算法在二维情形下是最优的,因此我们需要在偶极子之外还考虑四极子。这反过来依赖于二阶校正子(除一阶校正子外)的随机估计。这些估计针对所考虑的有限相关范围系综提供,基于[GO15]的半群方法的扩展。

英文摘要:

We are interested in numerical algorithms for computing the electrical field generated by a charge distribution localized on scale $\ell$ in an infinite heterogeneous medium, in a situation where the medium is only known in a box of diameter $L\gg\ell$ around the support of the charge. We propose a boundary condition that with overwhelming probability is (near) optimal with respect to scaling in terms of $\ell$ and $L$, in the setting where the medium is a sample from a stationary ensemble with a finite range of dependence (set to be unity and with the assumption that $\ell \gg 1$). The boundary condition is motivated by quantitative stochastic homogenization that allows for a multipole expansion [BGO20]. This work extends [LO21], the algorithm in which is optimal in two dimension, and thus we need to take quadrupoles, next to dipoles, into account. This in turn relies on stochastic estimates of second-order, next to first-order, correctors. These estimates are provided for finite range ensembles under consideration, based on an extension of the semi-group approach of [GO15].

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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